Sparkplugs - need a diagnosis and prescription

[JerryH]

Sorry no pics available.

1997, standard, 45000 miles, last plug change at 40,000 miles (plugs looked the same then as they do now).  MPG - around 33, Jardin pipes (had Cobra 6 packs on it till I bought it).  Was told the mechanic installed the Cobra "Jet" kit when the 6 packs were put on and shimed needle to #4. 

Plugs #1, 2, 3 - look OK, nice clean tan color.
Plugs #4, 5, 6 - look terrible, black and sooty.???

Bike has recently started to "pop" on deceleration???

Installed a Pingel fuel valve a  month ago and plugged the Vacuum line going to #6 carb.

checked the clamps on the intake "tubes" all were loose - tightned all back down.


what does anyone suggest for a fix?

If anyone mentions "get into the carbs" for that shim.  Does anyone have a step by step to do that.  I do all the maintenance on the valk and pervious Wing, but carbs are not my strong suit.   However, I am willing to try.

Jerry

[Cliff]

If I understand correctly the good ones are the front two ones on the right side (as sitting on the bike) and the front one (2) on the left side?

[JerryH]

You've got it right Cliff.

Jerry

[sandy]

The needles being "Shimmed" to the #4 position is too rich. That may be the reason you only get 33 MPG. After starting on position #3 I dropped them to #2 down from the top and opened up the pilot screws to 2 1/4 turns out from lightly seated. Now I get 36-37 and it runs great. I need a bit of enrichment on cold mornings which is normal. I have Thunder Valley headers with custom made silencers.

[JerryH]

thanks Sandy - that sounds like my next plan.  Now - anybody have a step by step (maybe pictures) of getting inside and adjusting the shim??

Jerry