Black Smoke

[mark6453]

Hey my bike started blowing black smoke 2day not heaps but when i rev you can see it just wondering if any one knew wat was goin on cheers, Mark

 

[cry1100]

this is normal with chinese when their cold or are on choke pobaly nothing to worrie about

 

[Maylands Performance]

Hi mark6453. [Black Smoke=Fuel=Running too rich !] [Blue Smoke=Oil=Burning oil not good !]

 

[cry1100]

that is the fuel mixtures problems,maybe mix scale too strong

 

[Pittin]

i thoguth black was when your rings are ******??

oh wiat thats white smoke

 

[mark6453]

so where is the mixture screw on the carby

 

[Trashthumpy]

it should be underneath on the left hand side kinds recese into the side of the bowl.

 

[Power Man]

black smoke = un burnt fuel,

this is why you see modified turbo'd cars blow puffs of black smoke at high rmp and at cold start up.
this is to compinsate for the extra air from the turbo and make it a little richer for a better burn.

yeh just adjust ya fuel air mixture.

1. let the bike run to operation temp
2. get that screwdeiver out and litsen carefuly to when the engine revs a little higher meaning that the right mixture gives a better burn = more power.

OR

adjust it out to let more air than fuel into the mixture and rev ya bike and see if that black smoke is still there. if not tinker around with it till you get the desired result

3. thrash it

 

[mark6453]

sweet thnx

 

[cass38a]

The mixture screw on these carbys only affects the very low throttle openings (idle until one quarter throttle) so if its blowing black smoke at less than one quarter throttle then its your mixture screw. The mixture screw wont do a thing if its at half to full throttle.

 

[mark6453]

would the mixture screw help because when i put the throttle on fast it revs really low and then shoots up i mean the revs

 

[cass38a]

At what throttle position is it blowing black smoke. Idle, mid throttle or full throttle? or is it blowing black smoke all the time? Is your air filter clean? If your air filter hasn't been cleand then I would clean it first and see if it helps.

 

[Mack]

Without knowing your setup, generally most of the carbs used are running too big a pilot jet and too small a main jet. Rich on bottom, lean on top. This is where this bogging on a fast throttle opening is coming from that nearly everyone complains about. It also is probably responsible for your little puff of black smoke.

 

[mark6453]

so mack how do i fix it

 

[Mack]

Well a good place to start, is look at what jetting guys are running in the same carby as yours. Whatever that is...

 

[mark6453]

ok thnx ill have a look around

 

[mark6453]

ok thnx ill have a look around

 

[Mack]

If your willing to give us a hint at what bike and/or carby were dealing with here...we can be much more helpful...

 

[mark6453]

hey haha sorry bout that yer its keh hin or somethin think its 21mm

 

[Mack]

Well if you wanted to really attempt it you would need to pull it off, identify it for sure, check current jet sizes, buy some more, try them out.