hybred in a 250r chassis help

[woodsracer144]

ok so first off... i know someone is gonna say "USE THE SEARCH" well i have and i dont have time to swift through loads of posts...
2nd what do you have to do to a 250r chassis to get a yzf or crf in it... i would like to mount the rear motor mount out of the pivot bolt so wouldnt have to chop up my swinger... the rear mounts the only hard spot for me... i can get the rest of it all done... i've done a yzf 400ex before and the swinger was the hard part for me to have it shimmed right along with the oil tank... but any ways... thanks for the help

[yfzttracer76]

Dont be suprised if people tell you not to chop-up a perfectly good 250r frame that isnt even in production anymore. When it would be easier to buy a used hybrid frame that probably takes the same componets.

[deathman53]

I have a stock 250r frame and lsr 250r frame w/crf motor. The 2 frames are so different, swingarm bolt heights, upper frame rail height and then the swingarm. I seen 2 styles of 350x motors in 250r frame, cut the stock motor mounts and weld in new ones or cut out the bottom frame rail and lower it down so the sprocket is level with the swingarm. The first way resulted in lots of thrown chains and funny swingarm guide wear. The second way resulted in some guide wear, very rare thrown chains and correct suspension action.

Yes, you can do the crf450r in a stock frame, but w/o modifying it alot, so the chain lines up right and is level with the pivot bolt, it will result in bad things. I can't forget about how the gas tank will have problems fittings, as the crf motor is taller.

[woodsracer144]

no i wouldnt do this to a good oem frame... this is my prp that i'm tired of looking at sitting around and i would like to get a cyl and poiston for it but im a cheap ******* so i dont know... i just like the 400f i had... and i would like that in a 250r geo and not a 400ex geo.... i have a 85 atc motor but i need a clutch and a top end... i have 2 heads one oem and one cool dome and i have a lrd cylinder for a 250r that needs a sleeve... so i thought i would just put a hybird out of it now... i can rig up front mounts really easy its just the rear i would need help with... so im not really sure what i should do now... i thought about using a cr250 motor or something like that but theres not CB in it so it would kill me...

any thoughts on this...

[racerx573]

It would be cheaper to fix one of the 250R motors.


If you want a conversion that's done right and will last more than 5 races, you're gonna need some serious/professional machine work.

Is your frame a stock link, no-link, or CR500 link?

I did this on a Laeger's 250R CR500 link frame, and we did a lot for it to work properly and align right.

We machined the ''89 style CR500 link swingarm to go around the motor, made custom motor bushings to fit the 250R pivot bolt through the motor (used '89 bearings).

The pivot bolt was relocated and moved up about 1/2" We relocated the shock/linkage mounts up 1/2" as well to compensate for the geometry changes.

Cut the bottom "V" rails out and put a cross bar and new lower mounts, so the motor was not too hight or too low in the frame.

Made a cross bar headstay using YZ450 headstay mounts.

Used a Walsh kicker ext.

The motor was offset about 3mm so we used a standard 3mm washer in between the sprocket hub/sprocket to prevent chain derailing.


Also do you plan on using a wet or dry sump motor?

We went with the wet sump kit to prevent having to make a bracket/room for an oil tank...



Lots of work involved plus the cost of the motor.



Just fix your 250R stuff, or buy an aftermarket frame for a hybrid.

[GOTFEAR]

Originally posted by woodsracer144
ok so first off... i know someone is gonna say "USE THE SEARCH" well i have and i dont have time to swift through loads of posts...
2nd what do you have to do to a 250r chassis to get a yzf or crf in it... i would like to mount the rear motor mount out of the pivot bolt so wouldnt have to chop up my swinger... the rear mounts the only hard spot for me... i can get the rest of it all done... i've done a yzf 400ex before and the swinger was the hard part for me to have it shimmed right along with the oil tank... but any ways... thanks for the help check it out

[woodsracer144]

i saw your build... i didnt want to have to chop the swinger though...

[audioworks04]

You will chop up the frame, but not the swinger? Im confussed. Whats so bad about 400ex geo? By the time you have all the time invested in this that you will have inorder to do it right you could have bought a used hybrid frame and been riding it for a while, probably with cash in your pocket to spare and way less headaches and lost hair.

[woodsracer144]

i dont know what the hell im going to do... i just want to ride my quad thats all i know... im trying to sell some extra parts i have to get it going....