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Post by princessdawn982 on Jun 27, 2012 14:30:16 GMT -5
2009 Keeway Hurricane 50cc. Replaced carb and changed to manual petcock valve. Spark plug good. Air filter clean. Compression good.
Been trying to adjust the carb air screw and idle screw. Starts up fine. But bogs down and almost stalls at high end power. Doesnt do it on center stand. But when I take it off and go to ride,I can't go anywhere. I spent 2-3 days adjusting the air screw and idle screw and it doesnt help. Any advice is needed. Thank you.
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Post by wile on Jun 27, 2012 14:38:33 GMT -5
So your carb has an AIR RATIO screw on the RIGHT OF CENTER? If so they are very picky turn it very litte CLOCKWISE like 1/16 at a time, also check for any air leaks make sure the clamps holding the carb are nice and tight and no extra air is getting in.
Wile
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Post by princessdawn982 on Jun 27, 2012 15:46:06 GMT -5
The clamps are fine. And yes the air screw is on the right.
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Post by wile on Jun 27, 2012 16:44:37 GMT -5
Ok, to find out if it is running LEAN OR RICH at higher rpms do this:
When it starts to Stumble BACK OFF THE THROTTLE about 1/4 of an INCH AND HOLD IT THERE.
A. If the motor speeds up it is LEAN
B. If the motor stumbles and or hesitate and Settle down your RICH.
That will tell you which way to turn the AIR RATIO screw.
Wile
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Post by princessdawn982 on Jun 27, 2012 22:58:39 GMT -5
its lean. Whats that mean.
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Post by wile on Jun 27, 2012 23:12:59 GMT -5
That means you need a little more fuel, so turn the AIR RATIO SCREW CLOCKWISE try 1/8 turn and see how that effects it if still Lean give it another 1/8 turn etc..
Wile
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Post by ltdhpp on Jun 28, 2012 0:18:36 GMT -5
Doesn't that screw only affect the idle fuel circuit?
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Post by wile on Jun 28, 2012 0:28:52 GMT -5
no
wile
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Post by wile on Jun 28, 2012 0:31:14 GMT -5
Don't believe what MOST people say that the Fuel Ratio OR Air Ratio screw mixture ONLY is for idle. They don't really know how a Carb works, they think they do and read sh!t idiots put up.
Wile
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Post by ltdhpp on Jun 28, 2012 12:01:52 GMT -5
Interesting... I'll start playing with that too then as I experiment to try to figure out my issues.
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Post by Blueboy5000 on Jul 3, 2012 14:42:56 GMT -5
Agreed. The idle screw is the screw that acts as a stop for the throttle. It's on the other side of the carb,and on top whereas the a/f is clearly on the bottom left side.
The a/f screw controls exactly what it sounds like it does, the mixture of air and fuel.
I think adjustable needles screw with people, they seem to grasp why they are adjustable, and then figure they can be used to accurately adjust your mixture, which they do not. The needle actually makes rather broad fuel mixture adjustments, and should not need adjusting unless your jets have been changed.
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Post by Blueboy5000 on Jul 3, 2012 14:45:57 GMT -5
Or on my 2t Kymco the mixture screw is on the right of center as well. It is clearly not the idle screw as that is also on the throttle cable side just like a gy6
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Post by wile on Jul 3, 2012 15:03:21 GMT -5
Most 2 stroke carbs that have the Throttle cable going into the top of the carb that directly LIFT the Slide up to pull the needle out of the Main jet have the IDLE screw on the Left side in the center. That IDLE screw turning it Clockwise IN lifts the Slide up and raises the IDLE Counter clockwise OUT drops the SLide and lowers the IDLE.
Wile
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Post by teddy554 on Jul 3, 2012 15:14:55 GMT -5
I had a vento zip i bought for 200 dollars that did the same thing what i did was switch the carb and it runs like a champ. I ask for help on here and tired everything everyone said but wouldnt help i had to switch the carb bad thing was it look fine and i could never figure out what was wrong with it. this is link to my video holding it wide open and would just die and there is one of fuel petcock working s1111.photobucket.com/albums/h479/teddyc554/?action=view¤t=VID_20120112_171030.mp4 |
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Post by gregw on Jul 7, 2012 7:46:05 GMT -5
Main jet=3/4-full throttle. needle jet=1/4-3/4 throttle. Air adjustment screw= idle-1/4 throttle. The air adjustment screw can effect carburation up to 1/2 throttle, but has zero effect on WOT (intake air passes through the path of least resistance which is certainly not a little pilot air hole next to the wide open throttle ventury where your main jet selection is influenced). Always tune your scoot from the top down. Select the main jet to run at WOT best/ proper burn color on the plug, then adjust/select the needle jet, then fiddle with the air (idle mixture) screw. Never the other way around (unless you don't want your scoot to run well). Good luck!
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Post by gregw on Jul 7, 2012 7:51:51 GMT -5
Any change to the main jet effects all other perameters of the carburetors jetting (lesser so at idle), but, changing/adjusting the air mixture screw has zero effect on how well it runs at WOT, which is exactly why jetting selection starts at the the main jet.
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Post by dude on Jul 7, 2012 8:09:16 GMT -5
Did you check the size of the main jet of the old and the new carb? The new carb may have a different size jets.
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Post by geo49 on Jul 12, 2012 9:08:46 GMT -5
I had the same problem when I switched to a larger main jet.
On the center stand it was fine but every time I would try to ride it would bog down.
I had to replace the stock air box with a free flowing open element air filter to get enough air to make it run properly under a load.
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Post by wile on Jul 12, 2012 11:23:07 GMT -5
Like I said do not believe that the Fuel Ratio Mixture DOES NOT EFFECT WOT, there is ALWAYS fuel being drawn out of the 4 Pilot jet holes by the butterfly even at WOT. Of course it is less than at idle and lower rpms BUT fuel is always being sucked out of those holes as well.
If it is running a little lean at WOT NOT enough that it requires a lot of fuel and you are getting BURP sounds at higher RPMS all it needs is about 1/4- 1/2 turn of the Fuel Ratio and WHOLA no more BURPS.
Wile
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