Starting problem By jaxrhapsody (Read 1,035 times)

[jaxrhapsody]

I don't know if its a cold issue, or a throttle issue; it started having starti g issues when the throttle got damaged from falling over, it was hard to start, and keep running. I replaced the throttle with a motorcyle throttle(for the metal housing), trimmed back the cable guide, so the the carb actually closes at reast, since scooters have less pull, and now it's even harder to start. It'll crank, and crank without blipping the throttle, and acts like the choke isn't working. Once it does start, it'll die if I don't keep blipping the throttle.

I want to just get another scooter throttle, and see if that fixes the problem. It's infuriating to no end, that it won't just start, and stay running like it did before it fell over. I've even sat for couple.of minutes with it running with it just over idle, and it still dies when it idles down. Maybe the carb needs adjusting.

[jct842]

Sounds like all you need is the idle adjust on the carb where the cable comes in to it. (not the pilot or air/fuel mix) That could be off too but get idle set first.

[Alleyoop]

Sounds like the throttle cable is allowing the butterfly to close all the way.
The throttle cable at the handlebar SHOULD have at least 1/8-1/4 free play before it actually pulls on the cable and opens the butterfly in the carb.

So do this On the Carb by the Throttle cable side you will see a SCREW with a spring under it Turn that clockwise about 1/8 and see if that keeps it idling without throttle. That screw is your IDLE SPEED SCREW all that does is open the butterfly just like the the throttle cable does when you twist it.
Alleyoop
This is a 24mm carb but all carbs have an IDLE SPEED SCREW to raise or lower the idle and what they do is just open the butterfly a litte more to allow more fuel to be sucked in.

[jaxrhapsody]

Oct 26, 2015 19:11:37 GMT -6 Alleyoop said:

Sounds like the throttle cable is allowing the butterfly to close all the way.
The throttle cable at the handlebar SHOULD have at least 1/8-1/4 free play before it actually pulls on the cable and opens the butterfly in the carb.

So do this On the Carb by the Throttle cable side you will see a SCREW with a spring under it Turn that clockwise about 1/8 and see if that keeps it idling without throttle. That screw is your IDLE SPEED SCREW all that does is open the butterfly just like the the throttle cable does when you twist it.
Alleyoop
This is a 24mm carb but all carbs have an IDLE SPEED SCREW to raise or lower the idle and what they do is just open the butterfly a litte more to allow more fuel to be sucked in.

Yeah, I was thinking that maybe the throttle is letting the carb close all the way, if I barely hold it, I can tell it's at idle rpm, there seems to be too much play. What happened to its orginal throttle, was it had fell over, and the top of the assembly had broken off, leaving it loose enough to slide off the bar, if I wasn't carefull. I bought a new one from the Motorcycle Superstore. I may wait until I can get a scooter throttle, that has proper rest, I think I trimmed to much of the cable guide, either that(since motorcycle grip options are pretty neat), or maybe stick a small spacer in there, but idle adjust will probably negate that.

Sorry I didn't post in this section, I didn't think it was specific enough.

[jaxrhapsody]

Okay, so I slowly turned the screw while letting it crank until it ran, and if the wheel started spinning, I backed it off little by little until it died, then adjusted the cable housing at the throttle, and redid step one. Turned it off, and restarted it. When it stared back up, the wheel spun, and I backed it off some more. Turned it off, and started it again, and now it idles without excessive rpms, or dying. Then I revved it, and it held rpm to spin the wheel, backed it off a little more down to idle, and- as I belive it always did; revved up some to spin the wheel, and then lowerd back to idle. I think I got it proper, now. Will come back after a drive.

If it wasn't for this site, I don't know what I would do with this thing. And since I had it open, I adjusted the seat latch, I kept having to bang it leftward to unstick, and open it.

[Alleyoop]

GOOD JOB, where there is a will there is a way. It should idle around 1500-1800 rpms. The Back wheel should start to turn around 2000+ rpms.
Alleyoop

[jaxrhapsody]

Oct 31, 2015 14:24:18 GMT -6 Alleyoop said:

GOOD JOB, where there is a will there is a way. It should idle around 1500-1800 rpms. The Back wheel should start to turn around 2000+ rpms.
Alleyoop

Thanks, it did stall twice, but once I get an actual scooter throttle(motorcycle one catches in the housing), I'll retune it. But its much better than it was, it idles, and has it's speed back.

[tvnacman]

Don't forget to let it run for 5 minutes to allow the auto choke to get you off fast idle. Then you can adjust your idle speed. If you think the cable is a problem disconnect it when you try to start it and set the idle.

I would check the valve lash if you have not done that yet. I can not get a stable a/f adjustment if the lash is off.

John

[jaxrhapsody]

Oct 31, 2015 17:35:32 GMT -6 tvnacman said:

Don't forget to let it run for 5 minutes to allow the auto choke to get you off fast idle. Then you can adjust your idle speed. If you think the cable is a problem disconnect it when you try to start it and set the idle.

I would check the valve lash if you have not done that yet. I can not get a stable a/f adjustment if the lash is off.

John

I'll make a not of that when I get a proper throttle. I had to mod the barrel holder, by trimming that back to the length of a scooter throttle barrel holder, and it catches in the casing, and there is still more freeplay than it should be, once I get a actual scooter throtle assembly, I can retune it, and it'll be like it was. It won't ever be correct with that motorcycle one.

[tvnacman]

a visual it best post a pic of what you have so we can see.

John

[jaxrhapsody]

Nov 1, 2015 6:48:05 GMT -6 tvnacman said:

a visual it best post a pic of what you have so we can see.

John

I can't do it. This damned bike had me in tears as I walked it the hour home tonight. I've adjusted it several times, it won't idle, it doesn't like to start, and tonight it about killed the battery to the point it hardly cranks, and the kickstart is useless unless combined with the starter. If it was a moped, I would've picked it up, and threw it across the street.

it has basically a dirtbik throttle on it from motercycle superstore. the throttle is not working. I bought a scooter throttle the otherday but it doesn't have a cable housing, and hadn't had time to put it on, and see if the other cable housing will work with it. I'm basicly sick of trying to fix it, and it not working.

I turn the screw, it's set too high, I slowly back it out so that it idles, and it dies, try it again and it's too high, then I get it just right, blip the throttle, and it revs up. turn the idle back down so it actually idles, turn it off, start it up, and it's up to high again. I'm sick of it, it just will not act right., and ai know the whole reason is that stupid dirtbike throttle, and now it will not even start, so even if I put the SCOOTER throttle on it, i can't get it to run to fix it. I hatd this bike. I wish I had just gotten anothe proper throtle to begin with.

sorry for the screwed up post, but I'm way to depressed, and angry to fix all the typos.

[tvnacman]

you need to do this next

let us know how things get better from there.

John

[Alleyoop]

Yes right now your problem is the throttle cable binding and hanging up and causing all your current high and low idles. Best is to just bite the bullet and get the right cable.
Alleyoop

[cyborg]

i second this approach,,,get the throttle mechanically correct then you can get the idle settled down and you can tune it from there