discolour to down pipes

[bunnysZ]

put a new 4-1 exhaust on about 2 months ago and nos 2&4 downpipes discolour at the top as normal but nos 1&3 are staying chrome,have had a few probs with blocked jets and rough running which are sorted out now ,but exhaust downpipes are still the same, why would this be , is there a underlying problem i am not aware of. all 4 pipes are hot and all cylinders are firing. any advice appreciated.

[Mark O C]

It sounds like 2&4 are running hotter, or maybe the timing on those two is slightly different causing it to run cooler on 1&3. I personally would look at the mixture on 1&3 and go from there.

[debben1]

When a chrome pipe is new you can prevent discolouring by spring the inside of the pipe black, your pipe discoloured on 2 pipes when it was new but as 2 cylinders may have been running rich these would have sooted up and not discouloured, it could be the bike is running fine now but the sooted up pipes act as painted black pipes to prevent the discolouring , Steve

(Edited by debben1 at 4:32 pm on May 15, 2006)

[ollie]

nice one steve ,learnt summat new today ,thanks

[rickman CRR]

Its not the timing as this would surely pair up the 1-4 and 2-3 pipes if it was off? Previous issue with the fuel mix is probably to blame for the "tint".

[Steve R]

Steve ,
I never heard that one before and i am just about to put a new vance and hines on.
what do you spray the inside with just ordinary VHT paint??

[Big John]

Heard of people putting 2 stroke oil down new exhaust pipes to prevent rusting from the inside maybe that would also prevent the pipes discolouring.

[bunnysZ]

i thought it might still be incorrect mixture , as get slight popping when bike warmed up and de-accelerating. (also have dyno electronic ing) have cleaned discolour off 2&3 and it returns just to those two,so think i will take it somewhere to tune it correctly , handy tip about spraying pipes though ...thanx

[Pigford]

Pipes will ofter end up slightly different colours... especially on 4's. Pots 2&3 will get hotter being in middle anyhow. You'll have a tough job getting all balance to run exactly the same..... Even better... spray outside black, then you won't see the difference!

[debben1]

Hello Steve R, Yes, we used to spray the inside of customers Vance and Hines before fitting them so as to prevent the discolouring, well it works for a while, depends on how the customer rides, those that where steady riders with a priority on looks would stay looking new, others that lets say ride enthusiasticly (read thrashed/ragged/raced/cained) will still end up with discolouring unless the bike is set up on the rich side, Mine have a luvly shade of purple into blue and then gold :)

[debben1]

Hello Bunnyz, have you checked valve clearances recently ?