Another yz426 cold start thread

I have read numerous threads, but can't really find any info that may pertain to my specific scenario. I just replaced my piston/rings in my 02. I installed a hot cams auto decompression while I was at it. I also changed the valve shims while I was in there to get everything in spec. Before with the decomp lever I could start the bike on 1-3 kicks. Now, it takes about 5-6+ when cold. What else could be contributing to difficult cold starting? Could it be electronics? The spark plug was replaced about a month ago, but I'll probably change it out to a cr8ek or whatever it is just to see if that helps. The pilot jet in the carb is a 42, the needle is in the middle, and I don't recall the main jet and other jet, don't think they'd matter anyways. Anyone have any ideas?

Even with an auto decompression cam, there is still a "drill" of sorts to starting the bike.  Much simpler, though; push the kick start down to where the engine runs up against compression (the "hard spot") and stop, bring the crank back up to the top and kick.  Don't overthink and try to work past TDC or anything, just kick right from the beginning of the compression stroke as you feel it.  


The other thing that you may need to start doing is priming the engine when cold starting by giving the throttle a couple of twists before you kick.  Cold only.

I noticed with my bike when cold Ill give it a kick with a blip of throttle, then another without it'll usually start or at least pop. If it doesnt i give it another kick with a little blip, again itll pop or start. give that a try! 

Awesome, thanks for the tips guys! I didn't realize I still needed to sort of find TDC before kicking it. That is probably my issue. Will try that next time I start her up!

I rode a 426 for awhile and it was very tempermental about starting technique. Try cycling the engine a few times with the kick starter. Get it on compression Then one good kick from the top. No throttle.

Had excellent results with this technique when the bike was hot as well. I didnt even use the decompression lever unless it didnt start on the 1st or second kick after being dumped.

Edited by NW Briff

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