The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: a101960 on 28.08. 2015 15:43

Title: Exhaust pipes colouring
Post by: a101960 on 28.08. 2015 15:43

When returning from a ride my exhaust pipe headers (chrome siamesed) have a very slight yellow tinge. Once everything cools down this colouration completely disappears. The bike runs just fine, but I am wondering wether  this could be due to a timing or carburation problem. Anyone have any ideas about this?
John

Title: Re: Exhaust pipes colouring
Post by: bsa-bill on 28.08. 2015 16:38

Mine are a beautiful straw gold colour, just how I like them, I'd leave well alone if that's the colour your getting, I'm guessing that although it disappears when it cools it will eventually stick.
Some folk run them deep blue, that I'm not happy with but it seems they keep going at that colour also

Title: Re: Exhaust pipes colouring
Post by: muskrat on 28.08. 2015 18:52

G'day John.
As you suspect both could be the reason. Spirited riding on a hot day can do it too. Leanish mixture or retarded timing. Wear at the points or carb slide/air leak. Are the pipes new? Could be thinner walled pipe or chrome.
I like to see a bit of colour for 6" or so. Pic 1 is good by me, pic 2 I'd be rectifying.
Cheers

Title: Re: Exhaust pipes colouring
Post by: a101960 on 28.08. 2015 19:35

Musky, the discolouration is no where near the colour depicted in of either of the pictures that you posted. There is absolutely no sign of bluing at all. The yellowing is very light and extends for about six inches, but like I said once the pipes cool down the yellowing completely vanishes. Pipes are 14 years old, and the chrome is still in perfect condition.
John

Title: Re: Exhaust pipes colouring
Post by: Greybeard on 28.08. 2015 21:17

Could they be Stainless pipes? SS tends to look yellower than chrome.

Title: Re: Exhaust pipes colouring
Post by: beezermacc on 28.08. 2015 22:23

Sounds like the bike is running about right. A slight discolouration is quite normal. Obviously, he yellowing is caused by the effect of heat on the chrome. The quality of chrome, thickness of metal and amount of heat are all variable but yellowing is nothing to worry about.

Title: Re: Exhaust pipes colouring
Post by: muskrat on 29.08. 2015 00:05

The pipes on my '51 are stainless. Been on there for 30 years with no discolouration. You know how hard I ride!! The pipes on the cafe are painted so no one see's how hard I ride. *evil*
Two ways to keep the pipes shiny and new.
1: Don't ride it. *roll*
2: Keep a soft tune.
As beezermac said, nothing to loose sleep over.
Cheers

Title: Re: Exhaust pipes colouring
Post by: Butch (cb) on 30.08. 2015 16:00

Pipes on mine are rusty and heat wrapped. Got a few stains coming through the wrapping now.