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Post by als01seville on Apr 3, 2010 20:45:26 GMT -5
Here's a simple and quick way to test if you are running Lean or Rich at Just about any Throttle position,WOT, Low Speed, Mid Range etc..
When you notice a Stumble, Back off the throttle a little 1/8-1/4:
1. If it surges ahead your Lean
2. If it stumbles and recovers your Rich
Now depending on where in the Throttle position this happens Different settings have to be done:
1. If it stumbles as your starting off - Adjust your Air/Fuel Mixture
2. If it stumbles in the mid range - Adjust your Needle
3. If it stumbles at WOT - It could be your Air/Fuel Mixture or you may have to Re-Jet.
Alleyoop
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Post by Florida Chameleon on Apr 4, 2010 13:25:03 GMT -5
That's EXACTLY what I've been trying to find  Thanks also! +1 |
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Post by shutupandheadbang on May 24, 2010 0:42:15 GMT -5
Ok, so I have a question. I know where the screw is on the carb to adjust the mixture, but I don't know how to guage how much to turn, nor in which direction. Also, should I be adjusting the idler screw with the fuel screw? Do you have anything you could post to help with this?
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Post by greezygiger on May 24, 2010 11:44:03 GMT -5
when adjusting carb screws think of the screw as a clock and adjust 1 hour at a time small amounts i believe are best and im sure the other dawgs will agree. as far as the adjusting screws i set my idle screw high when i was first tunning my carb on my 4stroke tank scoot so it wouldnt die if i had the mixture off. but i was riding it around too and would stop to adjust the fuel screw 1hr at a time. i took me about an hour to get it right after i did all my mods to my lil 50. hope this heps you
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Post by als01seville on May 24, 2010 12:55:55 GMT -5
ADJUSTING YOUR AIR/FUEL MIXTURE:
YOU WANT THE HIGHEST RPMS OUT OF THE AIR/FUEL MIXTURE SCREW:
This is for you common CV Carbs that have the Air Fuel Mixture Screw Near the INTAKE goint to the Engine. Other Carbs may have the Air/Fuel Mixture On the Air Filter Side with those JUST CHANGE the WORDS "CLOCKWISE to COUNTER CLOCKWISE" and "COUNTER CLOCKWISE to CLOCKWISE" other than that same thing applies.
Before you start it Turn the Air/Fuel Mixture Screw CLOCKWISE UNTIL IT STOPS do not tighten it just until it stops BUT COUNT how many TURNS IT TOOK TO CLOSE it. Then Turn it COUNTER CLOCKWISE the same amount of turns back to where it was.
Then Start your scoot and Get The Engine Nice and Hot about 10 minutes so that the Enricher is no longer Allowing Extra Fuel to come in. Then do the following to fine tune the Air/Fuel Ratio:
RICHEN THE AIR/FUEL MIXTURE:
1. Turn the Air/Fuel Mixture COUNTER CLOCKWISE 1/4 turn and wait 10-15 seconds to let the engine catch up with the new setting.
a. If the RPMS go up REPEAT 1 UNTIL the RPMS GO DOWN OR NO CHANGE.
b. Then TURN the Air/Fuel Mixture 1/8 CLOCKWISE and that should be your highest Air/Fuel Mixture setting.
"""If on the FIRST 1/4 TURN from the STARTING Position IN #1 ABOVE the RPMS GO DOWN OR NO CHANGE, turn the Air/Fuel Mixture Back the 1/4 turn to the Starting position and wait 10-15 seconds until the engine catchs up and go to #2"""
LEAN THE AIR/FUEL MIXTURE:
2. Turn the Air/Fuel Mixture CLOCKWISE 1/4 turn and wait 10-15 seconds to let the engine catch up with the new setting.
a. If the RPMS go up REPEAT 2 UNTIL the RPMS GO DOWN or NO CHANGE.
b. Then TURN the Air/Fuel Mixture 1/8 COUNTER CLOCKWISE and that should be your highest Air/Fuel Mixture setting.
IDLE SPEED SCREW:
3. If after adjusting your Air/Fuel Mixture your idle is to fast Turn the IDLE SPEED SCREW COUNTER CLOCKWISE until your Rear Wheel JUST Barely wants to Turn or around 1500-1800 rpms.
4. If 1 or 2 above DOES NOT produce any RPM Change you most likely have a CLOGGED PILOT JET "OR" you did not get the ENGINE HOT ENOUGH and you were working against the ENRICHER which has not yet closed off the extra fuel. If the engine was nice and hot running for about 10 minutes and the Enricher was off then its time to take off the Carb and Clean out the Jets and all the Carb Passages.
If adjusted correctly you should be able to give the Throttle a QUICK half turn and the Engine should REV UP with no bogging hesitation and get a nice VROOOOOOOOOOOM. The Rpms should come down nice and settle at the Rpms you set your Idle to.
Alleyoop
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Post by shutupandheadbang on Jun 7, 2010 23:14:59 GMT -5
Sweet Deal guys, thanks. I'll try that tomorrow. Sorry it's taken so long to reply, but have had a busy schedule at work, not much time to tinker. I'll let ya know how it goes.
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Post by irridum on Aug 24, 2010 15:00:18 GMT -5
And if the above post's don't help the problem curb the urge to get the sledge hammer out of the tool box & just read the rest of the forum. It is amazing how the simplest things can cause a hiccup on the Chinese scoots.
Get the urge at times to konk myself with the hammer when I spend an hour overlooking something right under my nose.
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Post by scootercapecod on Sept 9, 2010 19:35:07 GMT -5
Don't feel bad...I've done that more than once! As for the adjustments etc, you should also check out Big Guy's carb cleaning 101 video.
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Post by 50seesee on May 17, 2011 10:23:18 GMT -5
Sweet, this helped me out a TON. I don't have any throttle problems anywhere in the RPM range, but I have a visible amount of smoke coming from the exhaust and I want the engine to respond (coming off idle) a little bit faster. Would I be correct to guess that I'm close to the ideal mix, but I'm on the rich side? (Before messing with the carb there was no visible smoke at idle.)
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Thanks also! +1 
