Engine Swap?

[Sarg.]

SO, Me and a friend are planing on building a couple of bombed 250's back up into decent machines....BUT, Niether of us, want to keep the two stokes....any SUggestions on engines....400ex, 450r, and the where about I can located these, and the $$ would also be helpful.....thanks alot....

[250R-Dee]

You really need to ask this question in the Hybrid Forum since most of us frown upon destroying a perfectly good 250R frame just so a person can be a part of the "in crowd".

Anyway, a 450R will not fit because the motor is too tall and the 400EX motor will be a downgrade. The YZ426 will fit better than the honda motors. If you are going to build a hybrid from scratch your best bet is to get a frame with 250R geomery that accepts 4poke motors.

Parts can be found on classifieds forum and Ebay.

Good luck and don't forget to check the HYBRID FORUM.

[DPR250R]

Originally posted by 250R-Dee
You really need to ask this question in the Hybrid Forum since most of us frown upon destroying a perfectly good 250R frame just so a person can be a part of the "in crowd".

Anyway, a 450R will not fit because the motor is too tall and the 400EX motor will be a downgrade. The YZ426 will fit better than the honda motors. If you are going to build a hybrid from scratch your best bet is to get a frame with 250R geomery that accepts 4poke motors.

Parts can be found on classifieds forum and Ebay.

Good luck and don't forget to check the HYBRID FORUM.

Could not have said it any better myself....

One local guy runs a YZF motor in a 250R frame... to me it looks like he did a real nice install. The frame seems to crack a lot though...

[deathman53]

get a frame designed for that motor, 250r frames can't handle the torque that a new 4 stroke motor puts out. Don't hack a perfectly good 250r frame, Lsr still sells 250r frames that use newer 4 stroke motors. I personally think its kinda sad that 20 years later people still want a 250r stye frame, Honda hit the nail on the head 20 years ago and nobody has caught-up yet(except the guys who make/made aftermarket 250r frames). The 85/86 atc250r was another perfectly designed frame and the trx250r frame was a copy of that with a different front end. If you ask most of the pro's off-the-record, they will tell you they miss their 250r's and/or 250r frame hybrids.

i dont get why you wouldnt want the 250r motor...get a 310 or 330 motor and youll have more of a thrill on those then any 450 IMO....but i do see alott of people used the 426 motors....but dont hack up a decent 250r frame, if you want a 4 stroke motor in there then buy a frame that accepts the motor better...the R frame was built for the R motor...plus there are getting to be less and less R frames out there, dont destroy another one for some 4 stroke...either buy a 450, or build up a 250R...not a CRF hybrid

[deathman53]

the 310pv(really 295) I have on mine puts out enough power to rip your arms off. A well done 330 will really rip. I'd bet its faster than most 450's.

[Sarg.]

Well Guys, thanks for you unbiased opioin, haha, jk....but I think Im guna build a 250 and keep the original 250 engine, and my buddy, hes moved on to bigger but not necesarily better things....thanks alot....