Popping On Deceleration. Pop, pop, POW!

Not really...just little ones here and there.

So, when you get a series of pops out the megaphone when letting off the throttle and decelerating (or one pop between up-shifting gears), does that indicate the fuel mixture is rich-too much fuel?

:whistle:

Coasting with the throttle closed is a much leaner situation compared to accelerating. So if you are overall lean, especially just off-idle, it will show up as popping on decel.

But air leaking into the emissions system has the same effect and is notorious for popping on decel. Make sure all of that stuff is sealed off and not malfunctioning.

I did drop the pilot jet size to 15 from 17.5 yesterday.
She runs much better with that leaner fuel jet. Next I will try different air jets and see what happens...smaller = richer is my understanding.

:blink:

Yep, mostly in the lower end.
Steve

I don't remember what carbs you have, but I think smaller is normally leaner.

My bike used to pop occasionally with the stock exhaust. It happened quite frequently whenever my cross over exhaust pipe had a leak at those goofy flat / round gaskets. I assume from the air that was drawn into the exhaust gasses.



I still notice a pop occasionally since I installed my delkevic SS system, but I have not blocked off the air porting for the stock emission setup.. This system allows filtered air to be drawn into the exhaust ports to allow an "after-burn" of hydrocarbons in the exhaust, and hence reduces hydrocarbon emissions. It uses no HP that I know of, therefore there is no reason to disable it.

This is the setup I have. The emissions system is gone, except for the breather hose connected to the air box. Without that, the fumes were nasty when idling at a standstill for any length of time. So back to the air box, sort-of.
The carbs are Mikuni RS34, which have multiple fuel/air adjustment options compared to CV BS34's.

That is such a gorgeous bike Dave.

Anyway.. the identifier numbers for carb jets generally refer to the size of the orifice. You leaned it out a tad with smaller pilots. Like Steve said, they mostly affect the idle passages and lower revs. The main jets have the most effect in the overall fuel mix.



Remember, lean is mean, but it also causes overheating and contributes to blowing sh_t up. Your pipes still look pretty good (not burnt blue yet) That will change if you lean it out, then run it hard.



I put some #4 washers under the main needles upon the recommendation of a guy online that swears by it. I did this last winter / february to try to fatten it up after adding the Delkevic exhaust, but that is just a band-aid until I can get some #125 main jets .

No eBay APP ID and/or Cert ID defined in Kunena configurationI need the Kawasaki / Mikuni 92063-1102. They are listed @ $7.83 +frt on Partzilla. They are referred to as "racing" jets in the parts list.

I was looking for some #125 main jets for my bike on flea-bay and ran across this ad that calls this a "stage 1" kit. The 37.5 pilot jets do not have the holes in the sides (stock sized pilots?) , and I question the 125 HS jet calibration since these are obviously cheap knockoff parts. The kit also INCLUDES $.22 worth of #4 washers (fastenall) referred to as "needle spacers".