I thought I had my bike dialed in. As I rode to work this morning I noticed a slight jerking (not like a lean surge though) when around 1/4 throttle and holding steadyrpms.Other than that it runs fine. No decel popping, smooth acceleration, and no dipping idle or dying at stoplights (thanks bryantjt for the F/A screw suggestion). I pulled the plug and it looks very much like the one in the attached picture. Right now the clip is in the 3rd groove and the F/A screw is at 1 7/8 turns out. I'm thinking about moving back to the second groove and setting the F/A screw appropriately if finer tuning is needed. Or instead of leaning it out via carb settings should I open up the intake a little?

[IMG]local://upfiles/3485/ECEBD220BED840068369F49B3E77F774.jpg[/IMG]

 

If it were my bike I would install the KDX snorkel before I did anything else.

 

That's exactly how my plug looked when I had the KDX snorkel in and ~ 2.25 turns out. I've since gone to no snorkel and am still fiddling with the A/F screw but its back up near 2.25 and its a nice light tan color.

 

Were getting the light surging? At least it looks like I'm in the fine tunning stage now. I'll pull out the snorkel and test it out on the ride home.

 

fine tuning stage?

You have a whole list of things to change for the better (refer to the 4 page previous thread)

 

I know. I'll never be done improving the bike (that's part of the attraction). I just meant fine tuning to get the mixture right. On that note, I changed to a new plug and rode home w/o the snorkel. Checked the plug and it was also carbon fouled after the ~ 12 mile ride.I put the snorkel back on, set the clip on the second position. No more surging and no more carbon fouling. At least on thetest ride. I'll have to put some more miles on it to be sure. I didnotice something curious when resetting the clip position.When I pulled the top of the carb off it smelled strongly of gas and the white plastic spring holder had fuel on it. It was definately running rich. If it doesn't behave well now I'll look into the posibility of a bad diaphram or seating...

 

It sounds like you have a grip on the situation.

 

That could be your problem....did you soak it in hot water while working on the carb?

 

I didn't soak it at all. The directions from HMF say "... As soon as you remove the slide/diaphram soak it in HOT water, if you don't the rubber will expand to a large size that you will not be able to get back in the groove."

Correct me if I'm wrong, but soaking it in hot water would not keep it from expanding. It would do just the opposite. I didn't have any problem getting the edges of the diaphram seated in the groove when I reassymbled it. Although I've paid close attention to the diaphram seating, it is possible that its not seated properly now after having pulled the top so many times to adjust the clip.

 

When I was rejetting the CVK (or other CV carbs on other bikes), I have never soaked the diaphram. Just worked quickly to rejet and reassemble. I haven't had any problems.

However, beware of putting carb cleaner on the diaphram, but that's another story...