Are one of these carburetors the answer to my problem?

[MN_Scoot]

I have been having recurring problems with my Agility 50 dyeing after about 45min of riding and often at WOT. I have recently cleaned with carb cleaner and saw light through the jet's pin holes. One of the last times it killed on me while riding, I coasted to the streetside and pulled the plug. As you can see, I have a lean condition.

I adjusted the air/fuel mix with a digital tach and it was optimized at almost 4 turns out which is quite a bit above the 2.5 recommended in the service manual. The mix screw turned that far out while still running lean means I need a larger main jet, right?

After all the hassle, I'm thinking of taking the easy way out and ordering one of the below-linked carbs. I've read so many horror stories on this forum of people ordering jets that don't fit the threads/jets that take forever to come/bad customer service.

That said, does anyone think one of the two following links are the easy answer to my problem? I've read here that 20mm carbs are plug and play, but even for GY6, there seem to be many variations.

Or do you recommend some other quick solution or link to a carb you recommend? I really need to use the scooter right away. Thanks in advance for any help!

This one says it's for big bore scooters, but maybe it would work for a stock scoot as well?
http://www.ebay.com/itm/True-20mm-Performance-Carburetor-139QMB-GY6-Scooter-Carb-KEIHIN-CVK-50cc-100cc-/171734637047?hash=item27fc2e99f7&vxp=mtr

The description for this one specifically states it's for a Kymco Agility, but doesn't list jet sizes:
http://www.monsterscooterparts.com/kymco-agility-50-19-mm-carburetor-with-electric-choke.html

[Chris0381]

Why dont you edit your profile and list all the mods and what you may have done to your scooter. Any changes you did from stock. Look at mine as an example. An example is when people come on asking for help and the members have no idea that they have cut the airbox wide open etc.

Also what type of scooter you have; you only mention agility 50.

See if we can start from there as somethings not right with your mixture. Why is it so far off form factory specs ?

Is your bike lean at idle, mid throttle, or full throttle? those have to be sorted out.

[MN_Scoot]

Why dont you edit your profile and list all the mods and what you may have done to your scooter. Any changes you did from stock. Look at mine as an example. An example is when people come on asking for help and the members have no idea that they have cut the airbox wide open etc.

Also what type of scooter you have; you only mention agility 50.

See if we can start from there as somethings not right with your mixture. Why is it so far off form factory specs ?

Is your bike lean at idle, mid throttle, or full throttle? those have to be sorted out.

Noted and changed. I assumed most people added that section when they had mods and not when they are essentially running stock as I am other than sliders.

I checked the plug after it dying at WOT. Doesn't seem to be a problem otherwise.

Not sure why it is off factory specs unless the dealer changed jets.

Thanks.

[BettinANDlosing]

This is incorrect, on the Agility 50 the mixture screw is a FUEL screw. More open, more fuel, more closed less fuel. If you have to have the mixture set at 4 turns out more than likely the idle jet is clogged. You need to blow through it and make sure a little air is getting through. The 8 holes on the bottom of the jet don't matter but the very tiny hole through it matters a LOT if its partially plugged it will do what yours is doing. Don't get the Made in China carb, the Kymco comes with a Japanese Keihin carb that is of vastly better quality. You need to clean it for it to run perfectly.

[MN_Scoot]

This is incorrect, on the Agility 50 the mixture screw is a FUEL screw. More open, more fuel, more closed less fuel. If you have to have the mixture set at 4 turns out more than likely the idle jet is clogged. You need to blow through it and make sure a little air is getting through. The 8 holes on the bottom of the jet don't matter but the very tiny hole through it matters a LOT if its partially plugged it will do what yours is doing. Don't get the Made in China carb, the Kymco comes with a Japanese Keihin carb that is of vastly better quality. You need to clean it for it to run perfectly.

Thanks a lot for the response. These problems actually developed after a thorough cleaning...soaked the jets, blew air through, etc. That's why I am getting a little defeated in constant troubleshooting and thinking of starting over. Maybe I messed something up when putting back together... I also remember the mix screw being four turns out BEFORE i cleaned it, too. Again makes me wonder if I need a larger main.

If I take it apart again and the jets are clean, is there a reliable place to maybe get a whole set of jets to try different sizes? Again, I've read so many horror stories here about ordering jets that it makes me wonder if it is rabbit hole I don't want to even get started with.

It's too bad you say those ebay carbs are inferior. Would really like an easy end to this drawn out mystery!

Thanks again for the input!

[Chris0381]

And thanks Bettin for a correction. I removed the post.

An option would be to take it back apart, see if the floatbowl is the correct height, and look at an assembly diagram for your carb and make sure all is 100%. I think there is a part that can be reversed yet the carb my still function somewhat and its to do with the float needle and the pin that runs thru it

I hear a lot of good things about keihin carbs and cant find them really on sale new or actual parts for them in the USA. At least not for our 50cc bikes.

[MN_Scoot]

And thanks Bettin for a correction. I removed the post.

An option would be to take it back apart, see if the floatbowl is the correct height, and look at an assembly diagram for your carb and make sure all is 100%. I think there is a part that can be reversed yet the carb my still function somewhat and its to do with the float needle and the pin that runs thru it

I hear a lot of good things about keihin carbs and cant find them really on sale new or actual parts for them in the USA. At least not for our 50cc bikes.

I actually already explored that possible issue already in a previous post. Apparently the manual's spec of 17mm float height is a typo, but consensus in the thread was that my float height was correct: http://www.kymcoforum.com/index.php?topic=11052.0

[Chris0381]

OK

But I ask what is there in a carb that wears out were you can't rebuild it. But then again where can you get a rebuild kit for your exact carb without buying a generic Chinese kit ?

Maybe a call to these guys http://www.carbparts.com/ they deal in Keihin carbs. Check out their jet section and tuning tips.

Are you 2 stroke or 4 stroke ?

Any possibility of air leaks etc ?

[tortoise]

have a lean condition

If you are using a clear in-line fuel filter, when the engine dies have you observed if there is fuel in the filter?  If there is, that may indicate an ignition related gremlin.

Keep in mind that the pilot/low-speed jet and throttle bore port fuel flow should be less of a factor at wider throttle openings.

To troubleshoot potential vacuum leaks, might try plugging the canister vacuum line, and apply a light smear of silicone grease (not RTV sealer) on the carb and intake manifold join surfaces.

[BettinANDlosing]

Aside from the jets clogging, and a possible tear in the diaphragm there is not really anything to wear out in these carbs and no "rebuild kit" really available, just individual parts to order.
http://www.harley-performance.com/images/pilot_jet1.jpg
That's what I would focus on is your pilot also called idle jet. If you want to order a new one here is a genuine Keihin #35 idle jet: http://www.jetsrus.com/a_jets_by_carburetor_type/jets_keihin_N424-21_slow_26-xxx.htm
You DONT need to mess with your jetting, other than the de-restricted main jet. This will just cause more problems. Your bike if everything is clean will run perfect with the #35 pilot. It is very rare that I actually have to replace anything inside these carbs, if you take a small piece of wire, like one strand from a brake cable you can send it through the idle jet and clear it totally, they can be partially plugged. Looking at the Agility 50 service manual the Mixture should be at 2 1/2 or right around there. Shouldn't be more than 3 or less than 2. Install a new idle jet and set the mixture to 2 1/2 and see how it runs.

[MN_Scoot]

Aside from the jets clogging, and a possible tear in the diaphragm there is not really anything to wear out in these carbs and no "rebuild kit" really available, just individual parts to order.
http://www.harley-performance.com/images/pilot_jet1.jpg
That's what I would focus on is your pilot also called idle jet. If you want to order a new one here is a genuine Keihin #35 idle jet: http://www.jetsrus.com/a_jets_by_carburetor_type/jets_keihin_N424-21_slow_26-xxx.htm
You DONT need to mess with your jetting, other than the de-restricted main jet. This will just cause more problems. Your bike if everything is clean will run perfect with the #35 pilot. It is very rare that I actually have to replace anything inside these carbs, if you take a small piece of wire, like one strand from a brake cable you can send it through the idle jet and clear it totally, they can be partially plugged. Looking at the Agility 50 service manual the Mixture should be at 2 1/2 or right around there. Shouldn't be more than 3 or less than 2. Install a new idle jet and set the mixture to 2 1/2 and see how it runs.

Thanks for the reply. I just pulled the carb again. I pulled the idle jet and let it air dry to be sure fuel wasn't making it look plugged before checking and when dry, I could see crisp circles of light through every hole including the main center hole.

I took the attached photo. It's worn, but it appears I have a 35 idle? My main jet is an 80, so it appears the dealer never changed that when they derestricted. I've read in these forums that others jump up to an 82-85 main when derestricting. Could that be part of the problem? I didn't have these WOT lean stall-outs before I first cleaned the carb. I'm running out of things to check. I replaced the intake gasket, new stock air filter, all new fuel lines, new fuel filter, new petcock. I've practically built a new stock scooter piece by piece and am about ready to bash my head against a wall...hence wondering if an all new carb might just be the last thing left.

Let me know if any of the above info changes anything.

Thanks again. Excuse me while I go cry over a beer. 

[MN_Scoot]

...another piece that may help solve he puzzle. The scoot seems to be mostly fine at slow to mid-speeds, so I'm guessing the pilot jet isn't the problem? When it stalls, it's usually after several minutes of wide open throttle. It won't start again until I hold the throttle wide open for a while while turning the ignition. Perhaps this means the bowl is empty?

If it's not an empty bowl, could re white plug mean it is overheating from the lean condition? Would that cause the acooter to die at higher speeds?

Thanks again. Really appreciate everyone's input! I've been trying to solve this for a year now.

[BettinANDlosing]

Sounds like vapor lock, look up my emission removal thread and follow it.