Modern Vespa

My 2009 GTS250ie is having an issue that my mechanic and I have not yet been able to resolve. We've gone through fuel system, air intake, checked for vaccuum issues, and even checked valves, rings, etc. Brand new battery. Bike starts up no problem, but if you rev it for awhile, or if you take it for a ride, it won't get over about 20mph and then it dies. It runs fine at idle, but starts sounding really rough once it is under load.

EDIT: One detail I accidentally omitted. The brand new battery keeps draining, even though it hasn't been run much at all. This is why I mentioned the variator. That's a simple check, but we've just not done it yet.

Things we haven't checked yet - variator and rollers, ecu, voltage regulator and whatever else we haven't thought of. Any ideas here? Need this running in time to head to PDX for Amerivespa.

Thanks for the advice!

Mark in Santa Cruz

I'd definitely remove the transmission cover and give all the transmission bits the once-over. A broken variator might well cause these symptoms.

The transmission doesn't explain the battery draining...but that's probably not related anyway. More likely, you have a parasitic drain on the battery from an accessory or have a loose connection that isn't allowing the battery to charge properly. Test those with a multimeter.

Ah - the battery drains as well.

I suspect stator damage - that happened to my GT200 in Italy while riding back from Greece. Very similar symptoms.

ya think this might give you a clue as what your issues are.

Yeah, after doing more diagnostics, I'm leaning towards the stator. I'm getting 0L resistance between all combinations of the 3 pins.

Do you mean open circuit or very low resistance? Very low is fine - open circuit not fine.

But a bad stator can be just the magnets broken up and graunching around the coils - doing possible damage in the meantime.

Meter didn't move off of 0L testing 1/2 1/3 2/3

Basically I wasn't getting any readings. In any case, I think my next step is to pull it apart and take a look.

I suspect "0L" is ambiguous to the OP. Touch the meter leads together; if "0L" then you have Zero (or very low) resistance. If "0L" when the leads are not touching, then "0L" means "Open circuit" -- and there's something wrong with the stator.

You've slightly confused me. When leads are not touching it reads 0L. When leads are touched together, I get a reading, though resistance is very low, obviously. When I touch leads to pins, I get 0L. In any case, I'm pulling the flywheel to check on things.

Sorry, didn't mean to cause more confusion. *

In your case, "0L" on the meter means you have an open circuit, i.e. a very high resistance. If you measure that on the stator pins that means there's an open circuit in the stator. Not good. When you pull the flywheel look for broken wires or burned spots. Good luck!

* Just trying to explain your "0L" reading. Different meters display various messages to say "Open circuit". Some, like my cheapo Harbor Freight meter, read "1(blank)(blank)(blank)". A more expensive meter might say "0PEn" or some other word that can be written on a numeric display.

Okay, so I still haven't figured this damn thing out. I've got spark, fuel is making it through the injector, the condenser tests good as does the coil. I can barely get it started and it barely runs when it does start. I have the FXTUL and it is giving no errors. The stator is testing okay, and my 0L was a false reading. The spark plug wire has the right resistance, but the insulation was cracking so I replaced it with the exorbitantly priced one from Scooterwest.

Is there any way this could be the ECU? Is there a way to test this without replacing the ECU, or does anybody in the SF Bay area have an ECU with keys they'd lend me? Or ship me and I'd pay for shipping and sending it back.

I don't want to drop 1k on an ECU to figure out that it isn't the problem.

Ideas?

Thanks folks!

It's not the exhaust partially blocked is it? Eg the cat dying?

I only ask because you didn't mention it and it does go up to 20mph ok ...

Well, haven't checked that, so adding it to list. Thanks

How about fuel pressure?

I mean, it could be, but the injector seems to be working as expected. It is probably something really stupid that we are missing, though, now that we've tested all the PITA stuff.

In what way? False reading or pilot error? Not going above 20mph sounds suspiciously like a 'limp-home' setting.

A good dealer will try a temporary substitute ECU.

Sadly, Piaggio have pissed off most of the good ones - only 24 left in the UK - it was 33 last September! The same seems to happen in the US as well.

I'm going to call pilot error. I got the reading of 0L, then tried again a few days later and got a legit reading. In any case, we pulled the pump to get to the stator and got a good reading.

I don't have any "good" dealers that near me anymore. Probably going to have to take it the 80miles or so up to SF or surrounds.

Thanks for the reply.

Mark

Somewhat incorrect.

If you touch the leads together should never get OL on ohm setting on a multimeter, should read 0.0 or very close as the leads themselves have some resistance. OL stands for "over limit" which means that the reading is outside the meter's measurement range or open circuit.

Agree, just throwing out thoughts.