My wr 250 motor/ YFZ 450 frame hybrid

[Junior Boom]

This project started when i was becoming to big for my blaster that i was racing and still had one more year to race in that particular class. My dad decided that the the best way to overcome this problem would be to build a hybrid. The project started of with a brand new Yamaha wr 250 and a brand new Yamaha YFZ 450. It took my dad six weeks of intensive work to build the bike. After half a seasons racing i am very impressed with the bike and it is working well for me.

[Junior Boom]

some more pics

[Junior Boom]

in action

[NickG5755]

the 250 yamaha should have built.

[UNBROKEN]

thats one hell of a quad why did ya go with a wr motor if ya ride track ? and wut does it top out at with that motor

[NickG5755]

the only difference between the WR motor and the YZF is the gearing , the WR is obviously higher geared. But not by a whole lot.

That is considering you did the Grey Wire mod (changes the ignition to the YZF style)

[Junior Boom]

I race enduros those are just a few jumps at the start of one of our races. Chose the wr motor for the longer gearing for enduro. We done the grey wire mod which made a big difference. It seems that the gearbox is not quite strong enough for the quad as after only 30 hours the dogs on the fith gear have worn round. We had to uindercut the gear which seems to have solved the problem. The best top end i have got out of this motor is 116 kilometers per hour, this however is when the motor was not marvelouysly set up, so may have got more. Bare in mind that this bike does have a an Athena 290 big bore kit