Torque Convertor input..

[Rick]

Ok, I've got the frame tacked togther. The engine is sitting in it loosely. Before I go much further, I've got some decisions to make.
Since I can't seem to find a reasonably priced transmission on this side of the pond, I'm pretty much locked into a torque convertor.
I've been looking and talking with anyone I can find. I've got the room to stick about anything in there. When I built the frame, I left plenty of room.
This is going to be a light weight bike. Low, rigid, and only 6 hp. I once looked at the Comet TAV2 unit which is rated for 8 hp (2 stroke/4 stroke)

Today,. I called Comet directly and talked with "Don" at technical assistance. Told him exactly what my plans were and gave him my concerns. (For those that don't know, Comet makes LOTS of stuff for OEM and aftermarket manufacturers) They know their stuff, and custom design a lot of clutches, etc...
I specifically asked if the TAV2 would handle the job. He said "Absolutely! We over build these things. They'll handle 10 hp pretty easily. " I specifically asked about putting it on a diesel. "He said they have a "lot of small diesels running around with them."
The only reservation he had about it was making sure the engine would run up to 3600, and that it was geared low enough as to not burn out the clutch when starting out. Said virtually all failures of their stuff was due to overheating the clutches.
Sure would make thing simpler. I like the idea of having the driver/driven parts mounted together. Even if I don't go with the TAV2, I will probably rig up something similar, only bigger in size..

input?

[balboa_71]

Rick,
Don at Comet is right, starting out puts the biggest strain on both friction clutches and Comet CVT drive units. I went with the expensive 500 series and bought from mfgsupply.com (best pricing I could find on the net).

http://www.mfgsupply.com/GoMiniClutchTo ... d=ErsG44eF

These guys stock some of the parts, but can order direct from the factory.
IMHO, the Comet 30 series is a bit light. With the 500 series, you can buy spring and roller kits to customize your drive unit to perform the way you want it to (thats what I did). Also, I'd go with a minimum of 9-1/2" between drive and driven units as you will have trouble accessing your engine controls due to the close proximity of your jackshaft bearings to the throttle linkage. I went with 9-1/2" but could have gone another inch. Of course, your frame will dictate distance as well as your engines starter hangs out front and can hit frame rails/tubing.

Last, I geared my bike low because I drive in the city and do a lot of starting and stopping, the drive unit takes less of a beating this way.

Cris

[LocomotiveBreath]

My input, I'd look at the Comet 700/800 series. I talked with Comet a year or two ago and they sent me to Quality Drive here in CA.

Quality Drive
1709 South 9th Street
Alhambra, California 91803

(They set my Clutch and drive pulley). And with our applications and limited RPM range of a Diesel, they sugested the 700/800 & 1190 series would be ideal, room for larger hp applications farther down the road. Note one of the features over the 500 series is "Wide Ratio"
http://tinyurl.com/ykckvx

Also look at what Team Industries has to offer in a drive pulley. Look at the Rapid Reaction pulley.
http://tinyurl.com/yc6o9w



Just my input.
Dave

[boneshaker]

I've got a little 211cc launtop that i'm planning to put in a bike shortly. I picked up a barely used Torq-a-verter (believe it's the same as the TAV2), and am planning to use that. I was just making sure it would fit last night. The mounting holes line up just fine, but the built in jackshaft sticks out just a little too far on the back, and bumps into the "throttle" assembly. (i don't know what else to call it... where the Start/Stop switch is) I think if i cut a little notch in the sheet metal, it'll fit just fine though.



I know it seems like a small engine, but i'm going for a small bike. Something like they made in the early 1900s. More of an engine strapped to a bike frame type thing. Not expecting to get great speed out of it, but VERY good MPG.

A couple of my "inspirational" photos

[Kenco1955]

Hi there,
I'm new to this forum, so would just like to say Hi to all diesel fanatics out there!!
I have had a long time interest in the possability of building a diesel powered bike for some time now and would like to share a few thoughts and ask a few questions, they are as follows;
Whilst I am by no means knocking the people out there that have used small industrial diesels in their projects, I do feel that this is the wrong type of engine to use, my reasons for this thinking is as follows. These engines are primarilly designed to opperate efficiently at just one narrow rev range (to drive a generator, cement mixer etc.) We as motorclclists need our motive source of power to opperate at as wide a range as possible.
Car manufacturers have spent millions of pounds developing diesel engines to do just that!! Automatic advance of injection, cam profile etc etc.
Also the price of a second hand car engine is often a lot less than a small industrial unit!!
Add the power that a small automotive unit develops to the equation and surely this must be the way to go??
Now for the down side, SIZE, there's no getting away from it, these things are large (in a very big way!!)
Which brings me to my next question.... Transmission.
I like the idea of CVT (who wouldn't??) But is such a unit available from the likes of "comet" that would reliably handle the sort of power a car diesel can produce?? (typically 60-90bhp) and of course the torque!! I have pulled comet's web site up and they do have clutches and torque converters that can handle up to 150hp, but these are designed for snowmobiles using two stroke engines, how would they perform on a high torque 4 stroke diesel?? and would they be reliable for several thousand miles with minimum maintenance??
If anyone has any knowledge of any of the points raised I would be most interested to listen to there views.
Kenco1955.

[andrewaust]

Hi Kenco


Welcome to the forum and thank you for posting up your questions.

At the moment industrial engines are the preferred option, mainly from what you have actually commented on - size etc.

These engines are sometimes reasonably priced, with some of the China clones under $500 for a 406 - 440 single. I think the V twin clone goes for around $1300 USD, not bad for a new diesel.

Some of the guy's have also made some great bikes using 2-3 cylinder diesels, some with Turbo charging, giving a good power to weight ratio.

The actual power curves for high-speed diesels are similar, whether for automotive or industrial use. The torque curves are usually between 1800 - 2400 rpm for small high-speed diesels, stated maximum power at around 3600rpm. Some engines will go slightly higher to around 4200rpm.

A lot of diesel industrial engines give a max hp at 3000 - 3600 rpm as this is a preferred rpm setting for the machinery it bolts to - mainly generators - why Most electric generators run at these speeds to get the 50 - 60 hertz that is needed to match grid power - this can also be found with power stations running steam turbines. They run at a speed of 3000 rpm.

Fuel consumption is best for most H/S diesels around the 2000rpm mark.

Some of the newer industrial engines are going electronic common rail injection, using the same technology as its transport cousins - most meeting strict pollution requirements.

I don't have as much experience with CVT's as other guy's on the forum, but by what I have read, they are a good choice for many applications.

I think the guy's have a play with the actual clutch mechanism weights etc to lower the rpm rate at which they engage, as you've seen, some clutches are for 2 stroke engines that engage at high rpm's - no good for a diesel.




Cheers

Andrew

[Kenco1955]

Tanks for the reply Andrew,
Yeah, I know what you mean.
Perhaps a geared jack shaft to initially raise the effective output RPM of the slow reving diesel may be a way round utalising a "comet" type clutch and torque converter (designed for two stroke engine speeds)???

Cheers, Ken

[LocomotiveBreath]

Ken you made me laugh, thank you. Now you go get your car engine and show us how to do it the right way.

Just a note: Industrial engines power the fastest, most dependible, and the most powerful machines and vehichles on the planet, automotive engines are the cheaper throw away counterparts that industries sell to the general public, then the public replaces them every other year so they can buy the new model with the new fangled chrome gas cap cover.

Dave

[Kenco1955]

Read your reply with interset Dave, and have gotta say that if I were building a generator, water pumping station or anything els that wasn't going to move, then my choice too would be an industrial engine, as I'm not then I feel that the automotive route (LBS/HP??) is still the best way to go.
I unfortunately do not have the means of doing this easilly or cheaply, that being the reason why I joined this forum, to exchange ideas with like minded enthusiasts.
Thanks for taking the time to reply though.
My hat's off to anyone who grafts a diesel engine into a bike frame, whatever the type of engine.
Regards to all.
Ken

[Anorak_ian]

Kenco1955 take a look at the video, I think the car engined bike is the fast silver bike with sidecar. I think its a smart car engine? Anyhow, if I didn't have a generator engine I would be on the look out for a smart car engine or similar, in fact I'm thinking of building another bike in the future using one, best get the one I have on the road first lol .

http://video.google.co.uk/videoplay?doc ... pr=goog-sl

[Kenco1955]

Thanks for that Ian.
Yeah, that sure looks like a whole lotta fun, glad to see this guy takes safety seriously and has his air bag inflated just in case!!! LOL
I must admitt I like the idea of a three wheeler, and the possibillity to mount a transverse engine over the sidecar wheel would possibly be an answer to the chair wheel lifting problem??? (better weight distribution and all that sort of stuff!!)
Good luck with your project, let me know how it progresses.
Thanks again.
Ken

[jeremy]

Hey Rick, I spoke to "Don" as well, and he recommended the "Model 500" for my application--a light bike with a Hatz 1B30 <7Hp. mill. That was the only one he specified, so I purchased it (at around 600 bucks!) and it sure looks like it can handle the task. Now I'm wondering why he gave me a different recommendation than he gave you...did you look at the mod. 500? he says it is a good choice due to the ability to "tune" it to engine's peak output by ordering different pucks and springs. Also able to adjust the engagement RPM with separate kits. That all sounded good to me, so I bought it. What did you find out about the TAV model that made it seem like the right choice?

[balboa_71]

Jeremy,
I'm running a 500 series Comet behind my 10hp clone and am using both a spring and weight kit(s) to lower engagement speed to 1,400 rpm which works pretty well. My total weight (bike and driver) is around 650/700 lbs.
I can give more details if you need it.

Cris

[Rick]

Let me clarify things a bit.. Don did not "recommend" a TAV@ (modle 30) to me. I asked him about it. He said it would be strong enough for a 6 hp diesel.
Two reasons I'm planning on it are it's CHEAP! (like me) and it offers a wider drive ratio than the others; actually making it an overdrive at hi speed. I have a roto tiller with a 6hp gas engine. I run the snot out of it, and it still has the original drive belt after over 20 years.

[jeremy]

Thanks Cris, I just responded on another thread, didn't check here. Sooo, what about my 347cc. Hatz 1B30 with a lowly 6.8 HP I think--am I going to need to drop that engagement point as you did? You can add this to my other question about final drive ratios, if you will. I really appreciate your feedback in this area, I'm still coming up on theory. J

[jeremy]

...And Thanks to Rick as well for the clarification. I forgot to add that my all-up weight should be around 425 lbs, incl. me. - J

[balboa_71]

Jeremy and Rick,
What I did with my Comet 500 drive unit was install the heaviest weight kit they offer, and went to the next weaker springs which provides an engagement speed of 1,400 rpm (they provide a chart showing part numbers for both their spring and weight kits and how the effects engagement speed).
I could have just gone to an even weaker spring kit, but by using the heavy weights, the unit upshifts quicker after engagement. My clone engine ticks over at around 1,300 rpm so any lower engagement, and I'd have trouble stopping IMHO, if you leave the drive unit stock, it will engage at 2,100 rpm, which is well above where usable torque comes into play, and you will waste your drive belt quicker due to higher amounts of friction between drive pullies and belt. As it works out, engagement is quick and easy (this equals less slippage between pullies and belt, which is the achilles heal of Comet drive systems).
With that said, I'm using a #50 plain Jane chain (nice rhyme , 1" jackshaft, 16 tooth drive and 80 tooth driven sprocket. Yes, this is low gearing, but 55mph is all that I want to see. To be quite honest, going fast on a homebuilt motorcycle scares the hell out of me as my welding skills are not the best, in addition, by removing the stock engine/gear box, and putting in my own drive train, the bike is no longer "balanced from the factory" for a lack of better terms. Suzuki bikes (GS series) and many other Japanese bikes from that era are noted for having a "hinge" in the middle of the frame (term used to describe poor handling characteristics)
and I can tell you that crashing from a "tank slapper" sucks (happened to me once at 70mph out on the freeway )

Cris

[jeremy]

Cris, Thanks for taking the time, your info was valuable. Sounds like I ought to do as you have, and drop the engagement rpm. After I wrote last, I ended up chewing on the simple final-ratio formula that presents itself with but a moment's cogitation. Based on what I could remember of the CVT ratios and a 26" guess at tire O.D., I came up with a 5:1 reduction, jackshaft-to-wheel which would give me adequately slow engagement speed so as not to burn things, and a modest but acceptable top end potential of around 60 mph, based on the slight overdrive of the CVT and the 3600 rpm. max of the Hatz, or approx. 4000 at the jackshaft. This is not the 7:1 that "Comet Don" advocates, and I don't know how to reconcile that. But I did notice that coincidentally or not, it's just what you're running. And Ditto on the speed sphincter--I'm just trying to get to work righteously cheap, and survive it! Thanks again--jeremy.

[sbrumby]

Does anybody know of any conversions done with this type of drive but instead of useing the centrifugal clutch mechanism useing a regular clutch. The reason I ask this is because my Yam with the ruggerini in pulls off at tickover & it will pull off in 1st 2nd or 3rd. So in the latest project I am looking at the various options but I dont want to waste 2000rpm before anything hapens.

[Rick]

Well, after a little time away from the shop.. (It was pretty muck buried in snow) I'm back on the project. Decided to go with a Comet 40 series convertor. I started adding up the cost of using a TAV2, and the labor necessary to adapt it, and found it'd end up being more than a 40 series. Especially when I got one from eBay. I was bidding on a 500, but it went a little higher than I wanted to go. Ordering the pillow blocks (bearings/mountings) later today.
Once I get the drivetrain roughed in, I can finish the welding on the frame, and get it back on wheels...

[Diesel Dave]

Sam, you asked if it was possible to use a normal clutch with a CVT.

You can get the CVT to be perminantly engauged, there is a garter spring on the 40/44 series bob weights, if this is removed the clutch won't disengauge the belt.

Attaching a bike clutch to the other end would need a bit of inginuity but I'm sure you could do this.

Modern scooters use a similar setup, the belt drive is always engauged to the motor but there is a centrifugal clutch at the tail end - similar to a drum brake with weights forcing the shoes out when the revs rise.

There are commercial centrifugal clutches available but I havn't found one up to the job, given the torque rating of my 10hp and then multiply this by the cvt ratio and you need a big clutch. I was going to make up my own with a mini brake drum but the amount of work is great and I can't swing a piece of metal large enough in my 3" lathe to make the backplate.

I'm gonna see how well the belts last on the Comet 44, and might try the 700 as it has a much wider range. Getting these systems to engauge early is an easy matter of increasing the bob weights in the primary clutch. In my scooter racing days I would make my own super lightweight ones to allow the motor to rev to it's full 14,500 rpm - you have to be prepared to re-ring the motor after every race though.

Good to hear from you though - see ya in June.

Dave