Why is my carb (exterior) dirty?

[Lunatuck]

I'm sure this is not it cause how would it get there, but it looks like what you see when a tire is rubbing on something. Almost like a granular rubber.

Hmm. I am wearing through brake pads like crazy. Just installed 3rd set today in 200mi. Could be that. Its in the flow path from brake to carb. I’m starting to hate my rim brakes more every day.

 

[extremeodd]

If your chewing up brakes, that could easily be a culprit. Now that I think about it some more, that build up stopped on my bike once I swapped from a 27.5 to a 26in front because the 27 was rubbing my mz65 so that might have been rubber not exhaust soot I was seeing. *facepalm*

 

[Lunatuck]

Well, I replaced the brakes and exhaust yesterday. Also took the carb off and on while changing jets. Whatever happened, its not getting dirty anymore.

Fixed it without figuring it out.

 

[Frogslayer]

So it's Gary55 for the win?

 

[gary55]

So it's Gary55 for the win?

I guess we'll see. I ain't holding my breath.

 

[inspectorcritic]

Oil blow back you may need a reed doubt it will fit your TNT carb though, got a spare.

 

[Member 28982]

Gas /oil mix is sloppy. Its a dust magnet. Somtimes causes my carb to continually release fuel. Get some head gasket or carb cleaner. Spray about ever 30niles. Watch drip. Will eat paint on your enamel painted bike.

 

[CrazyDan]

Ignore the last 2 posts, gary55 was correct. The black crap was rubber, not oil/gas mix of any sort

 

[gary55]

Broken clocks, and blind squirrels are my kindred spirits.

 

[LewieBike]

I found that the Kehein clone carb on my Honda cub 125cc engine had one of the floatbowl screws loosen, and it was covered in sticky old gas gum. Just loose enough that a tiny amount of gas weeped out of the float bowl seam and capillary actioned all over the lower half of the intake manifold, carb and it's float bowl. Spray carb cleaner to the rescue, and afterwards always tighten your carb screws down with a proper Japanese Industrial Standard #2 screwdriver.