so close...someone help!!!

Vespalad /

Sep 16, 2001 05:31PM

OK...You may have read my earlier post, Gas coming out of exhaust pipe?!?

I was told to remove exhaust & spark plug, then pedal for a few to get the excess gas out. So I did. Then I put in new plug & tried again, and it fired up on the FIRST PEDAL!(with no exhaust...damn that's loud!!)

BUT....

After running for 5-10 seconds, it dies. So i went through many of the older posts, and found a few that sounded just like mine. They say, check for fuel flow (fuel is flowing) clean carb (carb couldnt be cleaner) adjust idle screw (adjustments in process).

The thing that bothers me is the ped starts up (briefly) when the gas is turned off. When it is on, it doesnt start as easily, if at all. Also, it will run with either the choke on or off, though it runs better with the choke on.

ANYONE have any ideas? I'm frustrated! (and my legs are tired.)

oh yeah, the ped is a 79 vespa caio. Gas is fresh, oil is properly mixed, tank is a bit rusty, but I added 2 fuel filters to the fuel line, and there is no trace of rust by the time the gas reaches the carb. Exhaust port is not clogged.

Exhaust pipe sounds like there is sand inside, does anyone know a good way to clean them out? I heard draino works, but I'm kind of hesitant to try that. I read in the guide to use a torch or a hot coat hanger, is there an easier way?

Well, back to pedaling....

Re: so close...someone help!!!

Jim C. /

Sep 16, 2001 05:39PM

Your Vespa should start easily every time. Don't waste your time pedalling excessively. The motor is telling you something is wrong.

Running with the choke on tells you that there is insufficient fuel flow to the engine. You need to clean out the brass tube that sits above the main jet. Use a strand of telephone wire to carefully rod it out. If you have rust in the tank, this will be a recurring problem.

Jim

Re: so close...someone help!!!

don-ohio /

Sep 16, 2001 08:18PM

Could it be Jim that his float is sticking open and flooding him out and when he shuts the petcock he says it starts o.k.?That happened to me a few weeks ago with a Dellorto carb and I cleaned the needle vale and shimmed the plastic float and it's great ever since.

Re: so close...someone help!!!

Jim C. /

Sep 16, 2001 10:13PM

Don:

You are right on that one. Some float valves have a neoprene tip and this can sometimes crack and cause leakage too.

Don't know if this is the case here.

Re: so close...someone help!!!

don-ohio /

Sep 16, 2001 10:27PM

Well,Vespalad! You will let us know won't you? Every problem solved and reported helps me,I know,to get a better grasp of troubleshooting.`Cause I realize it's sometimes something `way off the wall' that surprises everyone.

hot coat hanger ?

Fred /

Sep 16, 2001 10:44PM

lol !

It doesn't say to use a hot coat hanger.

It says to attach a coat hanger to the muffler and then set the muffler into the fire.

The coat hanger is just to pull it out with.

(maybe I better go read it and make sure)

: )

vespa caio

leo /

Sep 18, 2001 01:50PM

vespa lad

i had the same problem...i thought everything was ok and was about to give

up when i fessed up and spent some real money and bought a correct fuel

petcock for my bravo....it worked. seems the fuel was just running on thru....

it helps if the carb is completely cleaned out too. a few threads ago someone

said to run wire thru that tube...i use guitar strings...i got a collection of 3 or 4.

you gotta be sure the float level is correct too. on my honda*s they are adjustable

but on vespa mopeds i think its not adjustable. your float may have a hole in it too

so take it out and shake it and see if some gas is not inside it. see if it actually

floats too...put it in a pan of water.

seems like its definitely a carburetor problem....you are really close to solving this

as for cleaning out the muffler...i cut the end off of mine back where it meets the

semi-round portion by the tailpipe...then reweld it on

SUCCESS!!!!!

Vespalad /

Sep 18, 2001 06:02PM

YES!!!!! The ped is up and running. My dumb ass forgot to screw the main jet back in. Just goes to prove that drinking beer and fixing mopeds are 2 hobbies that shouldn't be enjoyed together.

MANY MANY thanks to all who took time to give me advice...Please keep it coming!!!

The ped is running, but not as good as it could be. I have to keep the choke lever held down to ride with any speed. When you let off the choke, it looses power untill it dies, but if you turn the choke on just before it dies, it takes off again.

I was told that running with the choke on means there isn't enough fuel flow to the engine, and to clean the tube above the main jet. That tube is clean. What else could be restricting fuel flow? I am currently messing with the idle screw. And I was wodering if it is bad for the engine to ride with the choke constantly on? Will it foul the plug faster/worse?

Re: SUCCESS!!!!!

Chris S /

Sep 18, 2001 09:54PM

I've worked extensively on three Vespa mopeds (two Ciaos and a Grande).

If you need the choke to run, do you have an airbox and the screen filter element installed? Mine won't run without the airbox.

Here are some other Dell'Orto carburetor things I've discovered:

If ped runs but runs inconsistently at top speed, clean out banjo (with wire and carb cleaner).

If ped won't idle well (or won't idle at all) but will run with open throttle, check idle jet. You won't even know it has one if clogged. It is a tiny hole just below the brass fuel sprayers. Look inside from the engine manifold side. It is a hole in the metal casting. If it is clogged, you may not even see it. A guitar string or a strand from a brake cable works well.

If ped bogs down at full throttle, sounds like four-stroking. Check Fred's guide.

If ped runs with petcock closed but not open, check needle valve and/or float.

If engine races intermittently, check throttle cable for sticking, slide for wear, carb top for vacuum leak (by spraying carb cleaner or WD40 on it externally while engine runs...if engine suddenly runs faster, it is sucking the liquid in and therefore has a vacuum leak).

Make sure you adjust the idle screw at normal operating temperature.

Don't torque any of the screws on too tight, they will strip the carb body.

I hope this helps.

Re: SUCCESS!!!!!

ivan /

Sep 19, 2001 01:10AM

best thing to do is take the carb to a motorcycle shop and ask them to stick in the heavy duty cleaner and clean it out. the carb can be dirty in many places you can't get to so thats what i would do first. If you live in VA then you could bring it to my shop and we can fix it up really well for you.

Running like a champ

Vespalad /

Sep 19, 2001 02:29AM

Today I was setting the idle, and my engine was bogging at full throttle, but running like a champ on choke. I wondered if I had an air leak, since all the choke does is cut down the air in the mix. So I made sure my air filter was on real tight, it was kind of loose, but not too bad, so that didn't make any change. Then I covered the 3 holes on the air filter (where the air gets sucked in), & the engine died (duh). But when I only covered 2 of the holes, it pepped right up. And mean REALLY pepped up! I took it out for a spin, and that Vespa is crusing!! It runs at full throttle no problem, starts on the first pedal, plug is a beautiful tan color, purrs at idle, all the lights work... I couldn't ask for anything more. Well, it tops out at 24mph with me on it, 25-26 with my girlfriend, but that seems about right (Chris S, how fast do your ciao's run?) Tomorrow I will check the idle jet & see if it is clogged, and do a vacuum test. Any other tips to improve performance?

Re: Running like a champ

miguel /

Sep 19, 2001 01:04PM

congrats! and 25mph is a very good speed for a stock ciao. now if you want to start making racing/performance mods ... there's a long list of things to do. but first just enjoy the ride unless you really really really need the extra speed.

MOPED ARMY

Login or Create Account