Reposted pocketbike and lawntractor transmission ideas

#1
Just curious if anyone has ever tried mounting a "pocket bike" transmission to an engine on a minibike to be used in place of a torque converter or jack shaft?

Also, I had an idea involving a lawn tractor gearbox. (Doubt it would work, but I had to share). I have "access" (gotta go dig it up some, it sunk in the mud, haha) to a "small" vintage lawn tractor gearbox. It's a Tecumseh/Peerless 1200, 3-speed w/ reverse in the H-pattern. I think it had been attached to a small Ford lawn tractor at one time.

I began to think about how I could cut off some of the axle shaft length, leaving the gearbox (gotta figure out how to seal the ends though), and use it as a pseudo-jackshaft. I thought about how if I did something like this, I could run power from the minibike engine to the input shaft on the gearbox, and then from the gearbox, through one of the axle shafts to the rear sprocket. My logic is that I would be able to have different gear ratios at hand for different applications, whether it be on the road or going down through the woods/swamp, where I would be prone to wanting to crawl along without burning up my centrifugal clutch. I think the input shaft is on the side instead of the top, so it could possibly work for a horizontal shaft engine setup.

I still have to measure it to see if it fit in the first place though.

Going to delete the other post I made in the Engines and Mods section.
 
#3
It probably is easier, but in some ways, that's what got me into doing this minibike project in the first place, the challenge of it all.

I guess what it comes down to, I enjoy being able to tinker and and make adjustments, and see if something works or not. I think the lawn tractor transmission would be fun because I could put it in one of three gears and and depending on the need, have the choice of opting for torque when crawling around muddy/sandy/gravelly roads (my backyard is swampy), or being able to switch to a higher gear when on the driveway or side yard to pick up speed.

I know the TAV essentially covers that whole area, but having some parts on hand seems to make the thought of doing something unique or different very tempting to try. I'm sure everyone would think I'm a bit :eek:ut: for wanting to try that, haha.
 
#4
You can build whatever you like really, no rules. I will say that pocketbike stuff is best used for miniature bikes like Tom Thumbs and clown bikes. Lawn tractor stuff has been done with mixed success, depends on the engineer really. I like traditional drive systems but have long considered making a mount for a vertical shaft engine and use a 1 to 1 45 degree gearbox from McMaster Carr but that's high rent so I though a twisted green belt to a jackshaft with a clutch mounted to it and out to the wheel from it. I find running mowers for nearly free. I'd like to have one machine to just try crazy ideas out on like that, I have a couple I could use but finding the time is the real issue. More power to ya if you have the time and patience. I will say to keep safety in mind and use sound engineering or wear good protective gear, both would be good.:thumbsup:
 
#5
One of the main reasons I thought about using a lawn tractor transmission was that the particular one I have available has a horizontal side input shaft, instead of the regular vertical shaft on top.

Here's a diagram of it here. Look for part #39, it's the horizontal input shaft. The only problem is that it's located on the right side rather than the left, so trying to figure out how to mount it might be a problem. Hmmm.
 
#6
I built this three wheel tote gote using a three speed lawn tractor transaxle with reverse. The shaft was on the right side of the trans axle but the gears in the trans reversed the rotation, so the motor needed to be put in 'backwards'. I used a regular tote gote clutch and primary jackshaft. The jackshaft brake allows me to stop the jackshaft from spinning to put it in gear or reverse direction. The trans axle brake is hooked to the 'foot' pedals. It was a fun project but took a lot of head scratching.
 
#7
Hey, that looks cool! Neat idea! Were there any problems with the engine running/facing backwards?

Which direction did the shaft have to turn to make it go forward in those 3 speeds?

(I'm imagining myself assembling something and then realizing it goes forward in 1 speed, and having 3 speeds in reverse :laugh:).
 
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