Carb Tuning

[adark248]

OK! I GIVE UP! I've read and re-read, I've tried to filch as much information as I can from posts, but I just can't seem to get it. I'll gladly abandon my "Elite" status on the board in favor of "noob" if someone can explain just exactly how to tune a carb.

Every time I do it it seems to work out differently. I got it to perfect last night, I thought, but rode a little, put her on the stand and the wheel started spinning slowly. I don't want to retune it every time I ride and I think not having it right is murdering my MPG.

I started with the air screw at 1.5 turns out (84 Aero) and then turned the throttle stop until the wheel didn't want to spin anymore, then turned the air screw until the wheel started spinning a little, then backed it off until the wheel didn't spin anymore. Correct? What exactly does "highest idle" mean when the booklet refers to it? Can I tell that without using any kind of gauge, cause I don't have any and I don't have the money to get any.

[Kenny_McCormic]

As long as you can hold it with 1 finger its good.

[adark248]

Aha! Kenny to the rescue. Thanks. I guess I need not worry.

[evilone]

Yeah no worries, sounds normal to me

[Lunytune]

Forget the wheel and tune by ear. The engine will tell you what is the best performance. I generally screw out until it runs smooth, then back in until it cuts out, and then back off until it runs smooth again. STOP. That is the most efficient setting.
Then set RPM with the idle screw screw. If you had a tachometer, you could use that, but very few of us have a tach for one of these 2 smokers.

This is basic principle for all gas engines, 2 stroker, 4 stroker, scooter, lawnmower, auto/truck.

.

[Wheelman-111]

Greetings:

Exactly as LunyTunes suggests, with one pre-requisite:

If you set the throttle stop too high, you won't be able to tune the mixture. Start the scooter and ride it until it's completely warmed up - 10 minutes. Next set your throttle stop as slow as you can while keeping it running. It shouldn't be stalling, but idling as slow as possible. Now follow LT's suggestions to adjust the idle mixture.

Finally, reset to idle speed - the throttle stop - to a comfortable idle - Factory spec is 1800 RPM. What's important is that the idle RPM is well below the clutch engagement speed.

[Lunytune]

Exactly as LunyTunes suggests, with one pre-requisite:

If you set the throttle stop too high, you won't be able to tune the mixture.

Right on... When adjusting any carburetor (scooters are new to me, but principle is same) I generally start with idle. Then set air mixture. If I have to readjust the idle, I also readjust the air mixture, back and forth until it's running like I want.

You're sure taking me back to my old days. I had just about forgot how to work on carburetors since fuel injection took over. Still got my old 1982 hunting truck; which reminds me, I was going to overhaul the carburetor this summer.