Problem w/ YZ Timing
Posted October 02, 2002 - 07:18 AM
Free mods done, including grey wire, 42pj, 165mj, DRR #3 needle, Yoshi pipe. As I said I tried all kinds of different jetting and it change anything. Let me know what you guys think. Thanks.
Posted October 02, 2002 - 12:13 PM
So either the timing change uncovered a jetting glitch, which is possible I suppose, they do seem to idle a bit rougher with YZ timing, or it could be that your ignition timing is on the verge of being too retarded and the new cam timing made it worse.
I guess if it were me I would leave the WR timing, put a YZ needle in there, rejet for main and main air jet, then try the YZ timing again. In my experience the only jetting change the cam timing change prompts is a slight one on the fuel screw (provided the bike is jetted properly to begin with) due to the rougher idle.
Hope this helps.
Posted October 02, 2002 - 12:32 PM
What is the recommended jetting for an 02 WR426 with YZ timing at sea level? I know it's posted all over the place but everyone seems to have something a little different.
Thanks for the help guys.
Posted October 02, 2002 - 05:15 PM
As for your problem, it does sound like a clip position or maybe pilot circuit lean condition, but as you stated changing these things didn’t help it. If the problem disappeared after changing the cam timing only then I guess it can’t be a jetting problem.
I’m stumped. I have noticed different idle characteristics after changing a WR to YZ timing but no issues at higher throttle and higher rpms.
My next best guess would be that your ignition timing is off, I think I said too retarded but it could also be off in the other direction, and the different cam timing will affect how it runs at a certain ignition advance at certain rpms, this is why the YZ (I’m told) has a different ignition curve. Add in the fact that the ignition timing changes w/ throttle position via the TPS sensor and I’d think that adjusting / testing that sensor may not be a bad idea.
Hope this helps.
Posted October 02, 2002 - 07:16 PM
Hick, Thanks for the idea of testing the TPS. I had thought of that, but wasn't sure if I wanted to mess with it. I guess it can't hurt as long as I mark where it was stock. The only other thing I can think of is to try a YZ or Vortex ignition, but that's a lot of money to shell out without knowing if it will help.
Does anyone know if Stock YZ's have the same sputtering problem at constant 0-1/2 throttle?
Thanks again for your help.
Posted October 03, 2002 - 01:32 AM