Cam timing on 2001 YZ 426


4 replies to this topic
  • rmfisher18

Posted March 30, 2006 - 02:18 AM

#1

Hi there,

I have a YZF 426 that I mainly use on trials rather than motocross.

I want to get more low down power from it like a WR.

I have fitted a WR flywheel and I have heard that the YZ has different exhaust cam timing to the WR by 1 tooth.

Does anyone know which way to adjust the exhaust cam and what effect will this have?

Will the stock YZ carb jetting be ok with the cam timing change or will it have to be modded?

Many Thanks
Rob

  • jbrooks26

Posted March 30, 2006 - 02:54 AM

#2

It is possible that you will need to rejet slightly with the timing change. If you count the pins on the chain between the two top timing marks there will be 13 for WR timing and 12 for YZ timing. You will turn the exhaust cam one tooth counter clockwise to achieve WR timing. This is assuming you are running the stock cam. Hope this helps.

Josh

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  • Raven1911

Posted March 30, 2006 - 05:09 AM

#3

Hi there,

I have a YZF 426 that I mainly use on trials rather than motocross.

I want to get more low down power from it like a WR.

I have fitted a WR flywheel and I have heard that the YZ has different exhaust cam timing to the WR by 1 tooth.

Does anyone know which way to adjust the exhaust cam and what effect will this have?

Will the stock YZ carb jetting be ok with the cam timing change or will it have to be modded?

Many Thanks
Rob



Man, what is your gearing?? Instead of looking at the exhaust cam why don't you change your gearing. I too have a 426 and in first gear that thing pulls, can't really understand how you would want more pull but have at it. Look into a bigger rear sprocket by a couple teeth. :thumbsup:

  • rmfisher18

Posted March 30, 2006 - 08:39 AM

#4

Man, what is your gearing?? Instead of looking at the exhaust cam why don't you change your gearing. I too have a 426 and in first gear that thing pulls, can't really understand how you would want more pull but have at it. Look into a bigger rear sprocket by a couple teeth. :thumbsup:


Just want the power delivery to be a bit more smooth. I have ridden a few WR's and the power seems much more usable for the type of riding I do.

Thanks for the help...... :thumbsup:

  • grayracer513

Posted March 30, 2006 - 09:13 AM

#5

Reverse the procedure shown here:

http://motoman393.thumpertalk.com/

DO NOT do this modification on an engine equipped with auto decompression, whether OEM or aftermarket. It will throw off the function of the AD mechanism.





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