side project: mini 3 wheeler

[BombBoy94]

so i know this has nothing to do with karts, but i found one of those mini motorcycles in the garbage a couple weeks ago. got it running, fixed it up and mad it look nice. well i just happened to have two offroad 4wheeler tires the same size as the mini bikes, and i want to put them on the bike itself. i need some help. im thinking fabricating a solid axle that fits in on the fork, transfer the sprocket, either weld it or make a mount for it on the axle. but the issue is the acceleration of the bike, it sucks. any way i can change it without changing the entire motor? its a 49cc air cooled 2 stroke. any other ideas on the setup would be grateful. pictures will be up soon.

 

[DS13]

so i know this has nothing to do with karts, but i found one of those mini motorcycles in the garbage a couple weeks ago. got it running, fixed it up and mad it look nice. well i just happened to have two offroad 4wheeler tires the same size as the mini bikes, and i want to put them on the bike itself. i need some help. im thinking fabricating a solid axle that fits in on the fork, transfer the sprocket, either weld it or make a mount for it on the axle. but the issue is the acceleration of the bike, it sucks. any way i can change it without changing the entire motor? its a 49cc air cooled 2 stroke. any other ideas on the setup would be grateful. pictures will be up soon.

That solid axle may work and if ya do that make a sprocket mount DO NOT weld the sprocket or the mount on. To change the acceleration you have to change the gear ratio...

 

[BombBoy94]

That solid axle may work and if ya do that make a sprocket mount DO NOT weld the sprocket or the mount on. To change the acceleration you have to change the gear ratio...

awesome, thanks. and how would i change the gear ratio? a kit or manual orr...?

 

[DS13]

any ideas on how to put the sprocket on then? and how would i change the gear ratio? a kit or manual orr...?

Your axle would have to have a keyway in it which has a key in it and the sprocket mount has a keyway in it too. then the mount should have screws where you can take off your sprocket on and screw on another.

 

[BombBoy94]

Your axle would have to have a keyway in it which has a key in it and the sprocket mount has a keyway in it too. then the mount should have screws where you can your sprocket on and screw on another.

my apologies, misread your post. thanks, appreciate it.

 

[OzFab]

and how would i change the gear ratio? a kit or manual orr...?

By using a larger axle sprocket or, if ground clearance is an issue, you may have to resort to a jackshaft. Be aware that this will lower your top speed (good acceleration or good top speed, pick one).

At the end of the day, a 49cc engine doesn't produce a lot of horsepower so, getting decent acceleration will always be an issue

 

[BombBoy94]

By using a larger axle sprocket or, if ground clearance is an issue, you may have to resort to a jackshaft. Be aware that this will lower your top speed (good acceleration or good top speed, pick one).

At the end of the day, a 49cc engine doesn't produce a lot of horsepower so, getting decent acceleration will always be an issue

replacing the sprocket was the conclusion i came to as well. and jackshaft would be a good plan B, thanks. and im not really needing speed for this, just acceleration. another question, steel or aluminum axle, it needs to be durable, offroad worthy yah know. haha.

 

[DS13]

steel or aluminum axle, it needs to be durable, offroad worthy yah know. haha.

Steel, more bang for your buck

 

[OzFab]

Steel, more bang for your buck

Steel might be 4 times the weight of ali but it's also 4 times stronger... & 1/4 of the price...

 

[Fallenleopard]

This sounds like a good idea mate. Have you got any photos of the bike and parts you are using?

 

[BombBoy94]

Steel, more bang for your buck

thats my issue as well. very heavy. im looking through a couple junkyards to find a suitable lawnmower axle, if i can. if not, fabricate one. and ill have pictures up tomorrow. to dark for pics now.

 

[OzFab]

If you can get your hands on a complete ATV rear axle of comparable size, you're almost there

 

[DS13]

thats my issue as well. very heavy. im looking through a couple junkyards to find a suitable lawnmower axle, if i can. if not, fabricate one. and ill have pictures up tomorrow. to dark for pics now.

Steel isn't that expensive, well at least where I live, I got a 3 and 1/2 foot piece of 1" cold rolled round for like $9.

EDIT: i mean you could find stronger alum because they do make different kinds but you are gonna pay a very pretty penny for it.

 

[Fallenleopard]

If you can get your hands on a complete ATV rear axle of comparable size, you're almost there

I had an idea similar to your 3 wheeler that is close to what fabroman is talking about. I was going to find a motor frame and attach a quad axle I already have to the rear. I was going to make a modified swing arm to fit the axle so maybe you could do a similar thing?
Find a axle then just modify the swing arm to suit

Just an idea.

 

[BombBoy94]

Side Project: Mini 3-Wheeler (pics)

like i said before, thinken solid axle from a lawnmower, or fabricating one. weve also got an old kart motor, i think 100cc, gonna put that on here.

 

[raposak]

i love it. looks like fun

 

[BombBoy94]

i love it. looks like fun

thanks man, it will be if all goes well.

 

[landuse]

That dinky little front wheel lokks weird with the big boys on the back