Soot/carbon black spraying exhaust tubes..

[Basri...]

There are little holes under the exhaust tubes, i think they were welded and repaired long ago but rotten again.

Above 3000 rpm, sprays soot on chain guard and swing arms..

I guess that means soot/carbon black built up in tubes. Before welding again and sealing these little holes, i'd like to ask;

Is it a sign of incorrect mixture or bad coils or else ?..
Also, when i put my palm at the exhaust otlets and pull the throttle, my palm turns to black, but, the smoke colour is normal..

Is this normal ?..

Is there a way to clean inside the tubes ?..

Many thanks in advance..

[Mustang]

running rich ............going to a hotter plug like an NGK DPR8EA-9 instead of DPR9EA-9 might be all you need .
But more than likely just patch the holes and all will be good .

[Basri...]

Yes, i have DPR9EA-9s.. Thank you Mustang.