Air Screw placement

N

Novice

New Member
Hello.
I have recently put a Chinese engine on my bike.
It has been a great experience and I have had lots of problems owing to my own ignorance.

Now everything works well except my spark plug being black and wet giving not enough power to the engine. I was hoping someone could tell me where the Air Screw is placed, as I have been told that this should be adjusted so that the engine will be more lean.
Any ideas?
Thanks.
 
Odds are you've the older style carburetor, in which case you haven't got an air/fuel set screw to adjust - if there's only one small, brass set screw on the side then it's indeed the far more common carb & that's just the idle set screw.

Never fear, you can still adjust your fuel/air mix - ya just need to take the top of the carby off and change the needle clip placement to a different slot, up for leaner (what ya want as yer runnin' rich) & down for richer. Yer after a nice coffee/tan plug color - white is too lean and can result in damage.

Here's a few pics;


Just be careful when reassembling as there's a tiny pin that needs to align with the cable slot in the slide, it's quite easy to sheer it off if you're not aware of it;

 
Thanks BarelyAWake, I did what you said and felt I have got a new bike today.
The needle clip was in the middle of 5 tracks and I placed it one up.
My engine with 80cc and 56 teeth sprocket is best tested going up hill and what a difference.

Since I got such a good response I wonder if someone would recommend a good spark plug. The one I have is probably good enough for some time but it would be nice to know which spark plug to replace it with.
Again, thanks a lot.
 
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Most builders rely on the NGK plug, number B6HS. I use them but I've had very good luck with the Champion 811/ L82C plug. I don't know about the availability of either of these plugs in Norway but they can be ordered from the U.S, I'm sure. Check with the sponsors found on this forum.
Tom
 
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