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jevc

engine blew up

9 posts in this topic

Yesterday it happend. I blew a hole in the cranck case. inside looks like a mess. any body know where I can get an engine for a 2002 wr 426? The rest of the bike is in good shape with a ton of mods. I got too much into it to just part it out and it has a Ca street tag. Any Ideas. there is shrapnel laying all over the road to my house.

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Get a hold of this guy and see what you can work out.

Join Date: Aug 2001

Location: California

Posts: 1,555

Real Differences tween 2001 YZ and WR ?

I have a 2001 WR426F that has been in supermoto trim since the day I bought it new in late 2000, it has been a wonderful machine.

3 years ago I did a 444 big bore kit to it, had the head cleaned up and ported slightly and it was a definite improvement.

Like all of the after market pistons this Weisco started to rattle around in the bore after a few thousand miles, and I am sure the rod is a little long in the tooth.

Long story short, I was debating rebuilding this WR motor from the ground up when I came across a brand new YZ426 motor in a crate complete with carb, so I bought it, but now I am having second thoughts.

My question(s),

How much different is the YZ gearing than the WR (same year engine)?

Were there any other differences in the 2 engines besides cam timing and throttle stop?

I will need to keep the lighting coil because my bike is street legal so I have lights and signals, do I just swap the lighting coil from the WR motor over to the YZ motor? is there anything else I need to do electrically to do that right?

Also I read allot about counter balancer woodruff keys back in the day, I can say however that my WR motor never had an issue with that, so is there a hardened (harder than stock) woodruff key that I should consider replacing before I put the motor in the bike?

I guess my main fear is that with the YZ gearing I may not like it as much on the street, so I need some input on that from those of you with experience.

I have not committed to anything yet other than the fact that I have a brand new YZ engine in a crate with Japanese writing all over it sitting in my garage, I will not be putting the big bore kit on either of these 2 engines this time around as I really don't think the reliability is there with after market pistons and the extra bottom end that I got out of it was really not worth the piston slap noises I had to put up with after about 6 months of weekend riding.

So the bottom line is this, if you had the choices I have now of (1) installing a brand new engine including swapping the ported head from the old engine, swapping the lighting coil from the old engine and calling it a day or (2) rebuilding the old engine which I am sure will require all new lower end bearings, a few gears, shift forks, clutch basket and clutch, crank work most likely (Falicon), with a knife edge rod etc.

I am certain I can sell this crated engine to a kart guy on ebay and not lose a dime, I paid $1400.00 for it.

I guess the other thing I could do is sell the old engine on ebay for close to a grand and end up paying $400.00 for a brand new engine which would not be all that bad.

Thoughts? suggestions?

Thanks.

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Does anyone know if a 450 engine will fit in the 426. I would like to stay with a wr engine as all my riding is wide open desert and I need the fifth gear. I am going to start tearing it down today to see how bad things are but I am not thinking it is going to be pretty.

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Does anyone know if a 450 engine will fit in the 426. I would like to stay with a wr engine as all my riding is wide open desert and I need the fifth gear. I am going to start tearing it down today to see how bad things are but I am not thinking it is going to be pretty.

l've just fitted a 450 engine into my wr400, there's a few mods you have to do but not to much. l'll post em up when l get time if you want to know.

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