Well this might be the shortest build thread... unless I get some inspiration tonight while I sleep on this build
I came across a KX500 dirt bike rolling chassis that was prime for re-powering. Someone had cut out the engine basket... making it useless. I figured it would be a tight fit but being that the frame was already cut it was ready to be modified.
I ordered up a motor and it arrived this afternoon. After taking it out of the box... I knew I was in trouble. This thing is huge!
Tonight I pulled the exhaust and fuel tank and made an attempt to line them up the best I could. These two stroke frames are short! I still have to fit a transmission... argh!
Dont know what your worried about mate its nearly done ! Well its too early to give up anyway, I (very limited experiance in these matters) would jack up your engine and transmission right up into the frame leaving about a 10mm gap but at the same time bring it back towards the swingarm as much as you can, then align up the sprockets taking into account the final drive chain hitting the swingarm with its massive travel, I would then wrap some frame around it an see how it looks, forget completely how the original frame loop looked, its about to get bigger ! Have a good look at the build threads here, its something we've all had to deal with.
Looking more hopeful this morning. I did some trimming and the motor is up where it should be. I'm hoping to fit an Enfield 5 Speed in here someplace... it hasn't arrived yet so I don't know the exact dimensions. It appears that I'll likely need to stretch the frame a few inches to make it all fit. Does anyone have the yanclone + enfield length so I can know if I'm getting close. Any recommendations as to the best method to stretch this frame a little? I'd like to use the stock tank and seat when done.
I took a couple pictures. The first one has the motor way forward... which isn't ideal but may lend some space for the gear box. The second photo shows the motor where I'd like it... with no space for a gear box
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Motor forward... less wheel travel and I'd need to trim the fender.
After playing with the layout I decided to install a GTC TC2 Torque Converter (TAV2 clone) that I had. I simply don't have the space to put the 5 speed without lengthening the frame I figured I'd need to grind a little, maybe drill some new holes... no such luck, the kit mount is too short. After trying a 100 ways to make it fit... I conclude a new plate and a second shaft would be needed. I hate kits that don't fit. I cut out a basic design and checked the fit on the bike. Now to make some shafts and bearing housings.
Hi Forhire, I can vouch for that exact same torque converter from the exact same supplier and it works great, although I haven't used it for more than a couple of runs, had a bit of a nightmare getting it over to the UK though.
Just re-read your thread, are you making a new Mounting plate for your CVT ? If so have a look at my thread, I didn't need to take of that much at all to make it fit, is your engine a copy of the 300cc yanmar ?
Dougy wrote:Just re-read your thread, are you making a new Mounting plate for your CVT ? If so have a look at my thread, I didn't need to take of that much at all to make it fit, is your engine a copy of the 300cc yanmar ?
The motor is the 186F which is a clone of the L100 Yanmar I believe. It's sold as a 10 hp. Originally I planned on using the 300cc but opted for the larger 400cc... this is causing me some issues. I looked at your pictures yesterday and simply couldn't understand how you fit the TC2... now I understand .
After I cut out the mounting plate I was able to better visualize everything. The adapter plate required a larger belt as it increased the center distance about 3 inches (75 mm). I still had clearance issues running the chain to the lower jackshaft... If I ever broke a chain it would take out the injection pump or the line.
Today I decided to try an different approach. I moved the jackshaft chain to the front... much more complex... but it might work. Nothing behind the plate. I also rotated the driven pulley vertical above the shaft. I'll bring the pulleys home tomorrow so I can render them... with some luck and a big chuck of aluminum this will work
I downloaded the engine model from my work computer and inserted the adapter model. I might not be clearing the exhaust. I guess I'll need to take some measurements tomorrow.
Forhire wrote..
The motor is the 186F which is a clone of the L100 Yanmar I believe. It's sold as a 10 hp. Originally I planned on using the 300cc but opted for the larger 400cc... this is causing me some issues. I looked at your pictures yesterday and simply couldn't understand how you fit the TC2... now I understand .
I'm glad I could help a bit mate, I've got the 300 cc yanmar engine so can't help you with the clone sizes, by the looks of them drawings you've done there your gonna be ok .
Is the center-to-center distance on the stock unit too short to tuck the driven shaft in the notch of the engine by the pump? If you can, could you run the driven shaft and jack shaft on out to the right of the engine and use a cog belt to drive them. If you're making room behind the engine for the drive sprocket to the rear wheel, you'd also have room to run a cog belt arrangement or even V-belt from driven shaft to the jackshaft (quiet and not requiring lubrication). When you speak of a broken chain taking out the pump, are you talking about a chain from the driven to jackshaft. Or are speaking of the final drive chain to the rear wheel.
One concern is that increasing the distance between the CVT pulleys requires a new CVT belt that is only available in limited lengths. And even though the additional jackshaft and accompanying drives rob power, you plans for this bike don't include pushing a lot of wind. Should have plenty avaialble to tackle the off-road.
pietenpol2002 wrote:Is the center-to-center distance on the stock unit too short to tuck the driven shaft in the notch of the engine by the pump? If you can, could you run the driven shaft and jack shaft on out to the right of the engine and use a cog belt to drive them.
I redesigned everything this morning. The previous design interfered with the exhaust There isn't much room behind the plate... it's a tough angle to get to the jackshaft around the motor housing. I like the belt idea. How wide of a belt would be required do you think? I'd have to add an idler... maybe I can fit a spring tensioned idler.
pietenpol2002 wrote:One concern is that increasing the distance between the CVT pulleys requires a new CVT belt that is only available in limited lengths. And even though the additional jackshaft and accompanying drives rob power, you plans for this bike don't include pushing a lot of wind. Should have plenty avaialble to tackle the off-road.
I found the correct length belt before I moved the driven pulley... it was only $26. I've gone back to the stock length is the latest design.
I'm still playing with ideas. Here's the latest render. I added the TC2 pulleys for scale.
Isn't this CVT? I'll definitely let you know how it works.
I am a little confused too actually now that I read more. I thought a torque converter was more like an old go cart clutch on end and a set pulley/sprocket size on the other. What I read now is that once past idle they (T.converter and CVT) seem to operate in same conceptual way with two pullys who change size; thus ratio. Here is a bit I found on the differences.
http://buggynews.com/cvt-vs-torque-converter-t1818-10.html wrote:the main differences between a cvt and a torque converter is this. a cvt has clutch pads in the driven pulley. it also keeps the belt under tension constantly. if you look at a cvt under operation you'll see that as soon as you start the engine the belt is rotating. when the rpms get high enough the centrifugal clutch grabs (inside the secondary sheave) and you go. then when even higher rpms are achieved the rollers squeeze the primary(driving) sheave causing the belt to climb to the outer edge of the sheave. which also causes the belt to overcome the spring in the secondary(driven) sheave and go towards the center. If you watch a torque converter during operation you will see that when you start the engine the belt does not move. the primary sheave is open far enough so that the belt is not being driven. it's just resting on the spinning hub of the sheave. when you apply more rpm the sheave starts to close, grabs the belt and away you go. from that point it performs the same as a cvt. the primary sheave has what is called cams or pucks(usually 3 of them) which act pretty much the same as the rollers in a cvt. the more rpm the more it forces the belt to the outside of the primary and towards the inside of the secondary. as far as advantages go between the two I dont know what they are. they pretty much seem to do the same job. I think a cvt is supposed to be smoother. for use on scooters and such on the street. the torque converter setup seems to be more jerky on take off. which provides a better holeshot and tire spinning starts. I'll bet offroadkarter has no problems with quick take offs. my two cents
coachgeo wrote:I am a little confused too actually now that I read more. I thought a torque converter was more like an old go cart clutch on end and a set pulley/sprocket size on the other. What I read now is that once past idle they (T.converter and CVT) seem to operate in same conceptual way with two pullys who change size; thus ratio. Here is a bit I found on the differences.
I appreciate your research. If I understand... basically the torque converter and the CVT are very similar and the terms are frequently interchanged (likely wrongly). So the CVT's driven pulley has a clutch, which engages at RPM. In addition to being smoother as you mentioned, I suspect the belt life or wear would be much better. Anyone have a link an affordable true CVT?
pietenpol2002 wrote:If you can, could you run the driven shaft and jack shaft on out to the right of the engine and use a cog belt to drive them. If you're making room behind the engine for the drive sprocket to the rear wheel, you'd also have room to run a cog belt arrangement or even V-belt from driven shaft to the jackshaft (quiet and not requiring lubrication).
I have been playing with some belt designs using Gates Design Flex. One of the main issues is the limited space and short center to center distance. My first choice would be synchronous (cog) but they all require at least a 2.5 inch pitch diameter, 3 inch is more practical to carry the intermittent loading. If it wasn't a 1:1 drive it would be easier. My next choice would be a PolyFlex JB. These are similar to a micro-v but better. I can easily carry the load with a pair of 1.5 inch sheaves using a 5M belt. It is amazing the load these belts can carry. I guess I'll need to rework the drawings and see how a belt works
I was hoping to keep the original 6.75 inch center distance and use the original mounting plate by simply remaking the aluminum jackshaft quill from steel. Today I decided to remove the quill and see how everything looks. No joy. I guess I'm back to the longer center distance.
Here are some pictures to save anyone the trouble of trying it yourself
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Jackshaft quill. Red Loctite took some muscle.
Bolted position interferes with the cylinder.
Floating position would require new mounting holes but it interferes with case and fuel line.
Bolted horizontal position interferes with the case. It also is very close to the foot peg.
I had ordered an Enfield 5 Speed brand new from a guy in India off Ebay. It was suppose to take a month or so to arrive. So I have been playing with the torque converter option. Well the transmission arrived last Friday. This thing is a bit larger than expected
I guess I'll be saving this for my next build. The dirt bike is much too small for this setup. Figured I'd post a couple photos... maybe this will help anyone else thinking of putting this combo on a dirt bike.
I figured I'd need to grind a little, maybe drill some new holes... no such luck, the kit mount is too short. After trying a 100 ways to make it fit... I conclude a new plate and a second shaft would be needed. I hate kits that don't fit. I cut out a basic design and checked the fit on the bike. Now to make some shafts and bearing housings. 
I'm glad I could help a bit mate, I've got the 300 cc yanmar engine so can't help you with the clone sizes, by the looks of them drawings you've done there your gonna be ok 