YY250T carburetor setting By bobf (Read 4,857 times)

[bobf]

OK, on my brand new YY250T,. Is this the best way to describe my scooter or is there a different preferred way?

Anyway, I have been letting it idle a bit since I got it running. Get it hot enough to cause the fan to cycle. The idle seems to be much too slow as the tach falls way down to almost zero. So I sit on the bike and hold it up more towards 1k.

I am wondering if in this case I should maybe make the air/gas mix a bit leaner. I have read that such a adjustment can be made but I am not sure if on the Helix/Honda engine. I am living at 6,300 feet and know that some cars I have had I needed to go in a change out the jets inside the carburetor. Of course now cars have injectors and computers to balance the air/fuel mix. They take all the fun out of owning a car.

I don't think just reving up the idle is really the problem here.

Any good photos and service tips on the carburators on my scooter.
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[Alleyoop]

Bobf,
Turn the IDLE SPEED screw Clockwise a little to bring your idle up. That is the Screw with the SPRING on it on the side of the Throttle Cable.
Alleyoop

[bobf]

Thanks Alleyoop. Next part of the problem is this. I went into the garage to see if I could do as you said but I can't find the carburetor. It appears to be somewhere between the battery and the hinge for the two leg stand. I got on the floor and looked up with a flashlight and that would be an impossible thing to do.

I looked at the tub under the seat but the only access from there is a estimated 4"X8" opening right over the left side of the motor. Can't see the carb from there either.

It appears that maybe the back part of that tub is separate from the front part, but I am not sure. Has anyone had the chance to see if it would come out. If it does, then I would have access to the engine and carburetor. Maybe if I was rich I would by a motorcycle lift stand and work from underneath, but I am not rich so I will attempt a tear down if it seems to be workable. Surprised I never thought of service panels while looking for a scooter.
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[Alleyoop]

Bobf,
The Carb will be about 8 inches from the front of the Valve Cover of your engine on the top of the engine. So getting a Lift is not going to help get to the Carb. You either get to it from the Sides or from the Top. The Entire Tub comes out But also your seat. Take a picture of what it looks like under the seat. The Carb will be toward the Front of the Tub or under the seat area.


Alleyoop

[Cruiser]

The larger access panel towards the front of the bucket which is secured by 2 screws is the cover for the battery and also gives you access to the carburetor. The idle speed adjustment is on the left side of the carb as you face the front of the scoot.

I have never removed the bucket for access to any part of my scoot. As alleyoop said, a lift would not give you access to the carb. Carb adjusts and valve adjusts can be done through access through the bucket once the seat is opened.

[Alleyoop]

It is Screw with a SPRING on it on the Side that your Throttle cable is. Just turn that Idle SPeed screw a little to bring your idle up it does not take much. Then you can bring it up to somewhere 1500-1800 rpms wherever it idles the smoothest and your Rear Tire just barely wants to turn.
Now you want to Adjust your IDLE AFTER the engine is Nice and Hot, give it at around 5 minutes so your ENRICHER (shuts off the extra fuel when cold).
Alleyoop

[bobf]

Thanks for the inputs. Leading me to what I was trying to avoid. Today I will go out and see what I can do and then report back. Maybe with photos if I remember to take the camera with me. Right now it is only 20F outside and about 30F inside the garage. I will wait a bit for the outside to warm up. With the garage doors open it will be quite cold now. In the afternoon the outside temp might go into the 40's F.

Any experience with the Haynes scooter books here? They have several but they also have one called Chinese Scooters for about $30. I am thinking of buying one but might change my mind if one of the others is suggested.
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[Alleyoop]

Bobf,
No, I have no experience with any of the books. I am mechanically inclined so I can get around without a book. I know engines and carbs and once you know what makes them tick they are pretty easy to work on yourself and saves you money on parts and labor. Some have bought those books so maybe they will chime in. Most scoots operate the same and have the same type of parts, just that some parts are a little different but they all do the same thing. On here we have PDFs about the parts on a Scoot and Engine and Electricals so people just get on here and go browse the generic books and look in the tech section.
Alleyoop

[bobf]

Thanks again Alleyoop. I finally found out what you were saying and I was not visualizing. I followed Cruisers idea and took the cover off the battery. There it was, the carburetor. Just enough to allow me to adjust the idle screw. It is now sitting at about 1800 on the tach. It wanders a slight bit over time but more or less 1800.

I had the battery cover off for a long time but I guess it never registered that the carb was right the. So after I finally covered the battery I just did not remember that thing. On the rear portion of the tub is the 4X8 opening that I mentioned above. I suppose that is for access to the spark plug. Anything more serious probably means I will need to take the side panels off and/or drop the motor assm for repairs. First I plan on getting some many many hours of good riding done.

This scooter is a big new thing for me. Most of my past mechanical experience has been on the big V8's of the 50's thru 80's. I have torn them down and rebuilt engines, swapped out and replaced carbs, pulled axles and even pulled the differential and reinstalled after a fix on it. But this little guy is all new to me. I apologize for my slowness in understanding what was written to me. But I am still a student and after many questions and answers I will learn.

I will watch for any and all hints and tips on this forum, but may decide to buy a book too.
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[Alleyoop]

Bobf,
FANTASTIC!! Now it is idleing at a good RPM, Now when you first start it cold the ENRICHER(CHOKE) will be Retracted allowing for more fuel for cold starts. So when you first start it say in the Morning your idle will be high probably over 2000 RPMS. But as the the ENRICHER HEATS up the Plunger will start to EXTEND to shut off the extra fuel in about 3-5 minutes time. And as your admireing it there listening and PUTTING ON YOUR HELMET the IDLE Should come down to where you set your IDLE in your case around 1800 rpms.
Ride Safe And be Alert for the crazy drivers.
Alleyoop

[Cruiser]

Good work, Bobf! The flat access panel with one screw that you mentioned earlier is for sparkplug and valve adjusting access. For routine maintenance, there is no reason to take off any body panels on this type of scoot. Access to the CVT is 2 bolts in the center of the CVT cover, the air filter is right above the CVT, and engine and transmission oil changes are straight forward. Access to rear taillights is through a door in the rear of the seat bucket. You already now where the battery, fuses, and carb is along with the radiator fill which is next to the carb. The radiator expansion tank is next to the gas cap. Replacing the fuel filter or fuel pump would require pulling some plastics below the foot rest area. Your engine is a Honda Helix CN250 clone and identical to the CfMoto 244cc. Just about any parts from these engines will fit your clone engine. The body is a Honda Reflex clone and the body panels can be interchanged with the Honda. Most people will use the Honda Helix manual found in our tech section for engine and transmission information.

The MC-54-250B and JCL250A are the same as the YY250T except for the engine layout. None of the Chinese vendors has put together a model specific manual for these scoots so they are truly generic.

[woofman]

i have the exact same issue... low idle rpms... will get out screwdriver this morning..

happy to report..... following  directions above.. i was able to change the idle RPMs to satisfaction.. now  idling at 1500 +/- tire in a very very slow rotation.. almost vibration speed... it sounds right... thanks very much!