I recently bought a 400ex with a cracked case. I want put etiher a honda 250 or 500 2 stroke motor in it, or 450 4 stroke. my question is will the 500 be to much for the suspension to handle? will they even fit? I can make motor mounts and the simple stuff but I aint ever undertook something like this.

 

i have seen a cr500 engine in a 400ex cr 500 have about 50hp so will just be like a 660 raptor engine but with more rpms
a big single cylinder two stroke would be excellent on the dunes

 

well it will be rode in the dunes, but the bike already has american racer flat track tires on it and I was kickin the idea around about doing the local TT series. it runs in the summer and the XC seies runs from Oct. thru Feb. I was thinkin that the 450 would probably be a better motor but the two stroke has the punch to it. also who makes that 250r style plastic for the 400ex?

 

tell me your email and i will send u a picture of one

 

send one to me also!! i wanna see the cr500 in the 400ex frame b/c im doing it soon!

 

250 atv motor is a good fit, 450 bike motor is the best choice. 500 2 stroke doesn't make the translation to atvs well.

 

i agree in that a 450r motor would be ideal for that bike. the 400's suspension really sucks as it is and before putting a motor in it i would invest in a set of shocks for that thing. You can convert 250r plastics to fit the 400 and you can also convert the 450r plastics to fit it too (if you have an older 400). A 500 in that bike would suck due to vibration

 

I was going to buy a set of PEP shocks for the front that came off of an 88 250r, and my friends dad was going t lengthen out the stock A arms. He owns a machine shop and has been a union welder for like 20 years. He did this to an 89 warior and I was surprized after they were powdercoated they looked like any aftermarket long travel A arms.

 

hey 1988fast250x send me your email than i will send u the picture

 

service honda sells new 250r, using 2001 cr 250 motors and puting them in 400ex chassis. and by the way cr 250 almost makes 50 hp a 500 is just over 60hp but only so low cause they stopped development in like 1990