Need help choosing an engine

[cd2781]

Ok guys, i plan on building my kart from the ground up since my yerf dog kart probly wont hold up to what i want to do.
The question is, what do you guys recommend. I want something pretty quick as this will be a asphalt/yard kart. Ive thought about using a 250cc dirtbike engine since it has the transmission.

If i do the dirtbike engine, would you guys go 2 stroke or 4 stroke?

Also, i kinda want to build up a clone. I enjoy tinkering alot and this would be interesting. It would be a fully built clone probably as i can do all the work myself minus any kind of machine shop work. I know itll cost a little bit to do it, but i still think it would be interesting.
Lmk what you guys think. I do know that the dirtbike engine will have more power stock, plus the gears.

 

[firemanjim]

A 125cc engine, 2 or 4 stroke, is more than sufficient for what describe as what you want..... I see 125cc powered karts hitting 80-90mph..... How fast do YOU want to go?

 

[cd2781]

That would be maximum lol. So would you do a 125 dirtbike engine? Or just build a clone. Either way, im probly gonna pep the motor up some

 

[firemanjim]

I put a 125 in a kart I built from scratch. And I'm using a 200cc engine to power my build off kart...... So I can't say I wouldn't......

 

[cd2781]

Are there the same type of performance mods available for the dirtbike engines as they do for the honda clone engines?

 

[cd2781]

And would you go 2 stroke or four stroke? Possibly going crf 125

 

[OzFab]

That depends on exactly what you want it to do; a simple guideline is:

-a 2 strokes powerband is somewhere around 6k-10krpm; great for top speed but, not great for hill climbing
-a 4 strokes powerband is somewhere around 2k-5krpm; you still get a decent top speed but, you also have the ability to climb a hill from a standing start...

 

[cd2781]

Ok that makes sense. In that case, i think im just gonna go with a clone thatll be hopped up a little and change gearing to fit what i want. I think id be happier with that.
I dont want anything crazy because im not racing or trying to build some totally crazy kart. Maybe i can enter mine in next years contest

Ill actually be building two karts. My fiance is wanting to learn everything from how to weld to motors and she thinks this project would be awesome, so im gonna help her build her own.