Motrcycle engine

[pezgoon]

well I actually have two questions here, one, me and a friend are trying to modify his old go kart and we wanna stick a motorcycle/dirt bike engine in there, but his is a single seater, I keep trying to tell him, that we have to get a two seater frame because the single is too light and doesn't have the width, he says that all we have to do is add some more room in his engine area (I'm a welder) and it'll work, whats your guy's opinions?

second question is does anyone know where to find a motorcycle engine, we're looking for one in the area of $500-800 or so, and i think we should stick around 500-750cc's he wants something like 1200, any suggestions? and ebay is useless cause the closest ones on there are 6 hours away (im in New Hampshire) and it would be nice if craigslist still had an engine section, but they dont, any suggestions other than to look on clist? and also if anyone would know of a place to get a two seater frame, it doesnt have to even be a rolling frame, just the frame. We would rather not spend the 3 months or so building the frame, but if we must we will I guess lol

P.S I can post pics of his cart if that would help with the first question
thanks

 

[crazycart]

Post up the pics of the frame, it will help a lot. I dont think a 1 seater is too light, but you should definitely widen it. For 500-800 bucks you can get yourself a pretty good engine. I would look for a complete/crashed bike. It will make it much easier. And for the size of the engine, it all depends on how old it is. A early 80's Yamaha 1000 will make 100hp where as a new CBR600 will make 120+. Personally i would look for one 600cc+ Good luck

 

[Kenny_McCormic]

I would do a complete scratch build if your going over 1 cylinder.

 

[STreetKArt]

im tring to do the same thing and i cant find any thing no jet ski engines or motor cycle engines and i was even looking for a out board boat engine!!!!lol
idk iff they would work

 

[pezgoon]

Heres the pic of the rear end



24 wide and 21 inches to the seat

 

[modelengineer]

You can put a bike engine in there, just make sure that you add air scoops and vents, possibly a fan too for when you are stationary.

I recommend NOTHING more than a 400cc, an even that would be dangerous. That rear swingarm is designed for ~6.5hp?, maybe 10hp for some safety factor, and you want to put in over 50hp? 100hp?
It's not a question of IF it will break, it's how many seconds you get before it does.

Like Kenny says, build one from scratch so that you know it can handle the power,

 

[pezgoon]

we are going to rebuild the whole rear end from the seat back

 

[modelengineer]

Would be cheaper and better to sell it and build from scratch

 

[SpyGuy]

Definitely consider wheelie bars and even a rollcage. I watched a guy with a Kawasaki 750-powered gokart dump the clutch and launch the front end almost straight up - bent the hell out of the wheelie bars, which were about the only things that saved his life besides the seatbelt.

 

[BradenM]

I agree with modelengineer, if your going to play with big boy motors, make something that can handle it. If your looking to upgrade for more speed + accel, maybe go for a 13hp clone, and keep it stock. Even that, would be sketchy.

 

[pezgoon]

ya we are looking for more acc and speed, but we also want a manual tranny in it not cvt or centri

 

[pezgoon]

and where is your suggestion to get a clone that size from?

and we want something closer to like 20hp

 

[robin]

use a 125 bike engine ime using a cg125 i would stay away from 2 stroke on an of road cart tho

 

[pezgoon]

Why do you suggest to stay away from 2smokers?

 

[Kenny_McCormic]

He doesnt understand them.

 

[modelengineer]

If you are doing really slow offroad trail riding, then a 4-stroke would be better. Otherwise, for the engine size, the 2-stroke will almost always be more powerful (and therefore better)

 

[robin]

He doesnt understand them.

what?? i tuned the **** out of my rx did all the porting engine rebild my self etc 20hp from 80cc is not easy you no

i sugested not using a 2 stroke becus thay re usaly les reliabull some you have to mix the petrol and thay dont make much torq withs is what you need in an of road gokart

its like a cbr600 v xr650 the cbr has more power but its all in the high revs the xr will pull from from low revs and provide more traction thats why the ducattis are good on the track the v twin provides more gripp out of the bends than the revy 4pots

 

[BradenM]

2 strokes make plenty of torque for an off road application. Honda thought so! For Bang fo yo buck, you cannot beat a 2 stroke. And the simplicity is a distinct advantage for farm applications.

The only time I would suggest a 4 stroke, or have suggested one, is when the user is less likely to want to have to mix oil and petrol for each tank, or mix up huge jerry's, and if a farm is already running a half a dozen 4 stroke motorbikes/quaddies, it's much easier for that person to simply add gas to the tank and go. It's not that hard putting oil in gas, but it doesn't take much to weld your piston to your bore. I would argue that 4 strokes are slightly more user friendly, by a factor of .1.