Center intake valve clearance ?

1 reply to this topic
  • kubamtx

Posted September 15, 2007 - 02:03 PM


Today I talked with few guys working in yamaha services. They've told me that I have to set valve clearance a little difrent then the manual says.
They said that center intake valve should have 0.2-0.22 not the 0.1-0,15 in 01 yzf 426. They say that the same thing is in yzf 250 any year. They say that that's because the center inatke cam lob is engaged 15 deg ealier.... is this true and good to set this clearance at 0.2??

Another question is?
Cam I put 450 cam chain into 426? I know that it is shorter but that's not my problem because I can get tsubaki chains in any lenght. As I found there is only diference in lenght and sidle plate shape. Am I right?

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

Posted September 15, 2007 - 03:41 PM


First question: NO. The cam lobe for the center intake is set at a different angle because the center intake valve is set at a different angle. Under no circumstances should you set the center intake to anything other than .10-.15mm. Are you sure these guys worked there, are were they hanging around the back with a beer?

Second question: NO. The tooth profile of the 450 cam chain is different. This was a big issue that people were worried about during the early experiments with the 450 exhaust cam in a 426 engine. The 426 chain would not sit down into the sprocket teeth as the 426 chain does, and many felt this would prevent the swap from working. Because it is close to the same, and because the cam sprocket is relatively large, and because the chain passes over only a quarter of it, the conversion turned out to be OK.

However, we are talking about a crank sprocket. The chain must cover half the sprocket correctly, and the chain runs over it twice as fast, and over each tooth twice as often. Because of that, I would not run anything other than the correct one.

Related Content


Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

The "going back to the other darkside" adventure... by Monk

Dirt Bike   Make / Model Specific   KTM   250/350/450/505 SX-F & XC-F (4-Strokes)
  • Hot  113 replies

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 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.