Starts up and Runs but will not accelerate By briankeith79 (Read 42,315 times)

[Alleyoop]

That is what I thought a bigger carb comes with bigger jets. When you said it runs only at 1.5 out with no air filter that is a give away to much fuel.

Take the air tube off the carb and start it and let it warm up say 5 minutes now turn the Air fuel ratio clockwise until it stops and see how it runs.
Alleyoop

[briankeith79]

Air tube off the carb? whats that? the air filter/airbox itself ?? or something else different ??

[briankeith79]

well I put the original carb back on the bike, I turned its fuel ratio fully clockwise until the screw stopped and removed the airbox/airfilter. I runs just fine that way, throttles up fast and sounds mean. However, soon as I attach the airbox/airfilter back onto the carb, it chokes out and dies still. Even with the original carb. Its getting plenty of air now and runs fine without an air filter, which is odd. Even though Id prefer an airfilter on the carb though lol. Here, I will make a video with my phone and post it on the site here in a few.

[Alleyoop]

Feb 13, 2014 22:15:37 GMT -6 briankeith79 said:

well I put the original carb back on the bike, I turned its fuel ratio fully clockwise until the screw stopped and removed the airbox/airfilter. I runs just fine that way, throttles up fast and sounds mean. However, soon as I attach the airbox/airfilter back onto the carb, it chokes out and dies still. Even with the original carb. Its getting plenty of air now and runs fine without an air filter, which is odd. Even though Id prefer an airfilter on the carb though lol. Here, I will make a video with my phone and post it on the site here in a few.

I figured as much, that is why I asked to turn the fuel ratio screw clockwise until it stopped. WHAT IT SHOULD HAVE DONE is KILL THE MOTOR for lack of fuel BUT IT DID NOT. So doesn't take a genius to say OH snit TO MUCH FUEL right? So because it is getting to much fuel it needs a lot more air OTHERWISE you flood the snit out of the plug, turns black, sooty and or wet from fuel.

So whatever PILOT JET is in those CARBS they are TO DAMN BIG PERIOD OR the motor is sucking in gas from one of the VACUUM HOSES.

SO to eliminate extra fuel being sucked in TAKE THE VACUUM hose AT THE INTAKE MANIFOLD where they connect and SEE if the VACUUM line or LINES are wet from fuel.

If they are DRY then the PILOT JET IS way to big. Do you know what size PILOT jet is in that carb?

Many folks put in big arse jets thinking that is going to give them more power and speed, but that is wrong what it does is flood out the poor little motor. A motor depending on the setup can only take so much fuel and air go beyond that point and they will not run or run like crap.
Alleyoop

[briankeith79]

just got done running the machine again, pulled off the vacumm line from the intake that opens the petcock on the tank, it was dry inside looking, no wetness. At least before I get a chance to change the pilot jets, do you think its a good idea to run the moped without an airfilter or airbox? It seems to run and accelorate just fine without one, which is crappy to imagine. At least until I can get some smaller jets. what do you think?

[Alleyoop]

Here is a way to determine if you have the right PILOT jet in. With everything on it Air Filter attached or AIR BOX with a clean filter the motor should KILL when you turn the fuel ratio screw clockwise cutting off the fuel when your about 1 turn before the fuel ratio stops. In that situation the motor should run good anywhere from 2-3 turns Counter Clockwise from the closed position. If your out 4 or more turns the PILOT JET in that case is to small so you go up to the NEXT SIZE only. Reason you do not want to be out 4 or more turns is the spring in there now does not have enough pressure on the screw to keep it from Vibrating loose and in many cases they fall out when your riding.
Alleyoop

[briankeith79]

ok I looked up my carb and did some reading, I even just got done pulling the carb back off the motor and took it appart on the bottom, opened the float area up and took both jets out. Apparently the IDLE JET is a 30 and the MAIN JET is a 91 .

[Alleyoop]

Well the 30 pilot jet is fine it has to be sucking in gas from the MAIN JET even though you are not opening the throttle. That 91 main jet is HUGE so leave the Pilot jet as is the 30 is good but the main jet get a #75 main jet. A #91 is for a 50cc with at least a 83cc BBK put in.
Alleyoop

[briankeith79]

hahaha jeezzus 91 too big? well damn, thats the way I got it when I bought it from www.partsforscooters.com website. I just bought, got it in mail and put it in lol. hmm ya Im checking out some areas now to buy a set of main jets to replace it with now. I was thinking about a 75 or 80 main jet, but I might try the 75 first like you said. Now when I replace that jet, would it be safe to put the airfilter back on it then? or try it first without the filter after I replace the jet? Normally I work on my car or I build computers, IT tech here, I can admit Im a noob too mopeds but I am more then willing to learn from what Im doing and I appriciate your help sir

[Alleyoop]

WOW!! you got it that way maybe they do that so you return and buy smaller jets(HAHA). The 50s usually come with a pilot jet 30-32 and a main jet from 69-75 so I am going with the bigger one for your stock motor(HAHA). A #80 is usually put in for a 72cc bbk.

But button it all up with air filter and everything on it, it should run good with everything buttoned up.

If by chance it has a little stumble in the mid-range we can lower the needle in the diaphgram.

Alleyoop

[briankeith79]

you know whats sad?? your probally right! lol they probally do sell it that way on purpose so you have to spend more money to get smaller jets, or a different air filter to help with ventilation issues. Go fig lol Well in mean time, Im done messing with the scooter for now till I can get those Jets ordered and here. I THANK YOU alot for your input and help, I will be back again to this site, I like it here! I will also recommend it too friends. Great site! After I get the jets installed and everything else, I'll tell ya the prognosis of what happenned is. thanks again

[briankeith79]

Well, I got my order today for some new Main Jet parts and a brand new air filter, I installed it all, put in the new jet.

At first it was hard to start it up, with the air filter on. I Turned out the fuel Mixture screw, until I could get it too Idle fine. = 2 and 1/2 times out is the final turn out. The Main jet in it now is a #75. So far, I can get it too start up and idle fine now, and it does.. Throttle up, However, When I pull the throttle, The first 1/4 throttle it kind of chokes itself a little bit, not too bad but it can die and I have to restart it. In the first 1/4 throttle when its trying to choke itself, I have to kind of, "Pump the throttle" pull and release it quickly a few times to get the engine speed up but once it gets past that point, I can full throttle it and the wheel spins nice and fast and it SCREAMS!!! lol

Any idea now why it might be choking itself out in the first 1/4 throttle? is the main jet too small now? maybe go too an #80 instead? not enough fuel in the first 1/4? The Air filter is aftermarket piece, its nice, works great.
Air Filter = www.partsforscooters.com/Air_filter_4-stroke_chrome

[Alleyoop]

The main jet has crap to do with the idle and really up to about 15mph on the 50s it is all PILOT JET.
Since you have it 2 1/2 try turn it clockwise 1/4 turn(LEANER) and see if that takes the stumble out. If it makes it worse then go Counter Clockwise Richer to 2 3/4. It is just a little off due to the Air Filter type you are almost there just a little tweak.
Alleyoop

[briankeith79]

You think if I go out too far on the Idle screw, would it just be better here soon to get a #35 or #38 Pilot jet? Cause I know from what I read on your earlier posts, If I get close to 4 out on the idle screw, I could take a chance and lose it down the road lol that would suck if it did lol.


Thanks Mr. Alleyoop! You deserve a freaking cookie and a beer! Your help has helped ALOT so far! People.. Listen to this man here!

[Alleyoop]

No, since your current Pilot is a 30 I would only recommend a #32, but I do not think to get the stumble out will take it past 3 turns out(which is good) anything between 2-3 turns out is right on. But if it does take past 3 turns out to take the stumble out then get a #32 and you should be PEACHY KEEN
Alleyoop