nd4spd68
05-21-2010, 06:49 PM
A little history on my '00 K12RS w/ 70k on the clock - 4 weeks ago, while at highway speeds I had a slight failure... Lower nut on the first exhaust cam bearing cap came loose - wedged itself between the exh cam sprocket and blew a hole in the timing chain cover. Also cracked the exhaust cam where the sprocket mounts. So, I replaced the timing chain cover, exhaust cam shaft and the chain guide between the two cams (no signs of any damage to the chain). I also replaced all of the cam bearing cap retaining nuts (w/ a dab of blue loctite). The exh cam sprocket was never removed from the chain during the entire procedure - I double tie strapped the chain to the sprocket to prevent it from jumping, as well as made sure the engine did not rotate in any way. The valve lash is right at the loose limit, but within spec.
Here is the problem - the bike is difficult to start, once it does start, it does idle around 1025... However, it used to start quickly and actually rev in rpm and settle out at 1050ish. Throttle response off idle seems OK. I tried starting it while cold & hot - they both seem to be the same. Also, I went for a ride - now every time when I stop and pull in the clutch, the r's drop to 800 pretty quickly and very, very slowly work their way back up to a bit over 1k. The bike pulls pretty strong and runs smooth at cruising speed, around town - but it does seem to be a little weaker than I remember when doing a top gear roll on, or at WOT in the higher r's.
Some things to consider - since I replaced the timing cover, my original marks for the hall effect were gone. In hopes that the casting/machining would be pretty accurate, I scribed around the two magnetic plate mounting screws creating two half moon marks to reference for install. Obviously not the most accurate way - but I figured it would be close enough to start with. I have advanced and retarded the plate a bit to see if either direction would improve the starting/idle issue - no luck. Now that I have messed w/ the hall effect (which I've heard was taboo), I'm wondering if it is not working properly - although I assume it either works or it doesn't. Could the timing have such an effect on the idle speed - or could I have two seperate unrelated issues....?:dunno What is the best way to verify the static ignition timing?
Any thoughts - input would be greatly appreciated...
Mark
Here is the problem - the bike is difficult to start, once it does start, it does idle around 1025... However, it used to start quickly and actually rev in rpm and settle out at 1050ish. Throttle response off idle seems OK. I tried starting it while cold & hot - they both seem to be the same. Also, I went for a ride - now every time when I stop and pull in the clutch, the r's drop to 800 pretty quickly and very, very slowly work their way back up to a bit over 1k. The bike pulls pretty strong and runs smooth at cruising speed, around town - but it does seem to be a little weaker than I remember when doing a top gear roll on, or at WOT in the higher r's.
Some things to consider - since I replaced the timing cover, my original marks for the hall effect were gone. In hopes that the casting/machining would be pretty accurate, I scribed around the two magnetic plate mounting screws creating two half moon marks to reference for install. Obviously not the most accurate way - but I figured it would be close enough to start with. I have advanced and retarded the plate a bit to see if either direction would improve the starting/idle issue - no luck. Now that I have messed w/ the hall effect (which I've heard was taboo), I'm wondering if it is not working properly - although I assume it either works or it doesn't. Could the timing have such an effect on the idle speed - or could I have two seperate unrelated issues....?:dunno What is the best way to verify the static ignition timing?
Any thoughts - input would be greatly appreciated...
Mark