Sputter and plug fouling

[johnny340]

I have an '06 BWS with Stage 6 70cc kit on it.
Chinese fake dellorto PHBG21mm carb with:
82 Main
32 Pilot
60 starter
Clip on 2nd down

Runs great on top but not great off idle.
Eventually fouls the plug. Went to BR8HS.
It sputters as seen in this video I'll try to upload.

[johnny340]

Can't see how to add the video..


W16 needle
Mixture 1.5 T out

[90GTVert]

Video has to be hosted elsewhere and linked. If it's on YouTube, you can use video tags.
49ccscoot.proboards.com/post/7985


If you try much tuning and it won't respond, I'd suggest taking the carb apart and doing a thorough cleaning and inspection. A good idea on any carb, but possibly more necessary on Chinese clone carbs.

If it's sputtering at very low throttle, but still moving OK, I don't worry about it. I like mine to sputter at low throttle positions around town. Most of the time they have to stay a bit rich down low because with big bore kits we can go pretty fast and get RPM up even with low throttle openings. If it's sputtering to the point that rideability sucks (surging, bucking, won't go...), then it's not normal.

[johnny340]

The sputtering is happening at higher throttle settings. I went to a hotter plug and it helped a bit but it's still not right. The rpm also hangs when stopping and takes a while to settle to an idle. The carb is brand new.