CB350 tranny + Yanmar L100 ... How I did it

[mazdog355]

Many people are wondering how I used the original 5 speed trannsmission from a 1972 Honda cb350 in my dieselbike, seeing how the factory eingine and tranny are one integrated unit.

I have lost many of the original pictures i had while i was building the bike, so bear with me.

So, In a nutshell, the first thing I did was to cut the cylinders off the original cb350 engine\tranny combo using a sawzall. the next steps were to modify the frame so the engine would fit, mount the diesel engine, etc.


I hate pull start...at least it works every time.




Stretched frame...two inches makes a big difference.

The Engine and tranny are linked via a #40 chain, The sprockets being a 48t and a 24t. This gives the bike a primary drive ratio of 2:1 (obviously), which is considerably taller than the factory 3.62:1. It's actually geared too high because i do most of my cruising on 4th gear (I use 5th for downhill sprints and with the wind...lol). The chaincase and tranny are both lubricated by synthetic 75w90.


adjustable tensioner, as long as you have a die grinder and a welder.

The 48t sprocket is attached to the clutch basket with four 5/16" bolts through four nuts that are welded to the original gear on the basket. I did that so i can replace the sprocket if necessary. There is a chain tensioner on the slack side.I actually had a problem with the tensioner coming loose (another story), but so far it's been pretty reliable after almost 1000 miles.




Sorry 'bout the dirt, i ride a lot of back roads

I hope this sheds some light on the project, any questions...just ask.





But, know this, I am not finished. After seeing the article about the turbo Enfield Taurus, I realize that's the next step...Boost

http://cgi.ebay.com/ebaymotors/RHB31-Tu ... _832wt_759

[LocomotiveBreath]

You should also mention and others take note, your engine is a reverse running engine, one that runs clockwise verse normal counter clockwise. I didn't see it mentioned in this forum. I noticed it right off the bat on the YouTube video, good job.

By the way, the turbo you mention in the above post is the same turbo I have on my Ruggerini/Honda, also standard on the Briggs & Stratton 3LC Diesel (Daihatsu).

Dave

[mazdog355]

This engine turns CCW, just like most engines. That's why i put the tensioner on top...less stress.

[LocomotiveBreath]

Your right, I never knew the gear box reversed direction, wow, I learned something. It makes sense now as it was gear drivin, reversing direction. Your engine does run in a reverse direction from normal, back to the drawing board.

Thanks

[mazdog355]

Yes yes, I learn new things every minute...

[andrewaust]

Interesting post mazdog! I wondered what jap engines could be cut to obtain the tranny for use with the diesel. You've matched it all up really well.

It would be interesting what total gear ratios turn out to be, some have suggested using a 19 tooth on my bike, but I'm sure it will over gear the capacity for the engine to pull and because it's a bugger of a job to change sprockets I've been reluctant to try it.

Cool



A

[coachgeo]

anyone got pics of the engine/tranny complete like the one he disected. Hard to picture what he ended up with out knowing what it looked like before disecting.

[Crazymanneil]

Did you have to cut the side off the box and then weld a plate on? I love the primary case btw with the little welded nuts in.

N

[sbrumby]

I am glad someone else noticed the engine running backwards I thought I was looking at pictures reversed. I did not know any engines were made to run clockwise, who makes the engine?

[roodesign]

looks like a normal engine to me, CCW rotation, it's just mounted in the frame, reversed...primary drive on the right...not the left...that's why the chain tensioner is on the top run of the chain...original drive for that tranny would have been with a gear, likely...so it makes sense that's my 2cents...Roo

[mazdog355]

to andrewaust:
I imagine you could do it to a number of different bikes if you wanted, but someone gave me this the donor bike for free, so i used what i had...

coachgeo:

Here's some pics i just took today of some more cb350 engines i have laying around:





Crazymanneil:

The chaincase is designed to bolt onto the tranny where the original clutch cover was mounted using the original bolt holes on the tranny (and i added some for strength). It's all sealed off and in oil ...well, it leaks a little.

sbrumby:

Roo is absolutely right, CCW rotation, nothing special about this engine

[andrewaust]

Yes I can understand the CCW as if you were able to place a gear drive between output shaft to clutch/transmission input shaft, you would have the engine rotating clockwise and the clutch running counter clockwise as per normal engine transmission arrangement with the original engine setup. Because you have used a chain drive you need the engine output shaft to rotate in the same direction CCW as the clutch "or transmission input shaft".

I like the way you have done the conversion, jap transmissions are much nicer in shifting, smoothness and reliability then some of the others. I like my Enfield box, but been spoiled by so many others.



Bugger! Hope this makes sense - just blame it on sleep deprivation !!



A

[mark_in_manchester]

No-one has mentioned cutting up unit-construction 2-stroke engines yet, to use the gearbox. The advantage would be that the crankcase is separate (for under-piston fuel-air compression) so potentially easier to cut off, although the gearbox and primary drive usually share oil supply which would still need careful thought and appropriate sealing to the outside world. I'm into eastern-block 2 strokes - MZ250 would be tricky since primary drive is by gear and clutch is on crankshaft. MZ125/150, and Jawa/CZ use primary chain, so this might be a better place to start. Dead Jawas are free in UK...
Mark, Manchester

[pietenpol2002]

This might be a stretch, but let's have a go at it. What if we maintained the entire 2 cycle crankcases and crank. Obviously remove the rod, and bolt a plate at the base of the bore. Then weld a plug between the crank throws and grind the big end journal away leaving essentially a straight shaft in lieu of the crankshaft. Replace the stock crank bearings with sealed bearings since they will now be absent a source of lubrication and maintain a seal on the primary drive side of the shaft leaving the oil bathed primary undisturbed.

On the stator side remove the rivets from the stator hub and bolt/weld to the hub a taper lock bushing to which you can attach any size/ratio of cog belt pulleys driven by your power source, much like the this stator-side driven supercharger.

http://www.utvblog.net/wp-content/uploa ... er-004.jpg

I would however mount the stator hub drive pulley as close as possible to the engine to avoid excessive overhang loads, which one could do with a stator such as this.

http://img.photobucket.com/albums/v41/b ... 06_img.jpg

Most 2 cycles however have an outboard hub which would preclude the use of a taper lock hub, requiring one to perhaps bolt the pulley directly to the hub.

http://i233.photobucket.com/albums/ee10 ... CN2804.jpg

And the the stator cover could then be notched to accommodate the forward driven belt.

Unquestionably, it would be a heavier "transmission", but would avoid tampering with the the oily environment of the primary case. Even so.............. seems like a lot of work just to get a gearbox, but then we Yanks don't have access to the range of independent transmissions as found in the UK and EU. Such deprivation leads us to these desparate delusions.

Ron

[mark_in_manchester]

Hi Ron -
I'd thought along those lines - and thought that perhaps the gearbox could be stood on-end (with dummy crankshaft above it) to save 'length' in the machine. The other way would involve making a crank extension to the diesel engine which is identical to drive-side crank of 2-stroke engine, and letting this protrude through drive-side mainbearing and oil seal which would be retained from MZ or Jawa engine. Problem then would be that diesel unit would almost certainly end up way over to one side in the bike frame!

M.

[sbrumby]

Its all been done before lads.

[Sphere]

Well, then you shouldn't have been so shy about it

You can find (left for) dead CBs easily, might be nice to know more about the specifics of this type of conversion.

Its all been done before lads.

[mazdog355]

Very interesting... I wish i had found this site before i started my diesel conversion.

[Sphere]

Just get cracking with that turbo

[Crazymanneil]

Unquestionably, it would be a heavier "transmission", but would avoid tampering with the the oily environment of the primary case. Even so.............. seems like a lot of work just to get a gearbox, but then we Yanks don't have access to the range of independent transmissions as found in the UK and EU. Such deprivation leads us to these desparate delusions.

Ron

Check out the Ultima (et. al) transmissions -

http://www.ultimaproducts.com/drivetrains.html

Theres a few others out there including genuine Harley transmissions too. And then they bolt straight on to Harley or BDL etc clutches with Harley starter motors etc. You can buy hydraulic actuator plates for these setups and also semi-auto ball bearing clutches. Theres tons of stuff for them and you are practically tripping over them in the US. Buying process for a clutch in UK has been a somewhat slow process for me so far but seems like a decent setup so far.

N

[BoxerOtto]

hey guy's here's what ive got going on, not mobile yet so no data to reveal, perhaps one day.

[andrewaust]

hey guy's here's what ive got going on, not mobile yet so no data to reveal, perhaps one day. http://img36.imageshack.us/my.php?image=dsc01495f.jpg http://img524.imageshack.us/my.php?image=dsc01494h.jpg http://img197.imageshack.us/my.php?image=dsc01456w.jpg http://img44.imageshack.us/my.php?image=dsc01455l.jpg http://img530.imageshack.us/my.php?image=dsc01454q.jpg http://img14.imageshack.us/my.php?image=dsc01451m.jpg

Looks like things are going along really well Boxer! Cool

The Japanese tyranny's are so compact and very reliable most of the time, making a really good box unit if you can adapt them as been the case by others on the thread.




A

[BoxerOtto]

thank's andrew, i really can't wait to take this thing for a spin,but you know, LIFE!!! anyway now my imageshack thing seems to be working i'll try to keep a little more up to date.it's a kawasaki kdx 175 transmission with six well spaced gears. if you turn the former crank shaft 8.5 times the countershaft goes 1 in first gear and in sixth works its way to 2.25 to one. should be plenty low for taking off. it's geared 2 to 1 up from the motor so at 3600 it's turning 7200 just like the kdx used to.capped off the cylinder area and is just an oil well for the bearings now. i'm going to try an automotive style tensioner under the belt and scince these pictures it also has a buffer to keep the engine from twisting under load.

bye for now Otto.

[coachgeo]

hey guy's here's what ive got...

Can you get a shot of mostly engine/tranny combo. Those pics are so small its hard to tell much.

[BoxerOtto]

here we go again, computers! hopefully these pictures come out larger. my edit of my first post didn't seem to work for re inserting larger pics. http://img36.imageshack.us/img36/3223/dsc01495f.jpg http://img524.imageshack.us/img524/5248/dsc01494h.jpg http://img197.imageshack.us/img197/9778/dsc01456w.jpg http://img44.imageshack.us/img44/8593/dsc01455l.jpg http://img530.imageshack.us/img530/8268/dsc01454q.jpg http://img14.imageshack.us/img14/4698/dsc01451m.jpg

[BoxerOtto]

Nope that didn't work. Try try again just like bike building.

[BoxerOtto]

let's give this a go, a few closer tranny engine shots. http://img196.imageshack.us/img196/9914/dsc01369w.jpg http://img44.imageshack.us/img44/3686/dsc01368q.jpg http://img19.imageshack.us/img19/7675/dsc01350cfg.jpg http://img132.imageshack.us/img132/3677/dsc01349d.jpg http://img34.imageshack.us/img34/5150/dsc01370gcp.jpg http://img197.imageshack.us/img197/7682/dsc01347dcv.jpg http://img44.imageshack.us/img44/9177/dsc01388g.jpg

[coachgeo]

Thanx

[mazdog355]

Awesome job on the KDX tranny Boxer, I wish i had thought of that... And I like the idea of the 2:1 Primary belt drive, with the larger pulley on the engine, the V-belt should have no problem holding the load. I was thinking about running a primary V-belt but didn't think it could handle it since my setup is a 2:1 ratio geared down from the motor.

Mazdog

[BoxerOtto]

no problem, but don't take this as a problem free solution. this is just my way of mounting it in and is still an unproven concept. i make changes as i go along but fairly confident i can make it work. it helps to have machining & welding capabilities on site. its the lack of time that keeps it from getting finished.
there are many solutions to come to the same end, some work,some work well,and some may not work as thought.keeping it simple should keep the bike reliable and easy to work on and service.this is why this site is so great for sharing ideas and experiences.

cheers, Otto.