WR cam timing

1 reply to this topic
  • DFuller

Posted February 15, 2009 - 06:00 AM


I have heard of some people changing the cam timing on their yz400 to wr cam timing. I was just curious about the reason for this and if it is better for the machine and if so, is there any one out there that could give me the stepps on how to complete. Thanks, Darren

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted February 15, 2009 - 08:12 AM


This works on the older engines that don't have auto decompression only.

Basically, the cams in the WR and YZF models had the same profiles, they were just timed different. The difference adds up to a higher revving, more powerful engine on the YZF, and an engine in the WR that runs more smoothly at low rpm and has a bit more low speed torque. You might like the WR timing if you are primarily a trail rider working in very tight stuff, or just don't ride very aggressively and don't really wring the bike out that much. You will loose some snap from mid range on up. "Better for the machine"? No. No difference one way or other, really.

Basically, all you do is advance the exhaust cam one tooth. Line the engine up at TDC, remove the tensioner, find the "E" mark on the exhaust cam and make a mark with Sharpie one tooth clockwise from it. Lift the cam out of place to lift the chain off the sprocket and rotate the cam one tooth counterclockwise from its original position and set it back in place so that your new timing mark is now lined up with the head surface, and the "E" is one tooth farther advanced, forward, to the left, counterclockwise from the original factory timing.

Be sure to read the manual regarding handling the chain tensioner, and be very careful with retorquing the cam saddle cap.

Related Content


Wilson the Blue Privateer by jetfuel

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.