motorcycle motor gears??

[pupuslinger]

i have a xr50 motor i am planning on putting in my stool. the gear on it is not 35 chain. and i know that all the kart rears are 35 as far as i know. what are people doing? are they changing the pinion or the rear sprocket to run a certain chain?

[moto1fast]

Hello, Your XR50 is running either a 420 or 428 chain and sprockets. You will need to modify a rear sprocket that is 420/428 which ever you have to fit a kart hub or build a hub to fit your axle and your sprocket to bolt to it. I would build a hub so I could change from different size sprockets (number of teeth)without having to modify each sprocket! You can do this by using a regular kart hub that fits your axle and build an adapter that would bolt on the hub and have other holes drilled in it to fit your XR50 sprockets! Another way would be to have a plate welded onto the hub with the bolt pattern of your XR50 sprocket drilled and tapped in the plate! There is a lot of ways to do this mod! Hope this helps and Good Luck!

[pupuslinger]

i wanted to just make a new hub but i dont have access to a lathe anymore. i was hopeing that there was just a bolt on adapter type deal that i could get. i guess i have to get a hold of a hub and see how close it is. i was hoping to adapt the front gear so i could use the split kart gears in back, but i am sure that would be much harder to do.

[pupuslinger]

k, i have the hub that i had made, and have a xr50cc with a 88cc big bore. i finally got to take it out for a spin, and it is not bad, but first gear is absolutely useless. i have a stock sikk bike gear in the back, it is maybe a 40 or so. i have not had any luck trying to find something in the 30 tooth range, the smallest i can find is 34. any ideas, or do you think that 30 would be to low, i put a 17 in front, and i could always go smaller if the one in back was to small, i think it goes 1 tooth in front equals for teeth in back, at least that is how big bikes were. i would rather get small in back and then i can adjust the front, they are easy to come buy and i have them readily avaliable.

[moto1fast]

Are you trying to get more or less top end speed? The bigger the back sprocket the more torque you get but less top end speed and vise versa on the front! You are right about # of teethe of the effect on the front sprocket versas the rear sprocket change! 1 tooth change on the front is the same as 4 tooth change on the rear!

[pupuslinger]

i am looking for more top speed. with the three gears, i should be able to go pretty small in the back, but i cant find anything that small, 30 or so. i can just leave it in 3rd now and drive around, which is cool. but if i can make if fater, i might as well:me: , first gear is just pointless, only good for about a couple of miles an hour, and torque it has got plenty, almost rolled myself right of the back the first time i blipped the throttle. second is not bad, it goes ok, but still low, so i think i could pull a 30.

[moto1fast]

You will probably just have to modify a sprocket to fit a 30 tooth is pretty small for the back. You can get a 30 tooth sprocket # 40 that will interchange with a 420 chain or pitch. You can find them at a tractor supply and then drill out your bolt pattern using your rear sprocket as a Guide! Hope that helps!

[Mike Bean]

Hey Pupus,

We have a setup for 1" or 1-1/4" axles that allows you to run a 420/428 chain with a 28 tooth sprocket. I used one for a 428 chain on my 125cc build.

I am pretty sure we can also get other chain sizes if you need.

PM me if you need one...

Mike Bean