cam timing

4 replies to this topic
  • Trick188

Posted September 22, 2005 - 10:03 AM


I just replaced valves in a 98 WR 400 and am reinstalling the cams but I cant figure out if the "H" mark or "I" mark on the flywheel is TDC? I dont have a manual and have got conflicting reports off the web. Anyone know this off hand for sure?

  • Yamahondaha

Posted September 22, 2005 - 10:30 AM


the "I" mark is the one to use when timing the cams and if you rotate the exhaust cam clockwise by one tooth you will be pleasantly surprised...
For those who don't already know it will be like the YZF cam timing and give the WR a more MX feel. I just did my 1999 WR400 top end and tried the YZ cam timing and loved it. The bike feels the same up to 1/2 throttle. then it rev's out like a two stroke power band. Oh I also have the gray wire cut and a JD needle and jets.

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  • byggd

Posted September 22, 2005 - 01:58 PM


Just as an fyi....the manual says the "H" is used when checking the timing with a timing light :banghead:

  • Trick188

Posted September 22, 2005 - 02:07 PM


ok it was timed right but it has very little compression still (40 psi compression with only 10% leakage). The bike floated the intake valves into to the piston and bent 3 valves so they were all replaced as well as the piston but i'v now got it narrowed down to the intake cam sprocket spinning on the cam so the intake valves dont even close until nearly TDCC. I advanced the cam 2 teeth and kicked it over and it has tons of compression like it should. My question is:

Who has a stock intake camshaft they want to sell?

  • Trick188

Posted September 23, 2005 - 08:47 AM


no one has a stock cam laying around?


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