Roll Starting a 426??

25 replies to this topic
  • Fizz

Posted December 10, 2005 - 01:49 PM


perhaps this is a stupid question, but is it possible to change the exhaust cam only?
(HotCam or OEM?)

  • DigilubeJay

Posted December 12, 2005 - 03:35 AM


Yes, Fizz you can change out only the exhaust cam.

But, changing out to the HotCams adjustable intake cam also provides you the ability to futher tune the beast.

  • Fizz

Posted December 12, 2005 - 03:41 AM


Digilube<- thanks!

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  • Slowbiz

Posted December 12, 2005 - 07:40 AM


No, it cant be done.

  • grayracer513

Posted December 12, 2005 - 08:18 AM


Yes, you can change only the exhaust cam. More than 80% of the people doing this mod have simply used the OEM Yamaha 450 exhaust cam. That cam is itself also a performance upgrade along with adding autodecompression. Most report that it has the effect of smoothing out the hit by beefing up the low rpm power so that the power curve is flatter, and increases mid range power without giving up any top end. As to the quality of either OEM materials or production methods, I put it at least as high as that of the aftermarket. One of the thing the Japanese have become famous for is their adherence to very high production standards. Plus, the grind profile of the OEM cam is likely to be made with more consideration to valve train longevity than an aftermarket part is.

There are only two points on which an aftermarket cam might be called a better piece. One is that the OEM timing marks on the 450 cam are not the same as those on the 426, and as a result, the 450 cam must be timed by using the properly timed intake as a reference. This is only a problem because it requires you to think a little and follow instructions. The other issue is that there is a *VERY* minor difference in the cam chain pitch between the two engines, but literally hundreds of people have run the OEM 450 cam, many for well over a year, and nobody has had a problem with it.

I have not heard of any "automatic" shim change having to do with Hot Cams. I'm not sure what that would mean, but it would not be at all unusual to have to reshim the exhaust valves when changing the cam, although some have found they didn't have to.

  • racer8

Posted December 12, 2005 - 10:15 AM


Very well said 513!!
Many of us have done that mod with no problems.

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