[harley89]

Ive got a 89 softail custom. I had it dyno tuned 3 months ago and havent rode it since. i went to go for a ride warmed it up then it started to run ruff i pulled the sparky's out and they were black with carbon build up gave a kwik clean. replaced old fuel with new bp 98 octane unleaded started her back up run good at first then started to run **** again with the same problem any ideas much appreciated. Ive been told i should use 91 or 93 octane fuel not 98 octane thats why its getting carbon build up.

[wblanton]

Sounds like it is running very rich. The book will tell you to try turning the enrichening screw all the way in, just to wher it seats, no force or you could damage the screw. Then back it out 1 1/4 turns. That is the 'factory' setting.
I had a similar problem last year. Only I went way to big on jetting. Try the setting I just described asa starting point. And try new plugs, cleaning works for light crud but if it is thick and sooty, I would use new.

[kenfuzed]

Could be a combination of overly rich jets installed and/or the mixture screw set too far out like previously mentioned.

"Tuned" means a lot of different things to everyone, do you know what exactly the shop tuned for you? Jets, mixture, different needle, shims, are all changes that could have sent your mixture over the edge as far as being too rich.

[Art_NJr]

Originally Posted by harley89

Ive got a 89 softail custom. I had it dyno tuned 3 months ago and havent rode it since. i went to go for a ride warmed it up then it started to run ruff i pulled the sparky's out and they were black with carbon build up gave a kwik clean. replaced old fuel with new bp 98 octane unleaded started her back up run good at first then started to run **** again with the same problem any ideas much appreciated. Ive been told i should use 91 or 93 octane fuel not 98 octane thats why its getting carbon build up.

[COLOR="Navy"]Dyno-tuned by whom? Not interested in the particular person(s), just their qualifications. Going for max HP & torque is one thing - going for a nice powerband you can actually use on a daily basis is another & 2 things come to mind right off - 1) air/fuel mixture & ignition timing to make top-end power was not right for the riding you actually do & 2) vibration and/or heat messed up intake/exhaust gaskets/seals. Going to a higher octane gasoline (unless from unleaded to leaded racing) will not cause carbon problems.[/COLOR]