Punsun HD chopper

[bearnyc]

Hi All, I've been lurking here for a while. I've finally made some progress on my build so I'll start a thread. Thanks to all on this forum who've shared their experience, and to those who've answered my emailed questions. Started it for the first time last night. Exhaust, wiring, shift linkage needs to be sorted(before I can ride it), but here's a video of it running(on commercially produced B99 biodiesel):

http://www.youtube.com/watch?v=60QWByhbz-k

It's a Paughco frame(Harley aftermarket) that we cut the tube between motor and transmission and created a "Y" for clearance. Motor is a Punsun from a portable generator that had a tapered output. We had to cut and tap the taper and CNC an insert to fit the Primo from primary pulley. The motor has rubber mounts on the bottom and a head steady on the top. It rocks front and back, but not side to side.

[Sphere]

Very nice Whitewalls on a diesel, what WERE you thinking

[coachgeo]

... The motor has rubber mounts on the bottom and a head steady on the top. It rocks front and back, but not side to side.

Interesting thank you.

What is a "head steady"

What is the OEM purpose of the rubber mounts you used? Those made for generators or come from something automotive orrr?

Did you hard mount the tranny? Do you think you will need a spring armed belt tensioner on your belt drive to take up slake from rubber mount engine and solid mount tranny?

[Stuart]

Nice one Bear I've printed off a picture and will show it to Whisker's (Punsen Harley) when I see him at Brightona on Sunday (he's not got the web) as yet. I'm sure he will be impressed.
So far he's done about 800 miles on his machine and not without the odd problem. Last I heard he had some diesel get into the sump but I think he's on top of that now. I don't think his engine is rubber mounted as he thinks this could accentuate and vibration problems known to some of those engines.

[bearnyc]

The Punsun was in a portable generator when I met it. It had braided stainless exhaust sections and SOFT rubber mounts(pic attached). The exhaust is still on the bike(with pipes flipped around). I plan on keeping the flex parts of the exhaust in the final setup. The Punsun rocked a LOT in the generator. My rubber mounts are generic industrial mounts from Mcmaster http://www.mcmaster.com/ . After other's horror stories of Punsun's blocks cracking, and the fact that it came to me rubber mounted I felt like it might be best to go that route. I'll take a shot of the head steady today and post it. It's a piece that connects the tops of the jugs to where the HD ignition used to mount to the frame. Transmission is rigid mounted and alignment on the belt seems to be fine. The Harley motor vibrated plenty and the belt drive system allows for wiggling, and may help isolate some of the vibration, at least that's the theory.

[bearnyc]

Here's a pic of the "head steady". Motor rocks forward and back, but not side to side, keeping the belt alignment ok.

[Stuart]

Gotcha, that looks like it will do the job
Stuart
PS: Didn't see Whiskers to show him your bike build as he was too hungover to make the show

PSS: But he did see it another time and liked it lots

[bearnyc]

Rode it today. It took a year and a half to reach this point. Here's a link to a(slow loading) shot of it moving:

http://web.mac.com/bearschmidt/bike/fly.html#0

Still have a lot of little things(doesn't shift properly, exhaust is still from the generator, have to start it with jumper cables... ...) but I'm quick to jump on a bike once it moves!

I'm curious about the huge amount of black smoke. I had it running on commercial B99 biodiesel, then put in pretty much straight D2 petrodiesel and had no change in the smoke...LOTS(see the video) It smokes under load and when increasing the revs. Does anyone have suggestions on any adjustments or steps to address this?

I'm looking at various exhaust options, and a friend suggested that most motorcycle silencers have fiberglass or something similar in them and that the(huge amount of) particulate in the exhaust would quickly stop this from reducing sound as it clogged it up?? Any experience with this or suggestions on motorcycle silencers with all solid parts inside that actually reduce the noise level?

Thanks!

[Sphere]

Hi Bear,

I've taken the liberty of uploading your MOV to Youtube, so more people will have access. Let me know if this is a problem.

http://www.youtube.com/watch?v=cHdpao0_ElU&fmt=18

[dieselbikin]

I had the same problem with my L100 Yanclone smoking heavily under load. If your throttle assembly is similar then reading all the way through post https://www.dieselbikeforum.com/view ... f=21&t=753 may help.

[Crazymanneil]

Loving the vid! I have also heard the fibreglass exhausts clog up with particulates from a diesel engine from another (4 wheel) dieselhead. The race pipe I had for my 600 bandit was the fibreglass packed type which wrapped round a pipe made of mesh which ran up the middle (if that makes sense). Having said that, getting plugged up would not have made that exhaust much louder...

N

[bearnyc]

thanks for the advice about the smoking. I'm looking forward to attempting adjustments. Mounted my inexpensive air filters today. Found a "mechanical baffle" silencer on JC Whitney, but it was too long. It had no glass and was the right price. Still looking...

[bearnyc]

Got the exhaust started today. Here's a pic of Peter working with the flexi bits that were part of the generator's exhaust and then the final layout.

[jeremy]

Hi-- Perhaps everybody but me is savvy to this, but I learned the hard way that engines produced to run generators are factory-governed for "static-speed' behavior (commonly at the top end of their rpm range), and the power plants we require for vehicular propulsion are built-up to run at variable speeds. I was told that the run quality will be poor when you try to get power out of one of these static-speed governed engines at typical low-rpm startup speeds. Your (and my) unit has been engineered to do something quite different than what we're asking it to do, and won't be correct until you break it down and reconfigure the governor to match those built for variable-speed applications. This means finding someone to supply you with the different parts you'll need to do it, plus the manual describing the process if you're lucky. This is what I went through with my german Hatz, and it took some perseverance. Sad news I know, but I hope it helps resolve the poor combustion...

[bearnyc]

"dieselbikin" I have to say MANY THANKS for the link in the thread above. I finally got around to performing the adjustments described in the thread in your post. It worked like a charm. The bike only smokes if you really crank it open quickly now. There's plenty of power for riding, now I'm playing with new sprokets and gear ratios. I'm sure a variable gov would add power, and be more graceful, but this works fine for me. I have a friend who is working on producing variable govs for the Punsun motors and will post our progress. The bike is fun to ride and is everything I'd imagined. I posted some newer pics to http://www.dieselchopper.net Thanks again for everyone's help on this site. Now I find myself pricing Smart motors...

[Sphere]

Looks nice... but doesn't your bike need a front brake?

[bearnyc]

After 3 years I thought I would post a follow up.

Yes...I did eventually add a front brake. I rode it for a few thousand miles and enjoyed the frame cracking in half on the top tube under the tank and both supports we welded in the "Y" section between the motor and transmission.

We used thicker steel and got it back on the road.

It really ran well. I eventually added a Baker 6 into 4 transmission and could go 90MPH.

Recently it was running fine and then suddenly lost power. It appears that the Punsun blew. It still runs, but horribly. I found that the crank itself it wrecked, or the crank bearings are shot. You can rock the flywheel/crank back and forth. It is amazing it runs at all.

I haven't taken it apart yet to be sure, but this is what I know so far.

I got my hands on two Longfar motors that looked identical to the Punsun, except they have keyed 1" output shafts instead of the tapered one on my Punsun. It will require a new pulley insert. Then I realized that the Longfar motors also have different motor mounting points(vertical instead of horizontal holes) so it will need new motor mounts too.

Ahhh fun.

[iron_monkey]

Can you list here the adjustments you did? Its not really clear from this thread what 'adjustments' they were.

thanks

[coachgeo]

So what total number of miles did you get out of the Punsun?

When you crack it open......... see if you can determine if an add on support bearing on the end(s) of the crankshaft (either side or both?) would have potentially extended the life of the engine.

[bearnyc]

Finally getting around to putting the pig back together. "Iron_Monkey" the adjustments I referred to were just changing the fueling screw. Nothing extreme, just adjusted for smoke.

The Punsun died due to the crank splitting in HALF right in the middle. I forgot to take a pic of it, but will and will post it. It is bizarre that the motor still ran afterwards.

I'm not sure how many miles I put on it(no speedo). Guessing maybe 5k. I really don't know though. Not a lot.

I had 2 Longfar motors that I ordered, hoping they would drop in. They have "feet" cast in the block(I didn't know this) so the mounting to the frame is different from the Punsun(no feet on block).

The crank was removed from one Longfar, but it is not the same as the Punsun.

So....the decision was made to change the frame mounts to adapt to the new case design of the Longfar motor. Theory is that the rubber mounting on the Punsun caused stress on the crank and killed it.

Longfar is now solid mounted to the frame with a new head steady without joints. Maybe the vibration will be miserable. Maybe it will destroy itself without rubber mounting. One way to find out.

Next step is to make a new insert for the front pulley(Longfar is a keyed 1" output and the Punsun was a taper).

[klondikekid]

Good to hear your build worked out for you, I haven't ridden mine yet, so hearing that your bike worked so well i making me feel much better. Have you thought about a turbo? mines a GT15 off e bay, aprox. $200.00 new.

[coachgeo]

Finally getting around to putting the pig back together. "Iron_Monkey" the adjustments I referred to were just changing the fueling screw. Nothing extreme, just adjusted for smoke.

The Punsun died due to the crank splitting in HALF right in the middle. ....

Now that I'm deeper into my build and gained more knowledge, maybe the best bet, especially with the China Clones is to build in a Side load bearing on the flywheel end where the belt or chain attaches to engine. For example in design for the my Tiger; plan is to mount to a cage... made to look like protection/crash bars or something to that affect, will be a bearing that the last portion of the Stub Shaft will ride in outside of the CVT pulley that will be there. This Cage/crash bar will be attached to engine not bike frame thus it will move with the engine (rubber shock mounted). The Kubota we are using has seemed to hold up in other bikes without crankshaft issues but since there really is no side load bearing built into the engine block, am putting one in for longevity purposes.

Just something for you to mull over in your design ideas if you haven't got her up and running fully already.

[bearnyc]

Klondike_kid that is my kind of bike! I do want to put a turbo on it...once I have it moving again. It was reasonable fast off the line before(rideable) and could do over 80MPH(plenty fast on a chopper).

Side load bearing is a good idea. In the long run maybe a Japanese motor is even better... I just have these lying around.

I received this PM from a friend and am curious for people's thoughts:

"There was another dieselbike member who did the same
with a punsun engine and the engine cracked right at the
base of the engine cylinder."

Curious for people's thoughts?

My top tube cracked in half last time and both tubes between the motor and transmission(frightening). I used very thick tubing on the vertical tubes this time and repaired the top tube. Part of the idea of the solid "head steady" top brace was to support the top tube/prevent the thing from cracking in half.

Thanks

[coachgeo]

...
I received this PM from a friend and am curious for people's thoughts:

"There was another dieselbike member who did the same
with a punsun engine and the engine cracked right at the
base of the engine cylinder."

Curious for people's thoughts?

My top tube cracked in half last time and both tubes between the motor and transmission(frightening). I used very thick tubing on the vertical tubes this time and repaired the top tube. Part of the idea of the solid "head steady" top brace was to support the top tube/prevent the thing from cracking in half.

Thanks

Punsun from what I have read is slowly improving in build quality "slowly. The older the engines.... the more design flaws. For a good while there were casing problems..... then quality went up and that issue lessened. Then there were crankshaft problems..... quality improved and that issue seems to have lessened of recent, etc etc etc.

As to cracking... diesel bikes since they vibrate more tend to create issues with metal fatigue not found as often in other instances. Just found this. Might help some

http://reliabilityweb.com/index.php/art ... rts_crack/

[bearnyc]

Finally got the motor in and running. Actually seems to vibrate less than the rubber mounted Punsun. Maybe this Longfar has better balance.

I need to finish the primary.

Vid of it running on B100:

http://www.youtube.com/watch?v=jpDqZDG6DZA