WR400 convert to YZ426?

WR400 melted down. Can I drop in a YZ426? will the upgraded stator from the WR400 drop in and power the Baja Designs kit? Is the YZ426 transmission too narrow for dualsport? Thanks in advance for your opinions. I did a search and couldn't find the answers.

DickM

More involved than what you think, to switch the engine to a YZ, you need to switch the harness and electronics as well, and I believe the WR stator does not fit the crank of the YZ.

IMO - the YZ tranny is too narrow - it's an MX bike.

WR ignition can be made to work in a YZ...at least on the 426's...it was a fairly common mod. Look for the "Pink Wire" mod for details. Also, look at the part numbers for the WR400 and 426 flywheels to see if they are the same. If they're not, it doesn't mean it's a no go, as the 426 ignition put out more watts than the 400, so may need bigger magnets as well as bigger coils. You don't need a new CDI box, the grey wire mod changes from WR to YZ timing. The carb, pipe, etc are a bit better from the YZ426. Without a doubt, though, the YZ tranny is too narrow for DS if you do any hiway or fire roading. I have a bud with a DS'd YZ426, and he always has a hard time keeping up on the really fast stuff. You can, however, drop the WR trans into the YZ cases, or drop the YZ crank, top end, and clutch into the toasted WR motor.

thanks for your responses; With the additional input, Ive decided to fix the head and go with the 420 kit. Already has the plate and baja designs kit, so hopefully it will be worth salvaging.

WR and YZ flywheels are different but you can use eather one. I was looking at using the wr flywheel and stator on a 99yz400 that the flywheel and stator melted down on.

the 400 and 426 have different sized wrist pins and since you can't get the rod off the crank, you'll have to replace the crank to use the 426 piston.

You're should be looking for the "grey wire mod", not pink.

If you're just replacing the entire engine, the mounting brackets are the same for both bikes. You'll want to put the WR tranny into the YZ engine if you do.

the 400 and 426 have different sized wrist pins and since you can't get the rod off the crank, you'll have to replace the crank to use the 426 piston..
The rod can be replaced. A connecting rod kit is available from Yamaha and Hot Rods, among others. A press and set of "V" blocks are required. Most shops will do this for between 100-150 bucks.
You're should be looking for the "grey wire mod", not pink..
Geey wire mod changes WR ignition timing to YZ timing. Pink wire mod allows you to run a WR ignition (with lighting coil) on a YZ
the 400 and 426 have different sized wrist pins and since you can't get the rod off the crank, you'll have to replace the crank to use the 426 piston..
The rod can be replaced. A connecting rod kit is available from Yamaha and Hot Rods, among others. A press and set of "V" blocks are required. Most shops will do this for between 100-150 bucks.
You're should be looking for the "grey wire mod", not pink..
Grey wire mod changes WR ignition timing to YZ timing. Pink wire mod allows you to run a WR ignition (with lighting coil) on a YZ

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