Front pipe discolors, not back pipe
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Cruiser
Joined: Apr 2006
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Front pipe discolors, not back pipe
Running straight drags with a "lollipop" baffle (90 degrees to the pipe) Front pipe is discoloring (some gold at first, now blue) about a foot back from the port...the rear pipe is not, at all. Both plugs look about the same, pretty good. I checked for air leak (WD-40 spray) seems ok. I am the one with the misfire problem, also.
Thanks
zen
Thanks
zen
Outstanding HDF Member
Joined: May 2007
Posts: 2,304
Likes: 31
From: Florida
RE: Front pipe discolors, not back pipe
There are only three reasons a pipe will turn blue besides a leak.
#1 too rich of a fuel mixture which lets the fuel continue to burn out of the combustion chamber and into the pipe, the heat from this burn will discolor the pipe.
#2 too lean of a fuel mixture which again burns in the pipe discoloring it....now your probably saying that doesn't make sense, how can rich and lean both still be burning in the pipe. Good question. Stoichometric (which is 14.7:1 afr) is a perfect burn....everything in the combustion chamber isburned up at this ratio. Richer takes more time to burn because there is more fuel to use up so it burnsout in the pipe. Leaner than Stoich takes longer to burn too because the fuel molecules are further apart making the burn time longer so it burns in the pipe.
#3 timing retarded which heats up a large part of the cylinderand the pipe will transfer that heat andagain unburned fuel isstill burning in the pipe.
Now I said all of that to say this.....what year is you bike...carb or EFI....what ignition....what cam?
#1 too rich of a fuel mixture which lets the fuel continue to burn out of the combustion chamber and into the pipe, the heat from this burn will discolor the pipe.
#2 too lean of a fuel mixture which again burns in the pipe discoloring it....now your probably saying that doesn't make sense, how can rich and lean both still be burning in the pipe. Good question. Stoichometric (which is 14.7:1 afr) is a perfect burn....everything in the combustion chamber isburned up at this ratio. Richer takes more time to burn because there is more fuel to use up so it burnsout in the pipe. Leaner than Stoich takes longer to burn too because the fuel molecules are further apart making the burn time longer so it burns in the pipe.
#3 timing retarded which heats up a large part of the cylinderand the pipe will transfer that heat andagain unburned fuel isstill burning in the pipe.
Now I said all of that to say this.....what year is you bike...carb or EFI....what ignition....what cam?
Outstanding HDF Member
Joined: May 2007
Posts: 2,304
Likes: 31
From: Florida
RE: Front pipe discolors, not back pipe
Have you had it dynoed tune? I'd check the AFR in both cylinders...maybe adjust the accelerator pump nozzle to squrit toward the frt cylinder or even better yet have it hit the needle so it sprays instead of a squirt gun effect. Hve the ignition tuned while your on the dyno plus those plugs you have in your pipes. Optimize timing and exhaust flow and taking a fuel reading you'll know right where you stand and what has to be done.
Good Luck
Good Luck
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