02 426 valve adjustment question


5 replies to this topic
  • 426Braap

Posted May 18, 2007 - 09:19 PM

#1

I'm adjusting my valves on my 02 426 with a yamaha 450 cam for the first time and was wondering if someone could tell me if this looks "normal". The manual says the lobes should be inline and as you can see from the picture they are not. I am at TDC on the compression stroke and both dots are at the top on the chain side.

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  • DTYZ426

Posted May 18, 2007 - 09:24 PM

#2

The first photo looks good to me. I have an 01 426 with the 450 cam and my lobes line up just as yours do while at TDC, for the purpose of checking the valve lash. As for the second photo I can't see it clearly but it appears the intake lobe is pointing the same diretion as the exhaust lobe. What are we supposed to see in the second photo?

Does the bike start and run good?

  • 426Braap

Posted May 18, 2007 - 09:31 PM

#3

The first photo looks good to me. I have an 01 426 with the 450 cam and my lobes line up just as yours do while at TDC, for the purpose of checking the valve lash. As for the second photo I can't see it clearly but it appears the intake lobe is pointing the same diretion as the exhaust lobe. What are we supposed to see in the second photo?

Does the bike start and run good?


Thanks for the fast reply DTYZ.
The second pic doesn't look as good as it does when its a little bigger its just a different angle pic from the first.

The bike starts, runs and idles good except it has a misses when i crack the throttle open. I've been messing with my jetting to try to fix it, but no luck there and I thought maybe the valves were just a little out of adjustment.

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  • Dustin_Mabro

Posted May 21, 2007 - 05:20 AM

#4

I'm adjusting my valves on my 02 426 with a yamaha 450 cam for the first time and was wondering if someone could tell me if this looks "normal". The manual says the lobes should be inline and as you can see from the picture they are not. I am at TDC on the compression stroke and both dots are at the top on the chain side.

Posted Image

Posted Image


I can't see the pictures very well but you said it was the auto decom cam? Was it a OEM 450 cam or the Hot Cams for the 426, if it's hotcams you time them as you would stock, if it's the OEM 450 cam then you'd time it using the 14 pin method......right?

  • grayracer513

Posted May 21, 2007 - 06:01 AM

#5

I can't see the pictures very well but you said it was the auto decom cam? Was it a OEM 450 cam or the Hot Cams for the 426, if it's hotcams you time them as you would stock, if it's the OEM 450 cam then you'd time it using the 14 pin method......right?

Good point. If using the OEM Yamaha 450 cam, position the crank at TDC and checl the timing marks on the intake only. If it is correct, then next check that there are 14 pins of chain between the top, "12:00 o'clock", marks on the cams. This will make the exjaust cam appear to be too far advanced, based on the timing marks, but the 450 cam was marked for a 450 head, and the marks don't line up in a 426.

If it's a Hot Cams, or other cam, that was made for a 426, time it it by the marks like a stock cam.

The picture from the right side does appear correct, BTW, but check it.

  • 426Braap

Posted May 21, 2007 - 01:21 PM

#6

Thanks guys for all the info. It's the Yamaha 450 cam. I had a mechanic friend of mine who knows these bikes look at it while it was open and we were able to get everything back in order and it was TDC. I was in kind of a hurry so I figured I would get it done right and mess with it myself next time when I have more time. Thanks again and as always...Braap it up





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