black smoke at high rpm

[chemomche]

i have 750 kat pre98
everything stock, only put some holes on the ends of the exaust pipes to make the bike louder
now at neutral when hit the 12000(or the engine power cutter or whatever its called) there is black smoke
well it mean s rich fuel mixture, but the spark plugs are not black but brawn-white which colour i think the should be
is this black smoke a problem???
the bike runs well, should i be worried?

[Kattie]

Not so sure its a bad thing...ive seen alot of cars bikes ect. puff black smoke when your on the rev limiter...but im kind of curious also so we will see what some of these other guys say about it.

[Kreylyn]

Rev limiter kicking in means it's killing spark to some of the cylinders. No spark, no combustion. No combustion means unburnt fuel goes out the exhaust enriching it. Rich exhaust means black smoke most of the time.

If it isn't smoking before the rev limiter kicks in... you have no concerns.

Krey

[nismoz]

as stated,revlimiter kills the ignition coils sending unburnt fuel causing this,my sugest would be stay away from the limiter(yeah it sounds good but it means STOP) most cars don't produce the smoke cause they pulse the injectors instead of the coils.

[SouthyD]

Yeah as above, wouldn't be worried about the black smoke...
I'd be a lot more worried about the the effects of ridin the rev limiter in neutral

[chemomche]

Yeah as above, wouldn't be worried about the black smoke...
I'd be a lot more worried about the the effects of ridin the rev limiter in neutral

i took yur advise, now i do it on 1st and 2nd gear when drifting

[GSXF 600 Guy]

As stated many times, the rev limiter is good for sound affects, but not good for the motor. It having a black cloud at the limiter happens all the time. Hitting 12,000 RPM (in neutral) and keeping it there even for a few seconds is putting stress on everything (rings, pistons, valves, valve seals ect..). Plus the Kats are not liquid cooled bikes. You can cause the motor to start warping and blowing gaskets. Why try killing the Kat? Doing it while moving (in any gear) still isn't good. plus people think you dont know how to shift. 6th gear, I'd say everyones intitled to find the top speed on their bike at least a few times. Yeah, ok bikes can take ALOT more strain then a cage but over doing it just for the sound? Just some food for thought, not a good idea to do it!

[ATOMonkey]

I don't know how "bad" it is for the motor. Speaking from a strictly engineering stand point, the only thing detrimental to bouncing the engine off the rev limiter is the stress that accompanies those kinds of engine speeds.

Mostly to rods, wrist pins, springs and valves. All of those things are cycle dependant though, which means that just because it worked once or twice or even a hundred times doesn't mean it will work the next time, or it may work forever. I don't know what kind of margin suzuki built into their HCF limits on components.

[GSXF 600 Guy]

I don't know how "bad" it is for the motor. Speaking from a strictly engineering stand point, the only thing detrimental to bouncing the engine off the rev limiter is the stress that accompanies those kinds of engine speeds.

Mostly to rods, wrist pins, springs and valves. All of those things are cycle dependant though, which means that just because it worked once or twice or even a hundred times doesn't mean it will work the next time, or it may work forever. I don't know what kind of margin suzuki built into their HCF limits on components.

But if it is neutral its not moving, not getting airflow past the motor their is no real cooling of the motor. Which means, motor can warp, head can warp and other parts start breaking down due to overheating. Ant thats a Bad thing when any motor overheats. Am i right?