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If my pipes in about 1000 miles ,moderate running ,changed to a golden brown color (no bluing), about 6-8 inches from flange, is my bike running lean or rich? I have a 2001 Fatboy that is on its third set of pipes now.I started with D&D slip-ons terrible fitment,went to Cycle Shack drags,not bad but cheap pipes,and now ultimately bought Vance and Hines Longshots that are not on yet.If its any help I have a Screaming Eagle air cleaner,stock carb jetted with a 180 main, 45 slow jet,idle mixture screw about 3 1/2 turns out.Any help to richen /lean would help.Thanks.Hippo you out there?
 

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Discoloration in chrome means heat, not rich or lean. First they turn yellow and then if they get even hotter they start to turn gold to an ever deeper blue.


Where they turn color can give you an "indication" on wether the bike is rich or lean and to what degree.

Generally speaking a pipe discoloring much near the header pipe flange at the head means lean and if it happens further back in the canister it means rich or afterburning due to reversion or an air leak in the pipe. It is also going to discolor at a spot where there is a restriction in the system even if the bike is jetted right, like for example the collector of a 2 into 1. Engines with cams that have a lot of overlap or with too late ignition timing will discolor the header pipe even if the fuel mixture is spot on

No matter what you do they are always going to discolor slightly unless they have some sort of internal thermal coating or if they are ridden extremely hard for a period of time. It's not a science, more of a judgement call you make observing and listening to the bike in question.

When you put pipes on you have to wipe them down with alcohol and then heat cycle them a couple of times. Any oil or fingerprints on the pipe will burn in first time you start the bike.
 

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If the carb is stock meaning it has the stock needle, I'll bet you are lean.

With the stock 2001 needle at the stock height the 45 is close but the 180 is way too small as they come from the factory with a 190

Impossible to say without a dyno, but I guess either the 45 or a 46, the needle raised about .020" and a 190 to 200 main would be closer, but you have to play with it.


(all the jets being Keihin jets)
 
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