Carb Lean and Rich adjustment

[kmalysa]

Okay here is the deal, did all service and installed V&H Big Radius Pipes and S&S Dual runner, replaced plugs and gapped to spec .040 . Set Carb to factory settings and tweeked from there.

Noticing front cylinder plug and pipe is sooting indicating rich, while back cyclinder plug and pipe are clean and dry indicating lean (plug a little white). What would cause the two cyclinders to be so different?

Seems to run okay, with slight decel pop? BTW Jets are.031 and .076. Realy didn't get much riding done before the Mods but even the old plugs were similar.

 

[nine lives]

Front cylinder will run a bit cooler especially in cooler weather. Rear cylinder retains more heat (less air flow) I would re-check the plug gap and do a search on carb settings, you may have to tweek you air fuel screw or re-jet. Make sure you get the bike up to operating temp. before making any adjustments.

 

[narow37]

may also have an exhaust leak or intake leak. check for that.

 

[kmalysa]

Thanks for the help. Front running cooler makes sense. No leaks, carb set at factory, but does need more tweeking. I am going to try to find someone to do a dyno tune.

 

[oldmutt]

I have the same problem. Out of the box the bike had a little decel pop and the plugs looked like yours. Put on BR 2 into 2 pipes and 31 and 76 jets. Got more decel pop and lost some low end power. Plugs looked the same. Yesterday I put in a K&N air filter and went to a 32 jet. I lot less decel pop and more low end power. I checked for intake leaks more than once and nothing. I put in new plugs and I will check them after a few hundred miles. If you figure it out please let me know what you find.

 

[kmalysa]

Went back a re gapped my plugs, they were closer to .036, so re-gapped to .040. Set carb back to factory settings (Super G shorty). Idle Mixture 1 1/4 turns from seated, Accelelrator 2 turns out from seated, then tweaked 1/4 to1/2 more out. Running much better... Will check plugs after more riding. Idle speed set to tach at 1000RPM

 

[oldmutt]

I think this is my problem. When I got the bike the idle mixture was 3/4 out. After the pipes it was still 3/4. Now I had to go in to 5/8 from seated and it runs good. If I go in or out it slows down. I have my idle at 1070 rpm.

 

[kmalysa]

OOOPs I just edited my post. I meant the Accelerator pump adjustment is 2 turns out from seated (factory) then 1/4-1/2 out more. Idle mixtur is about 1 1/4 out from seated, Idle speed about 1000RPM