Exhaust port colour

mr hunt

Living Legend
Joined
Apr 23, 2013
Messages
2,906
Location
Perth, WA
Ride
2013 Roadster
ok experts have at it....(the only clue is the pix are cyl 1 then 2 then 3):

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Seems similar to mine when I tore it down for the Carpenter project. This was running on a dyno tune, (header and Ramair). Typical for averaged tuning.
 

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looks worse than about 2 yrs ago when I last rebuilt a trans. but the colour pattern is the same
 
My only thought is a/f mixture but coukd it really be that different between cyls?
Certainly can! Since most tune the Rocket with averaged fueling, this is a logical outcome. Heck even old carburetor bikes had richer jets on the inboard cylinders.

In our case the rear cylinder gets the brunt of the heat. Per cylinder tuning will alleviate the varied per cylinder AFR. Since none of the aftermarket pipes are bunged on each cylinder it’s more challenging to get AFR on each cylinder. Tuneecu has per cylinder tuning capabilities, I’d certainly like to have my bike tuned again per cylinder.
 
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