I'm still dialing in my carb. Last night after a ride ,I pulled my plugs to see what they look like and the rear cylinder is running leaner then front ? I remember reading that the rear typically runs richer.I don't believe I have any intake leaks. Checked for leaks a few weeks age. Any suggestions ?

Jim

 

All I can think of is an intake manifold leak on the rear cylinder or perhaps a valve on the rear cylinder is not sealing?

Maybe time for a compression / leakdown test to see if your rings / valves are OK.

 

Yes, typically the rear will run leaner because it is not in the air flow.

In sport bike 4 cylinder modelsthe middle two cylinders are always jetted richer than the outer two.

In off road atv's the rear cylinder (on machines with two carbs) the main jet is always larger.

 

I may look for a leak again but I am not sure. I figured it may run leaner from lack of air , but as I said I read here it was set up richer.

 

I figured as you said. However I wasn't sure thanks.

 

The rear will be lean from MORE air, hence the suspicion that its an intake leak.
Since HD is a single carb bike, the 2 cylinders cannot be individually jetted.
What color is the rear cylinder lug exactly?
If you don't have an intake leak on the rear cylinder, you may have a situation where the rear cylinder is correct and the front cylinder is darker due to oil burning, from the rings or from the intake valve guide seal.