KDXRIDER.NET

ok im kinda new here so i thought ide ask you guys about a an aluminum framed kx125, kdx200, or kdx220. im coming off a 112 which i might trade for a kx250f , just one problem never did like the four strokes so i was talkin to my dad if we could do a hybrid he said yea, but i had to pick the motor . my first suggestions were the kx125 motor, kdx200 motor, kdx220 motor, kx250 motor, and the kx500 motor . well i already have a kx250 so i didn't want to use it because i absolutely love it and it would be a shame to take it down . the kx500 i decided was too much power so that was out . then so my last three were the kx125, kdx200, and kdx220 motor and i can't decide between the 3 . what do you guys think? can this be done? if it can what all do i have to fab up, already got the hookups. do u think this could be a potent mix for an mx bike.

What are you going to use it for.... and what frame are you going to use?

It depends on how and where you plan to ride it. In my opinion though putting a KX125 engine in it would be stupid. You would be better off just finding a KX125.

If you do the hybrid, I would say go for the KDX200 motor.

just so you know, the KX250F motors can have problems with the cam systems that lead you into buying a new head and nearly all parts that go in it. Not real cheap when it happens. Of course, the reliability of 250 4t MX motors in general is why you can find so many of them without running motors.

What do you need to do to build the hybrid? Simply read all those stickies above, and most of the other posts.

It sounds like you're doing mainly MX. Here's my suggestion.

Take your KX250 motor and put it into the 250f's frame (KX250AF).

Then, buy a KDX200 motor and swap it into the KX250 frame.

This way, you'd have an awesome MX machine and an awesome mellower MX machine that would be easy to make into an off-road bike.

Why have one hybrid when you can have two?

a kdx engine in a 250 frame, the gains aren't really worth it...

I'd say your best bet for a potent MX bike would be the KX250 motor in a carefully rebuilt KX250 frame. I doubt the KX250F frame is that much better than the KX250 frame. Why bother?

For a woods bike either KDX motor would be great in your choice of KX(F) frames. You'd have to set up the suspension for woods use, of course.

If you want to do something just for fun than I say mix and match any way you want. The 125 motors are always fun. If you are coming off of a 112(?) and don't need it any more than put a KDX or KX125 motor in it and leave the KX250 alone.

im using a 2007 kx250f frame. i don't wanna use the kx250 motor because its my dads and he needs a bike too. i just wanna do a hybrid for mx not trails. also because i don't wanna switch to 4 strokes. i think the kx125 engine in a kx250f frame would be ggood because the 250f has a lighter frame the the kx and the power to weight ratio makes it more powerful than a stock 125. i just wanna know if you can make the 200 and 220 motor work for the mx track. also, what all i would have to fab up?

It's not geared for the track... It's geared for the woods.

That in itself is enough to disqualify it.

The YZ125 '05 and newer is a better bike anyway. Lighter than the KX and better motor and suspension. Built better too. You might want to give one a try. I don't see you gaining anything by making a hybrid if it's a track bike. The manufacturers already make those, and they're very good at it.

The reason people make hybrid KDX'x is to get a lighter bike with more modern suspension, while keeping the woods-friendly motor and transmission.

Re: 'i just wanna know if you can make the 200 and 220 motor work for the mx track.'

You bet!


...as a pit bike.

I can't imagine a KDX motor 'working' on a track no matter what frame it's in. What is it you figure there is to be gained from fussing with putting a KDX motor into anything 'for the mx track'?

Sounds like the ruination of a prefectly good KDX motor to me.

Why not a KX250?

so do u think i should go with a kx125af and just bore or stroke it if i need more power?

so do u think i should go with a kx125af and just bore or stroke it if i need more power?

Seems like it.

couldn't you just change the sprockets to gear a kdx for the track?

no... final drive ratio and gear ratio are 2 different things. A KDX is a wide ratio gear box and MX bikes have a close ratio gear box.

can u do anything to change that?

No.... not without spending more than the bike would be worth.

I'd forget about the KDX motor if I were you.

alright if i do go with the hybrid ill use the kx250f frame with a kx125 motor and just bore it if i need more power. now what all would i have to fab up to make this work and has this ever been attempted?

not on this site that i can remember, you're on uncharted territory

does anyone know anybody i can talk to if i do decide to attempt this

have you tried thumper talk, 2 stroke section?