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Krannie McKranface

Which YZ exhaust cam for 2008-2011 WR?

7 posts in this topic

Remember if you use a YZ cam your electric start may not work when cold.

If you use a Hot cam with a proper pin it will work.

The Hot cam is more cammy so bumping the compression up a 1/2 point should help low end.

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Remember if you use a YZ cam your electric start may not work when cold.

If you use a Hot cam with a proper pin it will work.

The Hot cam is more cammy so bumping the compression up a 1/2 point should help low end.

 

I have the Hot Cams intake and exahust cams right now

The cam timing is too early on the intake, and it makes it very cammy

I went to 12:85 piston too, and it is still too upper mid heavy for me.

 

My bike has over 800 hours by estimate, and everything is wearing out

I'm thinking of starting over with a lower hour '08+ WR, and am in the planning stages

 

I have read several posts where the yz ex cam works fine hot or cold, but can't remember if it's a specific year, or what.

 

I believe YZ ex cams from 2006 are different from 2007+ ?

Edited by Kah Ran Nee

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Some info on it. http://www.thumpertalk.com/topic/944161-yz450f-cams-going-into-wr450f-2007-into-2006/

Also I'm wondering if the YFZ hot cams work and there might be one better suited. If not you might be able to send the cam out and have the sprocket pressed off and moved for more bottom end.

Edited by stevethe

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Why not try different maps first?

Just kidding! I remember seeing either here or in the YZ forum (pretty sure here) a whole run down of the various years' YZ exhaust cams that Grayracer had written/compiled and I had it in my head after reading it that the 2006 cam was the way to go for solid across the board gains, and especially bottom end. As I remember, duration inceased after '06 and power moved up in the range. When it's time to do my valve clearances, the '06 cam is what I plan on going with. But my head is not ported like yours, so I don't know if you'd benefit more from a different year.

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I've read in other forums that the exhaust cams with differences are

 

2006

2007/8

2009/10

 

2006 being the most agressive, but also the least 'likely' to e-start when cold

 

The '09 was named as being the least likely to have starting problems.

 

The motor in my WR is going dead, approaching an est 900 hours

Trans, Clutch, Crank, etc.

 

As of this moment, I plan to start fresh with a new bike, and transfer over the 'cool' parts from my bike; I could change my mind tomorrow.....

I don't think I will use the ported head (?) only because of the added expense/hassle to transfer it over to the new bike

 

I've ridden the KTM 350XCFW now on three rides.....BOY do I miss my WR........ :cry:

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I've ridden the KTM 350XCFW now on three rides.....BOY do I miss my WR........ :cry:

You should get a 250f, it will be perfect. Because it makes the C class gncc riders way faster than the 450f riders. You'll love it. You arent a pro so a 250f has all the power you'll ever need. Its all about the rider, remember ?

Seriously, good luck with your engine.

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