Home-made 250CC 2-stroke shifter project

[SL100OKI]

I want to build a go-kart using a 8 Honda CR250R dirt bike motor + tranny. WIth it the radiator and it's FMF Fatty pipe. I went and found the only 120V american power, wire feed flux core welder on this little island. Now the questions flow into mind:

1. but the first 2 is how would i build the frame to suit the motor size, a radiator, chain drive, and the 2-stroke FMF fatty exhaust pipe. Oh, also the air box + carb. That will be my first issue, fitting all that on some sort of semi light steel frame and my 200 lb, 5 11 hind end.

2. Should I use the existing clutch system that is in the tranny and build some sort of clutch petal or clutch handle? I'm trying to keep it as cheap as possible, while still being limited to a welder and normal power tools for cutting (no oxy-acetylene, band saws, or plasma cutters) I'm a low income Sergeant is getting fed up with golfing with the neighbors.

3. Can I make my own axle or is it cheaper and lighter to use a prefabbed. Keep in mind that I have to ship everything to an FPO-AP address which gets me stuck with some suppliers.

I noticed Northern Tools had the 1" axle with 1/4" keyway. Shipping cost unkown, their website said "I" must call due to "FPO-AP". Well that ain't cheap from Japan, guess I need to go ahead and order Vonage.

And i've found H.D. 1" axle sprocket hubs and H.D. sprockets to fit my #520 chain.

Thanks
S.C.

 

[jrjulien1]

sounds like a pretty cool project im doing one similar to that with a motorcycle engine and trans but i dont have one yet

keep us posted on your progress

 

[imported_robertdjung]

Here's some first thoughts:

Dirt, or pavement? If dirt, get a solid axle. If pavement, you'll either want a differential or you want to only power one wheel.

Frame: I imagine it's going to just have to be a very custom job. The basics of frames are all outlined here. I'd take that and see how your mounting system will need to be tweaked. Or post some pics and we'll brainstorm.

Clutch: personally i'd keep it as close to what it already is as possible, since that means less fabrication and you'll be tearing aroudn sooner... Maybe a rod that comes off the shifter, and then mount the clutch hand lever on the shifter rod, like a suicide shift on a motorcycle.

For parts: I don't know what that chain size is, but I think BMI has a lot of motorcycle related parts. Might be an issue getting sprockets and hubs and axles to all mount, I'm unsure.

 

[Steven]

Wait a second... a CR250... that's allot of power for one wheel drive don't you think? You'd need to use that diff, otherwise you'll find that the wheel driven by the engine would wear out like a shoe rubbed on the road on a motorway... Good choice for an engine though, that much power would surely catch the girls

 

[jrjulien1]

ya hes right that one tire would be constantly spinning out and would make the kart harder to drive and wear out the tire

 

[Kawabuggy]

I'm not sure of the differential that you are speaking of, but the ones that are made specifically for go-carts can only handle up to 8HP. I believe that the Honda motor is going to produce more than that...

 

[jrjulien1]

iv never heard of a power restriction on diffs before but i suppose it would break at some point anyways a solid axle is cheeper and would perform just as well offroad but would suffer a little on DRY pavement on wet or slippery pavement it would feel like its offroad

hope this helps