WR426 overheating after cam retard for YZ timing

4 replies to this topic
  • Chaddlez

Posted December 25, 2012 - 04:17 AM


Hi Guys,

I brought this bike a month ago and was running well old owner couldn't tell me if the valves had been checked, So i took the cover off and checked the valve clearances and got them to spec, now i retarded the exhaust tooth by 1 tooth put it all back together and she fired up on 2nd kick (Still getting used to De compressor) pretty hot day like 37 degrees and i was in the garage so more like 40's anyway i let it idle for a while then gave it a few squirts to check there was no back firing etc. then i noticed she was overheating within 5 mins roughly

i have attached picture of what i think is the right cam settings.

Posted ImagePosted ImagePosted Image

[color=#282828][font=helvetica, arial, sans-serif][background=rgb(252, 252, 252)]sorry guys the first picture is what i have set it at the 2nd picture should be stock wr timing correct? and the 3rd picture is how it was set before i touched it [/background][/font][/color]

[color=#282828][font=helvetica, arial, sans-serif][background=rgb(252, 252, 252)]Please give some feedback i think that the cam chain may be stretched but then again ive heard the yamy mechs were a lil lazy with the punch marks on the 01 wr 426's[/background][/font][/color]

[color=#282828][font=helvetica, arial, sans-serif][background=rgb(252, 252, 252)]all picture are at TDC with cam lobes facing out of course,[/background][/font][/color]

[color=#282828][font=helvetica, arial, sans-serif][background=rgb(252, 252, 252)]Thanks guys look forward to your response[/background][/font][/color]

  • Chaddlez

Posted December 25, 2012 - 04:55 AM


I forgot to mention I had to put oil in bike prior to starting as silly me left the plug to rotate to TDC out over night and found a puddle on the floor

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  • Chaddlez

Posted December 25, 2012 - 07:17 PM


Started bike 1St kick today the header pipe started to get hot in less than 30 second think I'm going to put it back to how out was when I first pulled the cover off

  • swolf

Posted December 25, 2012 - 09:09 PM


I have an 06 450 so i could be wrong here but compared to my bike it looks to me like:
pic 1 both cams are retarded a tooth or your not on tdc but on the timing mark at the crank. it will move around a little.
pic 2 looks correct
pic 3 looks like the intake cam is retarded 1 tooth.
make sure its not on the timing mark but on actual tdc. you might have to hold it there because i have seen them rotate a little when you let go of the wrench. its normal for the exhaust header to glow a little when just sitting in the garage not moving.
let me know what you find. p.s. its -14C here and lots of snow so no riding... wish i was there

  • Chaddlez

Posted December 26, 2012 - 03:19 AM


Hi Swolf,

Definitely on TDC there is a HI on the flywheel and instructions are to be on the I and also have checked the piston height with a screwdriver/ straw ect.

I changed it back to the way it was when i first pulled it off i keep you guys updated.


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