Need 4 stroke help...yz426/yz450f

[LT250Racer609]

I will be the first to admit, Im new to the 4 stroke world. I have owned 2 strokes all my life, and I never wanted to own a 4 stroke, until I needed too a few years ago. Long story short, I have never had one open.

now, My quad is a prp 250r frame, with a yz426f motor with a Athena 444 big bore. I have the motor out of my quad, sitting on the bench to finally replace my 5th gear shift fork I bent 3 years ago, and here is where I get confused....

I know the top ends on the wr400/yz426/yfz450 are all interchangeable. My motor, being a 02, I am not sure if the shift forks/transmission gears are year specific. Basically, Im wondering if 01 yz426f shift forks, will work in a 02 motor? everywhere I look, it just says 01.

I also am aware that there are a few years that the yz450f dirtbike motor was a 4 spd. I wouldnt mind making my 426f based motor a 4 speed. It has the power to pull it, and my gears would be longer...Can I do this?

[chopp124]

4 speed and 5 speed cases wont work together. 2nd gear in 426 is 1st in 450. shifting through neutral sucks on a 4 speed. although less moving parts, not much different. you can use 01 and 02 forks together. they have same part numbers except one but probably same just made it different and changed part number. happens all the time. a 450 head cant just go on a 426. crank chain, piston,cyl,and head has to be used. i have 2 450 and 1 426 hybrid. i can double check that though.

[josborn]

The shift forks are different!! I thought they would be the same when I had a 426....Wrong! You must get 01' forks for the 2000/01 engine. the 02' 426 had its own forks, and none of it will interchange with the 450 transmission. My 450 transmission only has 2 shift forks.

If anyone wants a brand new set of 02' 426 shift forks, I still have them. $50 shipped for all three.

[chopp124]

fork 2 5be18502-20 is the same for both motors. fork 3 5be18503-20 is the same for both motors. fork one is 5be18501-00 for 01 and 5be18501-20 for 02.

[hontrx265r]

I also have a couple of complete transmissions. If your interested. Along with tons of 426 parts I'd like to off. Cases, Ported heads, New valves in the package. cranks, etc..

[LT250Racer609]

thanks for all the info guys. You guys cleared up exactly what I was wondering about. Thanks.

Josborn, I will take those shift forks, but I wont be able to paypal you until friday if thats ok with you. If you dint mind waiting until friday, just send me a PM before then with your paypal address.

[LT250Racer609]

Originally posted by hontrx265r
I also have a couple of complete transmissions. If your interested. Along with tons of 426 parts I'd like to off. Cases, Ported heads, New valves in the package. cranks, etc..

thanks for the offer. My motor is flawless besides the bent 5th gear shift fork, other wise I would pick up some parts from ya.

[josborn]

pm sent!

[hartwill]

While on the 426 topic, mine stopped running. When I would kick it over it felt like a two stroke with a bad crank. Like it had a bunch of drag, also there was some metal shavings in the oil filter. so I opened up the motor and the timing chain was super tight so I loosened up the pensioners and now everything seems normal. Anyone had this happen before? I dont have it all back together yet so I'm wondering if I'm missing something that's maybe broken or something. Thanks. And sorry for stealing the post.