Vespa GT200 Backfiring, Stalling
Vespaman
travelling at speed and begin to throttle down, the engine backfires
4-5 times. Now, in addition to the backfiring, the engine is stalling
out at when I stop.
A friend told me that because I ride it nearly every day, on short (15
min/>5 mile) trips commuting to work and to the store, I'm getting
carbon build-up in the carburator. To cure this, he recommended taking
the bike out for long rides on the weekend to 'get the engine hot
enough to burn off these carbon deposits.'
I would like to hear opinions from the group as to how I might cure the
problem.
Thanks,
Chris
Gregg
piston and on the sparkplug.
Greg
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"Vespaman" <mydum...@gmail.com> wrote in message
news:1150570869.8...@i40g2000cwc.googlegroups.com...
SoCalMike
> My Vespa GT200 is 2 years old. The problem is that when I am
> travelling at speed and begin to throttle down, the engine backfires
> 4-5 times. Now, in addition to the backfiring, the engine is stalling
> out at when I stop.
the backfiring could be caused by a leak in the exhaust system, letting
air in. the stalling could be an intake air leak, which could make the
exhaust backfire as well, from running too lean.
id probably check all the bolts for the intake and exhaust,
how does it idle when cold?
whens the last time its had a tuneup? new plug, air filter?
>
> A friend told me that because I ride it nearly every day, on short (15
> min/>5 mile) trips commuting to work and to the store, I'm getting
> carbon build-up in the carburator. To cure this, he recommended taking
> the bike out for long rides on the weekend to 'get the engine hot
> enough to burn off these carbon deposits.'
a nice long ride with some high speed running wouldnt hurt, but i dont
think its going to solve anything.
SoCalMike
> Backfire: Either the valves need adjustment, or the timing is off
> (timing can affect idle also).
or an exhaust leak, definately. its a known issue on helixes and
burgmans, solved by new gaskets and/or tightening the fasteners.
Vespaman
turn and that seems to have cured the stalling problem. Still
backfiring on throttle-down. I guess I'll go and get a tune up at the
dealer. So in addition to oil change, spark plug, and air filter,
shall I ask them to check the valves, timing and exhaust?
I'm concerned that this might get expensive. Is it time consuming to
"check" these items?
Is it very difficult to DIY? I'm not a mechanic but I downloaded the
GT200 workshop manual on PDF, identified the idle speed screw and
adjusted it myself.
My local dealer kind of sucks. It's a large Harley-Davidson dealership
that also is a Vespa dealer. I needed to have some work done on the
headset and when I got the bike back, the glove box wouldn't open. I
asked them fix that onsite immediately. When they brought it out
again, the entire glove box was loose and rattled when I started it up.
I didn't leave and insisted that they find out what was wrong and
correct it. Turns out that the mechanic had forgotten to replace these
screw-holders when he reassembeled the glove box. This dealer keeps
absolutely no parts in stock. Everything takes 4-6 weeks to arrive and
must be paid for 100% up front.
Lee
> Thanks for all the input. I adjusted the idle speed screw a quarter
> turn and that seems to have cured the stalling problem. Still
> backfiring on throttle-down. I guess I'll go and get a tune up at the
> dealer. So in addition to oil change, spark plug, and air filter,
> shall I ask them to check the valves, timing and exhaust?
>
snip<
Sounds like valves, burnt inlet or maybe adjustment....a leaking exhaust
manifold can sometimes cause a backfire through the leak!!!!....(unburned
fuel).
Lee......
Honda Dylan SES125......
SoCalMike
> I suspect the parts problem is Vespa management; no dealer seems to
> have parts.
dealers dont want their money and spare room (if any) tied up in parts,
when they know they can make you wait for em. its not like theres an
option aside from waiting.