Modern Vespa

Fellow scooterist,

My brand spanking new engine is built, I got brand new engine cases and cylinder/piston from Sooterwest, new gaskets and seals.

My mechanics put the engine together, they say that it has great compression, it starts on the first kick, it idles great but they are telling me that it feels slugish when you are on gear on the test ride.

What could it be?, I am running a bone stock set up with a 24/24 del orto carb, a new P200 engine, the carburator jetting as per the Vespa book and a sito plus.

They are saying that it could be the ignition, or even a plugged Sito plus or electrical box(I don't know exactly what they meant).

Can you guys piggyback and tell me what else could it be? I am running a new spark plug, new exhaust spiget, good gas and good motul full shyntetic oil. What could it be?

1) timing?

2) check that the exhaust is unobstructed, as mentioned.

3) something else

Could be a mechanic problem.

Take it back to your mechanic and let them resolve it.

What is your top speed? Should be able to get to at least 60 mph with that setup, probably 65 on a flat road and no wind. note: you probably shouldn't know yet with a brand new rebuld as you should have at least 100 miles on it before opening it up all the way.

What size is your main jet? I think I was running a 118 main with the same setup.

What does your plug color look like? Should be a light mocha color after a few days riding (i.e. at least 100 miles).

btw, if it is your electronic ignition box your scooter will not run. In my experience it either runs and its something else (like carb. settings) or it will not start (very weak spark if any at all). Spark should be a bright white if you watch the plug grounded to the case.

Has anybody confirmed your timing? There are good writeups on Modern Vespa and elsewhere on the 'Net that show how to obtain top-dead-center and use a cheap dial guage to get it darn close to factory settings.

So I just got back from the shop, the main mechanic wasn't there but the set up is a a stock P200E engine set up with the 24 carb and all the stock jetting like the 50-160 BE3 with 118 main jet and 1 and 3/4 turn on the mixture screw on the back of the carb. The negine strats well but the moment you give gas it bogs down so bad that it wants to die inmediately, oddly enough it iddles well.

We think is a jetting issue. We haven't mess with the stator markings, we left it stock. I am running a blue ducati CDI/coil. We also put fresh gas.

I would not trust the marks. I would find the timing again.

Follow the suggestions given re checking timing etc but also be aware that P/PX200's can vary enormously in performance for no apparent reason.

I've had sluggish stock bikes that were transformed by doing nothing other than swopping the topend yet, when you examine them looking for differences there is nothing apparent in the porting, clearances, deck heights or compression - go figure.

Years ago I had a bogging issue at about 1/3 throttle. Confounded me. I called Sportique and talked to Daniel (he's not there anymore but they are still good about advice). I told him my main stack, my idle and that other jet by itself (can't recall the name right now ). I told him my elevation and he reeled off the correct numbers for all the jets. I think I got two or three (at least the BE3 and main jet for sure) according to what he said.

The bogging went completely away.

How is your plug color?

The thing is that starting with the stock set up is the right thing to do. We are moving to the carb jets and start from there. The engine is completely dying, you can't even rev once. The moment that you twist the gas handle is bogs down and it feels the same as when you engage the kill switch.

Now it sounds like a marginal electronic ignition module. Who washed the scooter and didn't dry that area around thoroughly before starting it?

Wow, feeling sluggish is quite a lot different to completely dying

Sorry I can't help.

Is it a new sito plus exhaust?

I had a problem a while back with a rebuilt high mileage engine bogging and an old shitty exhaust. Put a clean new exhaust on the new clean engine and it will help.

If that doesn't work check your timing.

I'm confused, why are YOU trying to fix this. Didn't the mechanic do the rebuild? What mechanic does a rebuild takes it around the block and hands it back saying,"it's running sluggish, good luck." If it's a timing, jetting, etc. problem, it's the mechanic's responsibility to have that worked out.