GSX250 go kart project

[yamahaggis88]

Not really sure if this is in the right bit, but oh well, mates thinking about putting a GSX-250 motor on his go-kart, just unsure where to start but we wanna do the whole thing ourselves Hasn't picked the motor up yet but is bidding on one at the mo. It's got a 125 2 stroke single on it at the mo which is getting a bit tired, its an ex race kart so has had a hard time. Main questions basically involve the exhaust, which is a major, sprockets/chain, cooling, and making up a shift linkage.

First up, I dont know much about these engines and im trying to find out if theyre liquid or air cooled, and ive had mixed answers with some sites saying air, and some saying liquid, looks to be a fairly early model engine and doesnt come with a rad, and its covered in fins so im presuming air cooled? If not, and its a liquid cooled engine, we want to mount the radiator vertically, beside the seat, and use an overflow tank as a pressurised high point rather than the radiators standard cap. Will this work? If not, how should we be going about this? If its aircooled, should we be worried about overheating at low speeds?

With regards to chain and sprockets, how much do we have to play with, as i presume we're limited to GSX factory sprockets. I'm only asking as we dont have a hell of a lot of ground clearance with the factory rear sprocket and will probably have to play around a bit as i have a feeling the gearing will be too tall to be useable on a go-kart. Also, can a chain be shortened up that much without dramas? I'd imagine we'd be taking most of the links out, think the chain length at the moment, from first to last link, is about 400mm using a sliding axle as a tensioner.

Exhaust wise, obviously it will have to be kept at the same length for the engine to run right, right? Can we bend up new pipes after the first join of the headers to keep the effective length the same but in a more confined space? Not really keen to get into re-jetting and balancing carbs, we're trying to keep this as simple as possible. Will there be any adverse effects of having bends in the system? We will be using mandrel bends and mild steel piping of the same diameter.

Finally, shift linkage, we will be mounting a factory clutch lever on our gear lever, which we are mounting beside the seat, which will be mounted on a bushed pivot. How would we work out how long to make our linkage, and also how do we work out how far below the pivot point should the clevis linkage be? Obviously you want an easy shift but dont want to be moving the lever too far or putting any excess strain/effort on the gearbox. We will be joining the rod link up to the factory shift lever in a way that you have forwards for down, backwards for up. Would this work?


Not really sure if this is really the forum to be asking, but have had good answers from you lot in the past Any help at all would be greatly appreciated, and any more advice you guys can offer as well, and please, no trolling, the whole projects just a bit of fun

[Spearfish]

search for vids on you tube, they could answer you questions



or bigger....

[Kickaha]

With regards to chain and sprockets, how much do we have to play with, as i presume we're limited to GSX factory sprockets. I'm only asking as we dont have a hell of a lot of ground clearance with the factory rear sprocket and will probably have to play around a bit as i have a feeling the gearing will be too tall to be useable on a go-kart.

You'll be running little 5 inch kart tyres so gear which will make the overall gearing heaps lower anyway, you can get sprockets made to suit the rear and run stock sprockets on the front

Also, can a chain be shortened up that much without dramas? I'd imagine we'd be taking most of the links out, think the chain length at the moment, from first to last link, is about 400mm using a sliding axle as a tensioner.

Short chain decreases the life but not that bad that it will cause any problems, all karts run short chains

Finally, shift linkage, we will be mounting a factory clutch lever on our gear lever, which we are mounting beside the seat, which will be mounted on a bushed pivot. How would we work out how long to make our linkage, and also how do we work out how far below the pivot point should the clevis linkage be?

Don't waste your time, have a look at some other Karts with paddle shifters under the steering wheel and make one of those using a morse cable

[yamahaggis88]

Any links to for the paddle shift? We're on a budget, remember, one poor apprentice, one poor trucky with too many toys

[pete376403]

Stick a gsxr1000 motor in it. With those tiny wheels it could run in top gear and you wouldn't need a gearchange
http://www.youtube.com/watch?v=0xbZt9-xtuU

[yamahaggis88]

All comes down to price again, one of my workmates has a 636 motor in his shed, but it needs parts, also I'd say the little 250 twin would be a better fit on such a tiny frame, as well as the fact its more of a fun driveway/park hack than something we intend to go ridiculously fast on...