Tore off heads for porting tonight. front exhaust valvelighter than rear. Whats this telling me?

 

Well, alot of V twin guys will tell you that the front and rear heads generally run at slightly different temps due to the fact that the front head is in the wind more of the time. and the rear is slightly shrouded.

That is just the nature of the beast. HI tech EFI modulesand modern HP ignitions help equalize the temps with mixture and timming.

 

SO NOTHING TO WORRY ABOUT?

 

If the front is just a shade or 2 lighter brown, probably no problem. It therear is black and sooty it could indicate a worn valve guide/seal(oil leaking into cylinder). Normally the rear will be lighter because it runs hotter. Am not familiar with EFI so this may only apply to carbed engines. It does "indicate" the front is running leaner for some reason.

 

Will the porter notice this when they get them?

 

I would attach a note to theheads, it's likely the porter will just do the rebuild without noting the valve color. He might respond if you make a point of it.
If you have pulled the jugs/pistons you might look for blow by discoloration in the cylinders, you could have a worn or cracked ring. Most people will keep the pistons in the cylinders if not replacing them, it saves the breakin you already have, but by sliding the piston down but not exposing the rings, you will be able to see most of the top area of the cylinder.
To me it is just unusual to have the front valve lighter than the rear.