Valve Timing issue, Pic's included
Posted June 07, 2010 - 01:00 PM
I put the engine to TDC as per the manuals instructions, and the cams look like this:
Now keep in mind that I've done all the free mods, including the yzf cam timing mod, in which I retarded the exhaust cam by 1 tooth.
In these pictures the crank is PRECISELY lined up at the TDC mark (flywheel/case), and I checked before and after each pic.
I'm only concerned because the manual depicts the cams being in a different orientation, i.e. the lobes should be EXACTLY lined up with the head/valve cover sealing surface, and the "I" and "E" should be in the 3 and 9 o'clock position and the dots should be at the 12 o'clock...again, understanding that I've done the yzf cam timing mod the exhaust cam should be slightly (1 tooth) different than the picture in the manual.
The bike runs mint, starts 1st/2nd kick cold, with choke, 1st kick hot, every time. Has a slight rough running condition at steady throttle, noticeable "hit" in power in the midrange, the plug reads perfect.
I should also mention that this bike is a street legal motard, I am the 2nd owner, except for the throttle stop and removal of the peashooter cap from the exhaust, the bike was bone stock when I got it.
here it is now:
Should I fiddle with the cams, or just leave it? I'm just curious if the bike could make some more power with properly timed cams.....
Posted June 07, 2010 - 07:11 PM
Posted June 08, 2010 - 12:28 PM
The only difference between the cam timing of the two engines was the way the exhaust cam was indexed into the sprocket. The intake cam is the same one in both the WR and the YZ, so before auto decompression came along, this was a simple hop up trick.
I should mention that you CANNOT do this with an auto decompression WR because the timing of the decompression cycle will be altered, and the bike won't start.
Posted June 12, 2010 - 08:08 PM
Although I haven't fiddled with cams in years, I remember when I built my blown '78 TransAm in highschool auto shop, we degreed the cams a few different ways with different results. I'd just like to be sure that I'm getting all the power this thing has to offer, in basically stock form.
Posted June 13, 2010 - 01:49 AM