Carbon build up in exhaust

[Johnon]

I have a black widow 4 into 1.
I fitted it probably about 1500 miles ago aprox.The first thing I noticed was when cold starting.The bike went up to 2500 revs before coming down to 1100 where as with the 4 into 2 it cold started at about 2000 before dropping.Not a big prob just an observation.
The 2nd prob is black carbon deposits in end can and the poor indicator at the end of the can needs cleaning after every ride.Is there a fix for this and what is the likely cause or is it normal.Engine fine otherwise

[seth]

It shouldn't be like that
Has it ever had a power commander and been remapped as aftermarket exhausts can really Ness up the fueling.

[Phill P]

Some sooty carbon is normal, it's a basic fuel injection system from 2000's, not a modern super clean engine, you can literally chew on the fumes out of the exhaust

[KiwiCol]

The cold start high revs is normal, it's supposed to do that.  Going to 2500 instead of 2000 could be because of the new end can or because of a different temp or a mix of both.
The black sooty deposits in your end can is also normal AFAIK.  My end can has a polished SS end bit & that gets black with exhaust on the inside, I used to clean it when I first put it on, but don't now. It's fine & the bike runs as it should. 

Nowt to be concerned with there, unless your soot is thick & flaking off.

[Eric GSX1400K3]

Just watch your fuel consumption as an indicator. Some soot is normal with aftermarket systems, but excessive soot and high fuel burn indicates a fuelling problem.

I have an Akrapovic full 4-1 system and the carbon end piece has always been reasonably clean. Had a bad batch of fuel and now lots of soot and very high fuel burn (i.e. Last rum into town and back, about 105km round trip and it burned through 2 bars on the display,ran like a pig the whole time.)

Cleaned out the fuel system, including tank, hp pump teabag and bypass filter, new lp filter and even removed the injectors and fuel rail.I have new injectors coming, hope that resolves it.

Hope yours is not as bad as mine, but a check of the system would be a good start.