Assuming I can find one (i'm working on it), what considerations need to be made? I'm sure it's not as simple as pulling out my 250R motor and putting in the KTM motor. Because the motor was designed to pull the weight of of bike and not a quad, wouldn't the engine need to blueprinted and modified to have the powerband altered? I'm assuming, as is, it would end up w/ a really late hit...later than on the bike because of the weight difference. What about a counterbalancer for vibration? would that be needed? a smaller carb for lowend?

I know the Tecate 4 used an '87 KX250 motor w/ head and porting mods to "make it suitable for ATV use". This is why I ask these questions.

Am I on the right track? or is this idea even harder than I'm realizing? any help is appreciated!

 

You should be able to change the gearing for the motor to pull it. Motor mods would probably help too.

 

Change gearing? You mean the sprockets or the actual gears in the tranny? How exactly would you do that if it's tranny work?

 

the sprockets. Why do you want to trade the 250r motor for the ktm?

 

KTM has come a long way. Their 125 motor is being praised as the best 125 motor EVER. It has it all. And the 250 is a superb motor as well. They have a 360 or 380cc 2 stroke motor as well that supposedly really rips. I'd love to get my hands on one of them even more!

I've always liked KTM and since I don't really ride my R that much, I had the idea of making one a while back. And after seeing the 520 KTM quad, I got KTM fever again. And since I prefer 2 strokes I thought it would be cool to have a 2 stroke KTM....one of kind! All decked out in orange! If KTM already made quads, I'd probably already have one! And I figure: If and when they make a quad it'll be a four stroke and be quite pricey. So I'll spend less this way and like it better.

Why? you don't think it's worth the trouble?? why if not?

 

why are u even willing to do this the trx250r engine might be the greatest 2 stroke engine ever made..i mean come on there's not gonna be a huge diff other than the ktm engine other than the trx250r has an almost perfect tranny and it has honda wrote on it.it might be a bit more high tech but not worth all the hassle...by the way ktm did make back's like 3 years ago

 

The first thing I would be concerned about is are you using this ATV for racing. If so, AMA is talking about ruling out motorcycle engines in atv frames. I was told that this would be in the rule book for this year, but now it is said to be in next year's. It seems the high tech/high priced YZ426 yamaha and the crf450 are smoking the common racers 400ex's. Rumor has it that those bikes will be forced to run in an open class.
Just something to keep in mind.

 

tell me something, alkiburnin. Do 400EX's race in the pro class (250) where you are? If they do, do they have any success? I ask this because I get tired of EX riders talk about their quads like it's honda 4 stroke answer for the R. I think it's load of crap but they believe it w/ all their hearts (or "hopes" I think).