Rear cylinder spark plug fouling

[kosmik]

I have a 1993 fxstc with a cv carburetor with 45 and a 175 jetting with stock needle and the vacuum slider drilled to .125, the bike has the air box cut open for more air flow and non stock mufflers(not drag pipes)and an Andrews ev27 . The idle screw has been adjusted from 2 to 3 turns. The bike will idle with the screw all the way in. The bike keeps fouling the rear cylinder.

Help I need to make it to Sturgis.
Thanks

 

[TripleJ]

Is it fouling due to oil or fuel. Considering it is just fouling one cylinder, I would check for good spark and run a compression test and see what you come up with. Also replace with new plugs and not just clean and reinstall.

 

[brownfoxx1]

you can go one step hotter in that cyl.to see if that helps. i did with a 1974 fxe 1200. with no problem.

 

[kosmik]

I have replaced the coil. would a more powerful coil help ? could it be the wires? I guess the rear obviously runs hotter ,but I have not had this trouble utill recently.( 50000 on bike)
Thanks.

 

[HDDon]

If you didn't change the plug wires that would be something I would do now. With 50,000mi. it would not hurt to do a leak down and compression check.

 

[glider]

I agree with HDDon. You can check the resistance in the wires to be sure with a meter.

 

[03ultra45385]

What about a valve seal gone bad, Has oil consumtion increased?

 

[kosmik]

Thanks I will check the wires and compression. The bike does not burn any oil.
KOSMIK