Thread: Yamaha WR400F
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Old 09-19-2012, 06:49 PM   #158
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MingRidesBikes's Avatar
Joined: Oct 2010
Location: Boise, ID
Oddometer: 200
Originally Posted by yamahaman View Post
I have got a Hybrid yz/wr motor and I have tried everything with some good sucess and some bad! From personal experience the 450 cam is Not Quite right. If you can afford it, the hotcams (no affiliation) cams specifically for the 426 in the yz is really good
more power, easy starting and no stalling when brake sliding due to the auto decomp

The bk mod

Make sure you have this matching carb with the red hot start button

The last option is the Vortex ignition I am friends with the owner of vortex and he has given me one of these that is tuned for the wr lighting coil/stator and it has a max power tune and a max tourque setting awesome

These three mods will give you all you need to give the bike all you can without loosing reliability

I have had Standard yz pipe, Titanium DSP pipe, FMF and also currently running a CRD pipe the power is un-noticable between all of the aftermarket pipes, just keep the yz its neat, works ok and not overly loud.

I also have mixed the yz and wr grearboxes to make a custom box 1st wr 2nd yz 3rd yz 4th yz & 5th wr (this was popular with the european enduro guys when the bike came out)

I have run the wr box and yz box, I have found the yz to last the longest and be the most useable in the woods where as the wr box is a bit better for the open stuff. Be aware these bikes are suseptable to fifth gear not holding due to loading up the gear and not reving it out dont labour the bike in fifth keep it on the boil and the gearbox will last

I have done heaps of work on these motors and have come accross all of the major problems that can be encountered with them, great bikes if you know there limitations and more help pm me

Thanks for all the info! I'm gonna be reading into the carb and ignition mods. Didn't think these would be substantial area's of opportunity. I do need to check the throttle stop screw for sure. I know it has the yz pipe I believe off an 2001? they are different between 01 and 02 if I'm not mistaken. And when doing the hotcams from the 426f, The exhaust is for auto decomp, the intake is where the power comes from correct? Jetting I'll have my shop dial down, is there an airbox mod that actually helps this bike breathe and get more power, or keep it stock?
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