i wanted to relay my experience on changing the timing on my o1 wr426. I posted a question on this site asking if the timing needed to be changed in Australian models and the answer i got was a resounding yes. well this is NOT the case for all those in oz with o1 426's.

me dealers mechanic reluctantly performed the job against the advice of yamaha and when finished the bike would NOT start, backfired badly every kick and I had to get him to reverse the change.

they are already yz timed

Should they not have been able to look and see that it was allready timed for YZ upon opening her UP?

The proceedure I followed made it impossible to do it twice. Unless you did not look at what you were doing.

The guys at the shop should have noticed this before they finished.

And if Yamaha was involved? should they not have communicated the timing specs?


were there 13 pins or 12 pins between the marks on the cams? They should of counted this before even removing the cam!!!!

13=WR 12=YZ My guess would be that even in OZ the WR is timed with 13 PINS


C'mon and cut these guys some slack.They live on the bottom of the planet ya know.If you drop a wrench or bolt down there,it'll fall STRAIGHT UP INTO THE SKY!They have to walk around outside with suction-cup shoes and have velcro carpets in thier houses.How can you expect someone to figure out cam timing while working in those conditions? On the up-side,you can easily get HUGE air down there,you just gotta be careful that you don't jump clean out of the atmosphere.


Did they advance the exhaust cam instead of retarding it? Someone did this on the WR250F forum and had the same symptoms. He was mislead on which way the cam timing was to be adjusted and got what he asked for. :)

Have any others in OZ tried the cam timing change?

Yeah, i bet they advanced the exhaust cam one click. I have a WR250F (Aus model) and have changed the cam timing to YZ spec. What a difference! I don't think the WR426 is exempted from this mod, and if anything, it should benifit the most from it. YZ426's power delivery is mega aggressive. WR426's are still aggressive, but not quite as bad. My local Yamaha dealer is clueless, and wouldn't trust him with an oil change, so i reckon they stuffed it!

this is why I learnd how to do this stuff myself

that way its only your screwups that you need to worry about

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