carburetor setting

[csor.zola]

Hi there,

I have a question about the carb. According the manual the pilot screw should be open by 3-3,5 turn. But....my problem is when I accalerate from nil SOMETIMES (not all the time) my bike hesitate a bit. Crackling for a half of a second and then rides smoothly. I have already cleaned the carb. It has 96 main jet and 104 the other jet. (I don't know what is called). The manual says it should be 95 and 105. But this is how I got this scooter. I am the 2nd owner and was nearly brand new. 2013 model with 3000 miles. Can anyone help how to solve this problem?

[BettinANDlosing]

Try this, warm the bike up by actually driving for about ten minutes. Then adjust your idle so it is slightly higher than normal then 1\4 turn at a time screw in your fuel mixture screw until you find the highest idle. Chances are you're bike will be happy around 2-1/2 turns out.

[csor.zola]

So.....I had a chance to try to solve this problem. And the result is....well...you tell me some conclusion. I played with the pilot screw and what I can say is the more open the pilot screw the worse the problem is.but even if I close it COMPLETLEY somewhat the problem still persists. Most of the time accelerate  without hesitation but 1 out of 3 it hasitates. But obviously in this position my spark plug quite black.
One time I opened the pilot screw as far as I could and when I took it for a test drive I lost it. It fell out and the rev went up. I was very far from home I had to drive it back. So I lower the idle speed and.....you won't believe this. The problem completely disappeared. It was smooth and fast from nil up to the end.
I can think of only one think. It must be with the valves. Or any idea???
I had a spare pilot screw so I put it back and opened it with 1 turn. Can I damaged the engine if I am running with too rich mixture??

[BettinANDlosing]

Ok you have it totally backwards.... The mixture screw is a FUEL screw on your scooter, meaning the more close the leaner the scooter is. I'd check your air filter, black plug means rich. Possibly the previous owner put the wrong idle jet in? Also when you lost your mixture screw did you check that the little shopping, washer, abs oring didn't get lost? You should never be out more than about 3-1\2 turns.

[csor.zola]

Aaaaa.. I thought if I closed the screw it gets less air. I have just replaced the air filter. But I gonna remove it to see. Maybe you're right.
The spring and everything is in there. I didn't loose them.
But I am still thinking about the valves.

[BettinANDlosing]

They may be off, but don't make a scooter act rich. That's a carb issue.

[csor.zola]

I took apart the airbox and tried without it. I haven't noticed the problem. So it means definitely it needs more air.  So, I have to change either the airbox to a tuning airbox or change the pilot jet to a smaller one.

[BettinANDlosing]

Don't screw with the airbox until you know what's wrong inside the carb.

[csor.zola]

Gooood news. The hesitation problem is solved. And thank you for your help. It helped me a lot. Basically, the problem was with the idle jet. I had a spare one. Size 32. Originally it was 36 in it. According to the manual should be 35 but who cares. I mean as long as it works with 32 that's fine for me.
Well...I haven't tested it in a long distance only in a carpark. But at least now I know what to do if...if I will have to correct it.
Thanks again.
Later on I will check the spark plug. If it's still blackish I will change the main jet as well.

So, the conclusion and the msssage to everyone who has a hasitating bike during acceleration. Guys the problem might be with idle jet.

[BettinANDlosing]

What's your elevation where you live? 35# works great here at sea level.

[csor.zola]

I live in the top of Himalayas

[csor.zola]

Actually in london

[bluescoot125]

Can't seem to find the fuel screw on mine. Someone said its on left side of carb but I can't find it without taking the whole bike apart to get a good look. (Agility 125)