I thought I'd post some info for you guys.
I just bought a '99 KX500 2 days ago and have some printed info on jetting. My bike has a new top end, entirely new cylinder (not resleeved), Revloc auto clutch, ect.
The info I have says my plug gap is: 32/1000
Stock jetting 168/58
Jetting set at 165/55
My factory manual says stock is 175/62
I imagine that would be way too rich, unless you compensated by using a high needle position. The stock needle position is 3, indicating that's probably too much jet from the factory, especially for high alt.
I do know quite a bit about tuning from jetting multiple bikes over the years, as you go up in elevation you need to lean out the mixture. I am in South Texas, RIGHT AT sea level. 165 seems good, although I will probably move the needle up one position (lower clip position) to richen it up just a bit.
I've been doing research for a few hours on surging on decel where the engine will keep kicking even if the throttle is totally cut. This is a little bit dangerous if the terrain is technical and you're not going in a straight line.
WOULD GOING TO A LARGER PILOT JET SOLVE THIS PROBLEM?
Surging on the low end is a sign of being too lean, would simply swapping out to a larger pilot solve this issue?
I haven't had my bike for more than a few days but when I cut the throttle I want it to stay cut.
The only other issue I have with my bike is poor idle.
The plug it calls for is a BR8EG
It comes pre-gapped at .024
A wide gap like .032 is out of spec according to the manual and will draw a lot more energy from the coil for it to fire.
So what I'll do is I'll get a BR8EG and gap it out to the maximum suggested in the manual, which is .7mm - converts into .0275"
I'm hoping that will allow for a lower, more stable idle.
http://www.ngksparkplugs.com/apps/motorcycles/make4.asp?id=4269&type=regAs for the hiccup/surging/kicking when the throttle is cut, I have a hard time believing that is something these bikes "just do", I know with 4 strokes they come calibrated lean from the factory and popping on decel is very common, richening up the pilot will solve that. Will richening the pilot on this bike prevent it from surging on decel?
Would turning in the air screw a half turn improve this?
It's too late to go outside and experiment, or I definitely would.