Guys,
Loads of talk of the reliability or otherwise of the Punsun engine. Seems only fair to share my experiences with others thinking of investing in this engine.
Just got back from the Hamm Rally courtesy of a recovery lorry. One minor problem on the way over when an injection pipe fractured at the olive. No great shakes though and back on the road in an hour or so after some very helpful dutch guys in a truck garage found a similar line from a refrigeration unit that was bent to fit.
Trundling back home though, enjoying the ride and the sun, when I became aware of an unfamiliar noise. Lived with it for a short while as the bike was still running well, before deciding to pull in to check it out.
It was immediatly obvious all was not well by the amount of engine oil over the crankcases behind the rear pot. A quick wipe around revealed a crack in the crank cases roughly in the middle above the engine mounts spreading across the case to the side cover on the crank side, then carrying on the other side of the gasket up to the fuel pump.
Incredibly I managed to limp the last 60km back to the Ferry, certainly spreading the crack further and covering rear tyre and brakes in oil in the process.
One possible theory is the engine mounts offered no flex, and the engine gave way. I was fully prepared for all manor of issues with a budget engine but certainly did not expect a catastrophic failure.
Add this to the crank issues and my advice would be to hold off buying one of these until Chinese manufacturing quality has caught up to modern standards.
Otherwise a great weekend, great crowd of people at a venue perfect for the job and some awesome innovation on display. Many thanks to all those who make it happen.
Extra thanks to Diesel Dave for the advice and banter throughout. Also for towing me off the ferry, through customs and into England. Oh the shame!
Roverthetop, hold off on the 20t sprocket, I aint gonna be needing it for some time.
Cheers, Mark
Punsun Kaput!!!
Moderators: Dan J, Diesel Dave, Crazymanneil, Stuart
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Diesel Dave
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Punsun No Go
Mark, good to hear you got home OK!
I was expecting to see you and the AA wagon overtake on the 12 heading back for the smoke/M25.
From the motorway stop on the return before it all went tits up.
Cheers
Dave
I was expecting to see you and the AA wagon overtake on the 12 heading back for the smoke/M25.
From the motorway stop on the return before it all went tits up.
Cheers
Dave
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roverthetop
- I luv the smell of Diesel...
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mark,
sorry to hear the trouble. VERY disappointing to be sure. anything to be done for mine? rubber mount the engine? is it due to the side load you think? bouncing in a motorcycle? revving up and down?
glad the rally was decent.
b
sorry to hear the trouble. VERY disappointing to be sure. anything to be done for mine? rubber mount the engine? is it due to the side load you think? bouncing in a motorcycle? revving up and down?
glad the rally was decent.
b
dnepr lombardini 854cc convert
kwaker punsun vtwin convert (SVO as well)
harley sporty (cvt and SVO) done
harley softail (SVO) 6 spd in the works
kwaker punsun vtwin convert (SVO as well)
harley sporty (cvt and SVO) done
harley softail (SVO) 6 spd in the works
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ShovelHead Fred
- I don't post much...
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Photos... Got Photos?
Been following your progress on this bike.
Sorry to here about the KaPuting. Do you have photos of how you mounted the engine? And a photo of the crack in the engine may be useful.
_F
Sorry to here about the KaPuting. Do you have photos of how you mounted the engine? And a photo of the crack in the engine may be useful.
_F
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Diesel Dave
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If it makes you feel any better
Mark,
If it makes you feel any better I've just discovered one of my gearbox bearings in Kaput too.
71,630 miles of use, abuse and general mayhem so perhaps this can be forgiven - a couple of times the engne has been hanging off the primary chain, once or twice I've got me feet mixed up and jammed it into gear without the clutch thinking I was hitting the brake.
I'll swap over to the spare brit 4 speeder at the weekend and have the other rebuilt in a jiffy.
Onwards and upwards!
Dave
If it makes you feel any better I've just discovered one of my gearbox bearings in Kaput too.
71,630 miles of use, abuse and general mayhem so perhaps this can be forgiven - a couple of times the engne has been hanging off the primary chain, once or twice I've got me feet mixed up and jammed it into gear without the clutch thinking I was hitting the brake.
I'll swap over to the spare brit 4 speeder at the weekend and have the other rebuilt in a jiffy.
Onwards and upwards!
Dave
Fred,
Its tricky to photograph the engine mounts and cracks in the casing with the engine in the bike.
I need to wait for assistance before dropping the engine. I did my back in whilst man handling a jap four engine some time ago and am not keen to repeat the experience.
There is a photo of the head steady in the Ural thread, I think. I'll take photo's of the other damage asap.
Basically it seems some of these engines shake or rock worse than others. Mine was a shaker. It was pretty universally agreed that I would have been a fool if I did not support the heads in a motorcycle application.
It is possible that the head steady and engine mounts were so good that the engine was the weak point.
It is suspicious that the cracking appears to have originated just below a spine/brace down the back of the barrel, clearly designed to assist with strain here.
Larry,
I spotted the welding too. It was in exactly the same spot my crack finished.
I may have just been really unlucky and had a flaw in the casing but if you have one of these lumps waiting for a project, I would definatly advise going the rubber mount route.
Cheers, Mark
Its tricky to photograph the engine mounts and cracks in the casing with the engine in the bike.
I need to wait for assistance before dropping the engine. I did my back in whilst man handling a jap four engine some time ago and am not keen to repeat the experience.
There is a photo of the head steady in the Ural thread, I think. I'll take photo's of the other damage asap.
Basically it seems some of these engines shake or rock worse than others. Mine was a shaker. It was pretty universally agreed that I would have been a fool if I did not support the heads in a motorcycle application.
It is possible that the head steady and engine mounts were so good that the engine was the weak point.
It is suspicious that the cracking appears to have originated just below a spine/brace down the back of the barrel, clearly designed to assist with strain here.
Larry,
I spotted the welding too. It was in exactly the same spot my crack finished.
I may have just been really unlucky and had a flaw in the casing but if you have one of these lumps waiting for a project, I would definatly advise going the rubber mount route.
Cheers, Mark
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taildraggin
- I luv the smell of Diesel...
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Graham Stitz
- I don't post much...
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- Location: China
Re: Punsun Diesel Kaputt
I'm starting the process of buying a Punsun/Winsun to put in either a Guzzi or Dnepr frame, with the 4sp Dnepr gearbox and either the original bevel drive or a Jap LH-side turned upside down and put on the right.
The quality of the Punsun is naturally of interest. I'd be interested to hear what Roverthetop's experience with Punsun is, and there are seveal others who've used Punsun, too. My impression is that they're somewhat like the Ural motor of the 70s. I've heard of Ural owners who 'blueprinted' their motors before the first start: fully balance the crank and flywheel, clean the swarf out of the crankcase, blow the grease out of the lubrication lines/oil galleries, replace main and big-end bearings, etc. Then do a really gradual run-in and regular oil changes with good oil. Some blokes are still on their original 70s engine, others have blown them up enough times to go the BMW conversion route.
Perhaps Punsuns should be treated like Urals and not Hondas? I'm also thinking of a sump extension and deeper oil pickup, windage plate (if it's not there), high pressure oil pump, etc. Is 3600rpm the sustained top speed, or should users stick to something lower? Synthetic oil? Beef up the crankcase? Throw away the case and transfer all the internals to a BMW or Guzzi (or Ducati??
) case?
I don't like asking silly questions, but I'd rather ask them than buy an expensive boat anchor.
The quality of the Punsun is naturally of interest. I'd be interested to hear what Roverthetop's experience with Punsun is, and there are seveal others who've used Punsun, too. My impression is that they're somewhat like the Ural motor of the 70s. I've heard of Ural owners who 'blueprinted' their motors before the first start: fully balance the crank and flywheel, clean the swarf out of the crankcase, blow the grease out of the lubrication lines/oil galleries, replace main and big-end bearings, etc. Then do a really gradual run-in and regular oil changes with good oil. Some blokes are still on their original 70s engine, others have blown them up enough times to go the BMW conversion route.
Perhaps Punsuns should be treated like Urals and not Hondas? I'm also thinking of a sump extension and deeper oil pickup, windage plate (if it's not there), high pressure oil pump, etc. Is 3600rpm the sustained top speed, or should users stick to something lower? Synthetic oil? Beef up the crankcase? Throw away the case and transfer all the internals to a BMW or Guzzi (or Ducati??
) case?I don't like asking silly questions, but I'd rather ask them than buy an expensive boat anchor.
Dieselroo
Graham,
Im sure it wasnt your intention but non the less I feel a little insulted. Where from my posts over the last couple of years did you get the impression that I treated my engine like a Honda?
Or for that matter that Beckendorf the German builder that has had 3 Punsun cranks fail, is lacking in common sense also.
The engine recieved a thorough breaking in period, with extra oil changes during this period. Iam not from the old school kawasaki mindset of run em in quick.
I use quality oil which is Diesel specific and do not cut corners by using a petrol equivalent. I do not use a Fully Synthetic oil on ANY engine during bedding in. This is standard manufacturer advice on even the most modern engines as it impairs running in.
The Punsun engine has a smooth spot, ie it is balanced best at 3000rpm. Therefore I took the trouble and time to tune my transmission to ensure that overdrive engaged shortly before this, ensuring that I could cruise with minimum stress on the engine.
When the engine let go, I had just completed around 1000km in the company of Diesel Dave on his 10hp Enfield. Stressed the engine was not.
Regardless of this, 3600 is the design speed of this engine. I have spent a lot of time this week making enquiries and have found no reported cases of crank or case failures in industrial applications, where the engine is simply started and left to run, flat out, so to speak.
All the crank issues have been on the larger 22hp version, in a bike application, where we subject them to variable load throughout the rev range, clearly beyond there design specification.
It is my belief that when I mounted the engine, I over engineered the mountings. This was done to avoid the possibilitys of either frame damage ( a 10hp at the german rally had fractured its headstock) or mountings shearing ( a persistant Diesel Bike problem). This probably placed more strain on the engine than it was meant to handle. Hence the crank case crack. Rubber mounting must be the solution.
An expensive mistake indeed! However it must be remembered that to the very best of my knowledge, back in August 2006, I was the very first person to source this engine and begin a motorcyle conversion, although a german builder finished one first. Therefore I had no research and developement department and no body elses experience to draw from, unlike your good self.
By all means carry out all the balancing and enhancements that you suggest. They all make perfect engineering sense. However if you were to do this in the UK, unless you are privileged to have access to a comprehensive workshop, you will have spent far more than a quality Yanmar or equivalent would have cost to start with. Why then buy a budget engine? Whats the point?
I wish you well with your build and look forward to updates on your progress. I do however resent the implication that the pioneers whose experience is shared, and you are currently enjoying, are ham fisted or negligent in there approach.
Regards Mark
Im sure it wasnt your intention but non the less I feel a little insulted. Where from my posts over the last couple of years did you get the impression that I treated my engine like a Honda?
Or for that matter that Beckendorf the German builder that has had 3 Punsun cranks fail, is lacking in common sense also.
The engine recieved a thorough breaking in period, with extra oil changes during this period. Iam not from the old school kawasaki mindset of run em in quick.
I use quality oil which is Diesel specific and do not cut corners by using a petrol equivalent. I do not use a Fully Synthetic oil on ANY engine during bedding in. This is standard manufacturer advice on even the most modern engines as it impairs running in.
The Punsun engine has a smooth spot, ie it is balanced best at 3000rpm. Therefore I took the trouble and time to tune my transmission to ensure that overdrive engaged shortly before this, ensuring that I could cruise with minimum stress on the engine.
When the engine let go, I had just completed around 1000km in the company of Diesel Dave on his 10hp Enfield. Stressed the engine was not.
Regardless of this, 3600 is the design speed of this engine. I have spent a lot of time this week making enquiries and have found no reported cases of crank or case failures in industrial applications, where the engine is simply started and left to run, flat out, so to speak.
All the crank issues have been on the larger 22hp version, in a bike application, where we subject them to variable load throughout the rev range, clearly beyond there design specification.
It is my belief that when I mounted the engine, I over engineered the mountings. This was done to avoid the possibilitys of either frame damage ( a 10hp at the german rally had fractured its headstock) or mountings shearing ( a persistant Diesel Bike problem). This probably placed more strain on the engine than it was meant to handle. Hence the crank case crack. Rubber mounting must be the solution.
An expensive mistake indeed! However it must be remembered that to the very best of my knowledge, back in August 2006, I was the very first person to source this engine and begin a motorcyle conversion, although a german builder finished one first. Therefore I had no research and developement department and no body elses experience to draw from, unlike your good self.
By all means carry out all the balancing and enhancements that you suggest. They all make perfect engineering sense. However if you were to do this in the UK, unless you are privileged to have access to a comprehensive workshop, you will have spent far more than a quality Yanmar or equivalent would have cost to start with. Why then buy a budget engine? Whats the point?
I wish you well with your build and look forward to updates on your progress. I do however resent the implication that the pioneers whose experience is shared, and you are currently enjoying, are ham fisted or negligent in there approach.
Regards Mark
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roverthetop
- I luv the smell of Diesel...
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- Joined: Thu May 17, 2007 3:37 am
- Location: portland, oregon, us
graham,
the green kwaker i built is still on the road. Although i cannot attest firsthand knowledge of how she's actually fairing, as the owner is about 1200 miles away. i speak with him every now and again, with no reported problems- HOWEVER- he is not a mechanic. not even sure if he's changed the oil yet. also, being somewhat a novice motorcyclist, and now having medical issues, i'm sure he probably hasn't had her motoring much lately. As for my harley builds, the auto sporty- very similar to fiddlers- is... WAS almost finished. i have decided to pull the engine and make some adjustments in the wake of fiddlers catastrophe.
Fiddler,
Your knowledge and helpfulness with my builds has been invaluable. i can only hope that you are planning another build for us to banter about. it's my opinion, having emailed with you quite a bit, that you know what you're doing. although i'm saddened the engine blew, i appreciate the research it provided immensely.
general punsun quality-
in this arena its my belief that it is "good" for what its designed for. not great. but we here are throwing it in to situations its not been designed nor tested for. we are the test. having now worked with 4 of these, i can attest that they are ALL different in their workings. seems quality assurance is lacking. all 4 of mine have had different quirks, different rocks, different shakes, even different sounds. seems a roll of the dice on what you'll unpackage. i have had the luxury of 3 being broken in at the same time, to be able to see firsthand the oddities of each side by side.
i'm now pondering a generator application in an austin healy. electric drivetrain with a genset. let the punsun run as intended. i have 1 engine not yet spoken for. the other 2 are the harley auto sporty and softail 6er applications. i will finish those and put them on the road, patiently awaiting what seems inevitable. time will tell.
apologies for the longwindedness.
brett
the green kwaker i built is still on the road. Although i cannot attest firsthand knowledge of how she's actually fairing, as the owner is about 1200 miles away. i speak with him every now and again, with no reported problems- HOWEVER- he is not a mechanic. not even sure if he's changed the oil yet. also, being somewhat a novice motorcyclist, and now having medical issues, i'm sure he probably hasn't had her motoring much lately. As for my harley builds, the auto sporty- very similar to fiddlers- is... WAS almost finished. i have decided to pull the engine and make some adjustments in the wake of fiddlers catastrophe.
Fiddler,
Your knowledge and helpfulness with my builds has been invaluable. i can only hope that you are planning another build for us to banter about. it's my opinion, having emailed with you quite a bit, that you know what you're doing. although i'm saddened the engine blew, i appreciate the research it provided immensely.
general punsun quality-
in this arena its my belief that it is "good" for what its designed for. not great. but we here are throwing it in to situations its not been designed nor tested for. we are the test. having now worked with 4 of these, i can attest that they are ALL different in their workings. seems quality assurance is lacking. all 4 of mine have had different quirks, different rocks, different shakes, even different sounds. seems a roll of the dice on what you'll unpackage. i have had the luxury of 3 being broken in at the same time, to be able to see firsthand the oddities of each side by side.
i'm now pondering a generator application in an austin healy. electric drivetrain with a genset. let the punsun run as intended. i have 1 engine not yet spoken for. the other 2 are the harley auto sporty and softail 6er applications. i will finish those and put them on the road, patiently awaiting what seems inevitable. time will tell.
apologies for the longwindedness.
brett
dnepr lombardini 854cc convert
kwaker punsun vtwin convert (SVO as well)
harley sporty (cvt and SVO) done
harley softail (SVO) 6 spd in the works
kwaker punsun vtwin convert (SVO as well)
harley sporty (cvt and SVO) done
harley softail (SVO) 6 spd in the works
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Anorak_ian
- I luv the smell of Diesel...
- Posts: 549
- Joined: Tue Dec 19, 2006 7:21 pm
Mark, I'm so sorry to hear of your problems, such a nice looking bike and you have obviously put in a shed load of hard work.
I was going to buy one of these engines for my new project, a 1960's Royal Enfield interceptor (buying most of the parts tomorrow); I think I may go another route with the engine now though. Maybe two ruggerini 500cc single engines one in front of the other, I dunno.
Was the punsun a copy of a Yanmar? If so I wonder how they would compare on the bench, maybe the crank cases on the punsun are weaker than on the yanmar, maybe getting an old nail of a yanmar and using the cases is the way ahead for this engine.
Again sorry to hear of your probs.
Ian
I was going to buy one of these engines for my new project, a 1960's Royal Enfield interceptor (buying most of the parts tomorrow); I think I may go another route with the engine now though. Maybe two ruggerini 500cc single engines one in front of the other, I dunno.
Was the punsun a copy of a Yanmar? If so I wonder how they would compare on the bench, maybe the crank cases on the punsun are weaker than on the yanmar, maybe getting an old nail of a yanmar and using the cases is the way ahead for this engine.
Again sorry to hear of your probs.
Ian
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smokyjoe
- I luv the smell of Diesel...
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- Joined: Mon May 26, 2008 1:42 am
- Location: Western Taxachusetts (Massachusetts) USA
roverthetop- Forget my query on the other board (pintohorse), you've answered my question quite well, thank you!
While only having a little experience "on the run-in bench" with my Hatz E79, one thing I have noticed about this engine that may be pertaining to many of these stationaries. It can run all day at max 3,000 RPM, and will idle down to just ticking over (but don't want to oil starve it) and it is really smooth, well not quite, I'll say as smooth? as a Harley knucklehead with the stock cam.
But there are, what I can see, at least 2 RPMs that the thing will gyrate and cause the heavy steel welding bench it is bolted onto to start walking down the driveway! The engine has all kinds of balance weights and a balance shaft but my guess is that it was only balanced at max RPM and some strange combination of balance and resonance comes into play somewhere in between full throttle and idle.
I am thinking of using some firm urethane auto suspension bushings for mounting but don't know how the CVT belt will hold out. There shouldn't be much movement but don't know until I try. It has about 1 inch of aluminum in the crankcase where the mounts bolt and the factory mounts are 2-1/2 inch by 3/8 thick angle iron. I am thinking now of certainly not mounting it completely rigid as was done in the vibratory roller it came out of.
Thanks to y'all your insight and sharing your ideas and designs. I figure the more I look at what is already done is going to make my build much easier and better than if I went it alone! Thanks again.
While only having a little experience "on the run-in bench" with my Hatz E79, one thing I have noticed about this engine that may be pertaining to many of these stationaries. It can run all day at max 3,000 RPM, and will idle down to just ticking over (but don't want to oil starve it) and it is really smooth, well not quite, I'll say as smooth? as a Harley knucklehead with the stock cam.
But there are, what I can see, at least 2 RPMs that the thing will gyrate and cause the heavy steel welding bench it is bolted onto to start walking down the driveway! The engine has all kinds of balance weights and a balance shaft but my guess is that it was only balanced at max RPM and some strange combination of balance and resonance comes into play somewhere in between full throttle and idle.
I am thinking of using some firm urethane auto suspension bushings for mounting but don't know how the CVT belt will hold out. There shouldn't be much movement but don't know until I try. It has about 1 inch of aluminum in the crankcase where the mounts bolt and the factory mounts are 2-1/2 inch by 3/8 thick angle iron. I am thinking now of certainly not mounting it completely rigid as was done in the vibratory roller it came out of.
Thanks to y'all your insight and sharing your ideas and designs. I figure the more I look at what is already done is going to make my build much easier and better than if I went it alone! Thanks again.
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pietenpol2002
- I luv the smell of Diesel...
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- Joined: Wed Dec 05, 2007 6:56 pm
- Location: Goshen, IN USA
I had a couple of random brain stem firings in response to your posting Smokyjoe. Your concern regarding any impact on the CVT belt from rubber mounting the engine could be solved by attaching the jackshaft directly to the engine, thus avoiding any negative interaction between the gyrating engine and the fixed jackshaft. The smaller Comet CVT's have a plate the bolts to the engine which maintains the jackhaft bearing in constant relationship to the crankshaft. Variations between the jackshaft and the rear wheel sprocket can be managed by a spring loaded tensioner much like those used on many dirt bikes.
And does Mark's recent experience with the Punsun argue for the use of a manually controlled variator? To do so would allow the engine to operate at a constant rpm as per the designer's intent, while allowing the speed to be contolled by the variator.
Cheers,
Ron
And does Mark's recent experience with the Punsun argue for the use of a manually controlled variator? To do so would allow the engine to operate at a constant rpm as per the designer's intent, while allowing the speed to be contolled by the variator.
Cheers,
Ron
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Graham Stitz
- I don't post much...
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- Location: China
Re: Punsun Kaput
Geez, Mark, I sounded like a bit of a wanker, didn't I? Comes from opening mouth before engaging brain - common habit. It really wasn't my intention to cast nasturtiums at the pioneers who know more about the topic than I ever will. In no way were my comments designed to suggest that you (or anyone else) is a ham-fisted boy racer on a yamazukihonki pocket rocket. I'm really sorry if I came across as a wheelchair expert.
After seeing Punsun information on the forum, I was disappointed to read that your project sh*t itself - at least for the short-term. I have a question: why the need for head braces when Guzzis and Dukes are able to do without them - does it have to do with crankcase rigidity or orientation - or is it a 'diesel thing'?
You've been thorough in areas I didn't even know existed, Mark, and I've taken note of quite a number of your responses. My 'Honda' comment pertained to some diesel operarors who suggest max design revs as much as possible and others who operate on 80-90% of max revs and no higher. Is this a good idea, or does it neglect 10-20% of what's available? I better shut up, read others' posts and learn some more before I change feet again.
Cheers
Graham
After seeing Punsun information on the forum, I was disappointed to read that your project sh*t itself - at least for the short-term. I have a question: why the need for head braces when Guzzis and Dukes are able to do without them - does it have to do with crankcase rigidity or orientation - or is it a 'diesel thing'?
You've been thorough in areas I didn't even know existed, Mark, and I've taken note of quite a number of your responses. My 'Honda' comment pertained to some diesel operarors who suggest max design revs as much as possible and others who operate on 80-90% of max revs and no higher. Is this a good idea, or does it neglect 10-20% of what's available? I better shut up, read others' posts and learn some more before I change feet again.
Cheers
Graham
Dieselroo
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andrewaust
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Sorry to hear about the engine cracking mate! Bloody hell, it seems to have gone in a big way quickly too 
I've also notice it's up for sale which is a damn shame as you put a lot of time and effort into the bike.
Where's that dude who was posting adverts everywhere on the forum to buy the V-Twin, wonder if he could do something.
Did the engine have any guarantee Fiddler? It doesn't seem right that you have to wear the engine failure. In my view it doesn't matter if the heads where supported or not, the engine casing shouldn't fail like that. Gen-sets, Harvesters and hydraulic pumps etc that these types of engines power can put a lot more stress then sitting one in a motorcycle.
It just doesn't seem right you have to loose out!
Cheers
I've also notice it's up for sale which is a damn shame as you put a lot of time and effort into the bike.
Where's that dude who was posting adverts everywhere on the forum to buy the V-Twin, wonder if he could do something.
Did the engine have any guarantee Fiddler? It doesn't seem right that you have to wear the engine failure. In my view it doesn't matter if the heads where supported or not, the engine casing shouldn't fail like that. Gen-sets, Harvesters and hydraulic pumps etc that these types of engines power can put a lot more stress then sitting one in a motorcycle.
It just doesn't seem right you have to loose out!
Cheers
Ian,
Its my understanding that the Punsun is a rip of the Yanmar but I couldnt confirm that they are identical. Worth keeping an eye out though.
Smokey/Pietenpol
Seems to me that it would be necessary to ensure the crank and jackshaft maintain the same relationship. I think it would massivley accelerate wear on both the belt and friction faces otherwise.
I think this would be a first for us. Someone needs to get on and do it to provide feedback.
Graham,
No worries, sometimes the written word doesnt carry the meaning you intend. Ive done it myself on here before
With regards to your queries about engine mounting, the Punsun is a crude unit with no internal counterbalancing.
It appears that the Punsun is designed to be naturally balanced somewhere around its intended opertating speed, about 3000rpm, meaning it is poorly balanced elsewhere. Fine in an industrial application but motorcycle designers have different design criteria from the start. No one would buy or tolerate a bike this crude, at least not for the last 40 years since the Japanese upped the anti with refinement, forcing the British to use isolastics.
Also when Guzzi/ Ducati design an engine, they know exactly where it is going and can factor in mounting points/ bracing/ case strength from the start.
When you buy an industrial engine you get 2 mounts, very close together, right in the middle, at the bottom of the engine, using only 4 bolts, hardly ideal for our needs.
To give you an idea of the vibration, I had a visit at work from an Occupational Health, Hand Arm Vibration specialist. He placed specialist vibration monitoring equipment on all my tools and gave a safe daily use figure. My 2 stroke stuff came out around 2 hours use, 4 stroke stuff between 2 and 8 hours depending on quality and Grinders/ Sanders etc could be used all day.
Not one to miss an opportunity we rigged up the bike and did some test runs. The vibration was the equivalent to riding a pneumatic drill!! 14 minutes max daily use!! Thats a lot of stress on 2 little mounts. I have all the data if anyones interested.
Other Diesel specific problems exist such as increased mass of pistons compared to petrol counterparts but Im starting to ramble. I think you get the picture why I deemed it necessary to support this engine as best as I could. All the other builds using a Punsun at the German Rally had followed a similar approach so I wasnt the only person thinking along these lines.
Hope that helps. With regards to your other question about whether to run at max output or 80%, why not start a new thread? Might generate some discussion.
Andrew,
No guarantee with the engine as it was an ex test unit. The supplier however has been brilliant once more. He has another ex-test unit that he is going to strip and pass the casings on .
I'm looking forward to stripping the lump, see if it can give us any other clues to why it let go.
Cheers, Mark
Its my understanding that the Punsun is a rip of the Yanmar but I couldnt confirm that they are identical. Worth keeping an eye out though.
Smokey/Pietenpol
Seems to me that it would be necessary to ensure the crank and jackshaft maintain the same relationship. I think it would massivley accelerate wear on both the belt and friction faces otherwise.
I think this would be a first for us. Someone needs to get on and do it to provide feedback.
Graham,
No worries, sometimes the written word doesnt carry the meaning you intend. Ive done it myself on here before
With regards to your queries about engine mounting, the Punsun is a crude unit with no internal counterbalancing.
It appears that the Punsun is designed to be naturally balanced somewhere around its intended opertating speed, about 3000rpm, meaning it is poorly balanced elsewhere. Fine in an industrial application but motorcycle designers have different design criteria from the start. No one would buy or tolerate a bike this crude, at least not for the last 40 years since the Japanese upped the anti with refinement, forcing the British to use isolastics.
Also when Guzzi/ Ducati design an engine, they know exactly where it is going and can factor in mounting points/ bracing/ case strength from the start.
When you buy an industrial engine you get 2 mounts, very close together, right in the middle, at the bottom of the engine, using only 4 bolts, hardly ideal for our needs.
To give you an idea of the vibration, I had a visit at work from an Occupational Health, Hand Arm Vibration specialist. He placed specialist vibration monitoring equipment on all my tools and gave a safe daily use figure. My 2 stroke stuff came out around 2 hours use, 4 stroke stuff between 2 and 8 hours depending on quality and Grinders/ Sanders etc could be used all day.
Not one to miss an opportunity we rigged up the bike and did some test runs. The vibration was the equivalent to riding a pneumatic drill!! 14 minutes max daily use!! Thats a lot of stress on 2 little mounts. I have all the data if anyones interested.
Other Diesel specific problems exist such as increased mass of pistons compared to petrol counterparts but Im starting to ramble. I think you get the picture why I deemed it necessary to support this engine as best as I could. All the other builds using a Punsun at the German Rally had followed a similar approach so I wasnt the only person thinking along these lines.
Hope that helps. With regards to your other question about whether to run at max output or 80%, why not start a new thread? Might generate some discussion.
Andrew,
No guarantee with the engine as it was an ex test unit. The supplier however has been brilliant once more. He has another ex-test unit that he is going to strip and pass the casings on .
I'm looking forward to stripping the lump, see if it can give us any other clues to why it let go.
Cheers, Mark
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roverthetop
- I luv the smell of Diesel...
- Posts: 94
- Joined: Thu May 17, 2007 3:37 am
- Location: portland, oregon, us
great news! that's the bloke to deal with for sure! what a wonderful opportunity to strip her down and see the workings firsthand.
any bits you want machined, send me specs and i'll see what i can do!
b
any bits you want machined, send me specs and i'll see what i can do!
b
dnepr lombardini 854cc convert
kwaker punsun vtwin convert (SVO as well)
harley sporty (cvt and SVO) done
harley softail (SVO) 6 spd in the works
kwaker punsun vtwin convert (SVO as well)
harley sporty (cvt and SVO) done
harley softail (SVO) 6 spd in the works
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Diesel Dave
- Site Admin
- Posts: 1016
- Joined: Sat Dec 02, 2006 1:21 am
- Location: Essex, UK
- Contact:
Single Crank Breakages
I've had a bit of an email exchange with Mike Siebert in the states, he built a mini-bike using the single cylinder Yanma chineese clone motor.
Even though this was just 6Hp and driving through a kindly Comet 20 series CVT he did suffer a crank breakage with less than 10 hours use.
Again the failure was similar to the V2 crank failure we saw in Hamm - at the big end pin close to the flywheel.
It's a real shame it was a really nice little bike too.
Dave
Even though this was just 6Hp and driving through a kindly Comet 20 series CVT he did suffer a crank breakage with less than 10 hours use.
Again the failure was similar to the V2 crank failure we saw in Hamm - at the big end pin close to the flywheel.
It's a real shame it was a really nice little bike too.
Dave
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Diesel Dave
- Site Admin
- Posts: 1016
- Joined: Sat Dec 02, 2006 1:21 am
- Location: Essex, UK
- Contact:
Crank Failures
From the Punsun in Hamm it looked like a combination of undersized design of the central crankpin, and the effects of welding the flywheel to the crank fatiguing the metal.
There may be an issue over matalurgy and choice/quality of the steels used.
I still maintain that their timing may be too far advanced causing too much piston knock - especially on pick up from idle - they do clatter a lot at this point.
Variable timing would help but until this is available in stationary diesels......
There may be an issue over matalurgy and choice/quality of the steels used.
I still maintain that their timing may be too far advanced causing too much piston knock - especially on pick up from idle - they do clatter a lot at this point.
Variable timing would help but until this is available in stationary diesels......
-
Zem
- I luv the smell of Diesel...
- Posts: 46
- Joined: Fri Sep 26, 2008 8:11 pm
- Location: Vienna
- Contact:
Hi Mark, Good to see you home.
Especially the hack with the refrigeration unit was cool! Are you able to show some pictures from the pipe.
Do you have the 812cc or the 836cc engine?
As far as I understand, the crankcase is broken in the on the side of the engine where the throttle control is located, right?
This is a picture of my 836cc engine... the arrows are showing the parts where the crankcase differs to the 812cc engine. In 812cc these rests where much smaller.
best regards
Hans
Especially the hack with the refrigeration unit was cool! Are you able to show some pictures from the pipe.
Do you have the 812cc or the 836cc engine?
As far as I understand, the crankcase is broken in the on the side of the engine where the throttle control is located, right?
This is a picture of my 836cc engine... the arrows are showing the parts where the crankcase differs to the 812cc engine. In 812cc these rests where much smaller.
best regards
Hans
--
May the Source be with you!
May the Source be with you!
OK, Punsun stripped and all is not well inside, excuse the poor photography but it gives you an idea.
First up, there is no thrust washer between the side casing main bearing and the crank. This means that the cog that drives the cams has picked up on both the bearing face (okish) and the ali case ( not ok).
Should there be a thrust washer here to prevent this? Also I had a massive amount of crank float, about 6mm! Is this normal or the cause of the cog rubbing?
The big ends are well on there way to being shot, as is the main bearing. Premature wear by either ali contamination? And/or fuel contamination as the fuel pump appears to have been leaking somewhat into the case although not so bad that the oil level rose.
No swarf has ever been found in the filters or oil which is why I suspect that its bits of ali that have done the damage. Oil changes have been frequent.
Neither is the crank a particularly snug fit in the other bearing. Am I being too picky for an industrial engine or does this all smack of very poor quality.
Shovelhead
Pictures of the mounts as requested, they simply bolt to the engine and the standard bike mounting points, rear mount includes jackshaft for cvt.
Pictures of the crack ive highlighted with marker pen. Its very obvious that this engine has been welded before, probably at the factory as a result of poor casting.
Zem, not much to photograph regarding the repair. It was simply swopping one high pressure pipe for another and bending it a lot to make it fit.
Do you have a thrust washer between crank and casing on yours? Mines the smaller 812 unit.
Any thoughts most appreciated, Mark
[img=http://img530.imageshack.us/img530/4749 ... zs4.th.jpg][img=http://img530.imageshack.us/images/thpix.gif]
[img=http://img510.imageshack.us/img510/254/ ... vx7.th.jpg][img=http://img510.imageshack.us/images/thpix.gif]
[img=http://img530.imageshack.us/img530/8189 ... wm9.th.jpg][img=http://img530.imageshack.us/images/thpix.gif]
[img=http://img510.imageshack.us/img510/4606 ... bt6.th.jpg][img=http://img510.imageshack.us/images/thpix.gif]
First up, there is no thrust washer between the side casing main bearing and the crank. This means that the cog that drives the cams has picked up on both the bearing face (okish) and the ali case ( not ok).
Should there be a thrust washer here to prevent this? Also I had a massive amount of crank float, about 6mm! Is this normal or the cause of the cog rubbing?
The big ends are well on there way to being shot, as is the main bearing. Premature wear by either ali contamination? And/or fuel contamination as the fuel pump appears to have been leaking somewhat into the case although not so bad that the oil level rose.
No swarf has ever been found in the filters or oil which is why I suspect that its bits of ali that have done the damage. Oil changes have been frequent.
Neither is the crank a particularly snug fit in the other bearing. Am I being too picky for an industrial engine or does this all smack of very poor quality.
Shovelhead
Pictures of the mounts as requested, they simply bolt to the engine and the standard bike mounting points, rear mount includes jackshaft for cvt.
Pictures of the crack ive highlighted with marker pen. Its very obvious that this engine has been welded before, probably at the factory as a result of poor casting.
Zem, not much to photograph regarding the repair. It was simply swopping one high pressure pipe for another and bending it a lot to make it fit.
Do you have a thrust washer between crank and casing on yours? Mines the smaller 812 unit.
Any thoughts most appreciated, Mark
[img=http://img530.imageshack.us/img530/4749 ... zs4.th.jpg][img=http://img530.imageshack.us/images/thpix.gif]
![[img=http://img530.imageshack.us/img530/4749 ... zs4.th.jpg]](http://img530.imageshack.us/my.php?image=enginestrip007zs4.jpg){kind=link}
[img=http://img510.imageshack.us/img510/254/ ... vx7.th.jpg][img=http://img510.imageshack.us/images/thpix.gif]
![[img=http://img510.imageshack.us/img510/254/ ... vx7.th.jpg]](http://img510.imageshack.us/my.php?image=enginestrip012vx7.jpg){kind=link}
[img=http://img530.imageshack.us/img530/8189 ... wm9.th.jpg][img=http://img530.imageshack.us/images/thpix.gif]
![[img=http://img530.imageshack.us/img530/8189 ... wm9.th.jpg]](http://img530.imageshack.us/my.php?image=enginestrip014wm9.jpg){kind=link}
[img=http://img510.imageshack.us/img510/4606 ... bt6.th.jpg][img=http://img510.imageshack.us/images/thpix.gif]
![[img=http://img510.imageshack.us/img510/4606 ... bt6.th.jpg]](http://img510.imageshack.us/my.php?image=enginestrip015bt6.jpg){kind=link}
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taildraggin
- I luv the smell of Diesel...
- Posts: 80
- Joined: Mon Dec 31, 2007 2:11 am
- Location: Suffolk, New York USA
Fiddler: it appears you have your answer. It suggests to me that, if using the Punsun (or any clone), it should be torn down and gone over to be sure that it's constructed properly.
The 10hp LA100 Yanmar I found (that UPS rolled here from Utah) was torn down yesterday. The previous owner claimed 1000hrs on it, and from it's state, that sounds within reason. Inside, it seems just broken in, in typical japanese fashion. I will replace the rings and lap the valves only because it's open. If I can get the case repaired, we'll have something. Quality is very good.
Ebay occasionally lists the water-cooled Yanmar V-2s new for $1750 (Kipor clone is this model). http://cgi.ebay.com/18HP-Yanmar-Diesel- ... dZViewItem
(There are 2 versions and most are the vertical shaft operation model - needing conversion to horizontal. Note oil dipstick, etc.)
That obvious stuff said, the Punsun is a neat engine and as it is air-cooled and inexpensive, well suited. I hope they can be made reliable without too much cost or effort.
Regarding vibration/mounts, most manus locked down the rear mount and rubber mounted the front and head stay, allowing the engine to 'pivot' around the rear mount. This maintains the final drive relationship allowing the engine some damped fore&aft motion.
You may already know about Lord mounts http://www.lord.com/Home/ProductsServic ... fault.aspx. They have all of the rubber mount types that you may want and can easily be incorporated into our frames. This site in Oz has a good description: http://www.fdrive.com.au/products/04/engine.php
G'luck with your rebuild. You've gone so far with that bike, it would be a shame to toss her now.
- Charlie
The 10hp LA100 Yanmar I found (that UPS rolled here from Utah) was torn down yesterday. The previous owner claimed 1000hrs on it, and from it's state, that sounds within reason. Inside, it seems just broken in, in typical japanese fashion. I will replace the rings and lap the valves only because it's open. If I can get the case repaired, we'll have something. Quality is very good.
Ebay occasionally lists the water-cooled Yanmar V-2s new for $1750 (Kipor clone is this model). http://cgi.ebay.com/18HP-Yanmar-Diesel- ... dZViewItem
(There are 2 versions and most are the vertical shaft operation model - needing conversion to horizontal. Note oil dipstick, etc.)
That obvious stuff said, the Punsun is a neat engine and as it is air-cooled and inexpensive, well suited. I hope they can be made reliable without too much cost or effort.
Regarding vibration/mounts, most manus locked down the rear mount and rubber mounted the front and head stay, allowing the engine to 'pivot' around the rear mount. This maintains the final drive relationship allowing the engine some damped fore&aft motion.
You may already know about Lord mounts http://www.lord.com/Home/ProductsServic ... fault.aspx. They have all of the rubber mount types that you may want and can easily be incorporated into our frames. This site in Oz has a good description: http://www.fdrive.com.au/products/04/engine.php
G'luck with your rebuild. You've gone so far with that bike, it would be a shame to toss her now.
- Charlie