Rode 75 miles the other day. First real ride since I installed Dynojet, K&N, and DG snorkle. 1st half of ride bike ran pretty good but seemed like it could have been a little more crisp. 2nd half of ride engine would briefly bog down after letting off throttle then getting back on it. Even less crisp. I figured it was too rich so I raised the clips to #4(wason #5 per Dynojet). Now I am too lean. Lots of carb coughting and popping. What gives? Could the wet weather have had something to do with the seemingly rich condition? Should I go back to 5th notch and gut the muffler? How about dropping a size on the main jet and 5th notch on the needle? Could the mixture screws cause the rich condition? Any help appreciated.

 

Those little washers are for finer adjustment of the needles (my DJ kit has them). Use them, make sure you know where they were remove the needles.

Always jet the mains first (using the run fast, turn off immediately, then check plugs method). You should not use plug readings to set the needles or the idle. That only works right on the mains. Never second guess the main jets based on what you do with the needles. Adjust the air screws before messing with the needles.

If it bogs worst when hot while stabbing gas, needles are rich. If it pops bad when cold and doesn't go away unless it is really hot, they are probably lean. It should pop some when cold, but it should go away long before the engine gets to full hot. It should never run really well in cold weather, if it does it is too rich.

 

My plugs were pretty black when everything was stock. Do I need new plugs to get an accurate reading or will they clean up if jets are spot-on? If new plugs are used how long will it take to get a good read? Can I run the bike in neutral to do a plug chop or does it need to be under load? Do the mixture screws need to be re-adjusted after making a change to the main jet or needles? Sorry for all of the questions but I really want to get this right.

 

Old plugs will clean up in a few mintutes of full throttle if the mix is right, as far as I know. New plugs will work too. You have to be under load to do it. Make sure you hold the throttle down past 1/2 for a few minutes and then just kill the engine before you slow down and then coast or brake to a stop. I suggest riding for a while before you pour the throttle on for the plug test just to make sure it is good and warm.

Adjust the idle jets whenever you want. Technicalley, they should be adjusted before you decide to change the needles, but they should be adjusted again after you adjust the needles.