Modern Vespa

Hey guys, sorry if this is a redundant topic, but I couldn't search through the 1600 posts to see if one fit.

Cruising at 50mph, running great, came to a stop light and the bike died. It had been having trouble idling a bit at times and died at the light a couple of times in the last few weeks (since I changed from regular to synthetic pre-mix ??). Easy enough to restart (though I wish I didn't have to). But this time it wouldn't restart, either kicking it or using the starter. It just won't catch or turn over. I tried jump starting it (since I was on a hill). No joy (does that even work? I've never tried before). It felt like it was trying to start but just wouldn't turn over. I changed the spark plug to see if it was fouled. No joy. How can I test to see if the plug is getting electricity? New battery. The horn works. The tail light goes on when I kick it. I don't see any of the instrument lights come on when I turn on the ignition though. Should they or should it be running for them to come on?
I can see that gas is spurting into the carb when I kick it, so I don't think its a fuel issue. But what do I know.
Would the change to synthetic make a difference? I only have 1000miles on it. Polini 177. Vortex Carb.
Can someone lead me through some basic checks? Changing the plug and taking off the carb cover is pretty much the extent of my mechanical prowess. Pathetic I know, but I need to learn

Thanks!!

First, pull the spark plug.

Second, put the cap back on the plug with it removed.

Third, touch plug to ground (engine case works well) while holding the plug wire in an area where you will not get shocked. Kick the bike over or use the starter while holding it to ground and watch for spark.

The engine needs three things. Fuel, air and spark.....forget about synthetic oil and all that for now.....check the spark first.

Your engine needs three basic things to run....

Fuel.

Spark.

Compression.

It sounds like you are getting fuel.

Time to pull the spark plug out of the head, reattach it to the lead from the coil and hold it against some bare metal on the engine case while kicking the engine over. You should see a fat blue spark. If you don't, we need to start doing other tests.

I tank you managed to typ just a little faster than I did.....

Hey Dave...this is Will from Denver....I am assuming your the Dave from Waterford....nice meeting you last weekend at the Rally! Learn to type (and ride) faster! LOL....just kidding

Ok. I've got a spark.
Btw, Should the instrument cluster light up when the ignition is on without the engine going? It's on '05.

Hi, I wouldn`t have thought that changing the oil type would cause any problems, (assuming you used a specific 2-stroke oil and not a car type?). Also I assume from the age of the scooters you list that they are autolube, but you mention pre-mix?
To check for a spark at the plug, remove the spark plug from the engine, re-attach the plug cap and lay the plug on a metal part of the engine. (preferably not near the spark plug hole so as not to ignite any fuel vapour). Crank the engine with the starter or kick start and if all is well you should see a nice fat blue spark jump between the plug electrodes.
Your symptoms could also be caused by a blocked idle jet in the carburettor, this would require the carb. to be stripped and cleaned and the jets blown through with compressed air.
Hope this helps and you get your problem resolved.

Yes, some super quick typists on this site!!

The guy I bought it from purposefully plugged the autolube somehow, so I've been having to pre-mix. I hope to restore the autolube someday. Is there a way to test for this? It's a Vortex. Would I be able to strip and clean it having never done it?

can you tell if there is enough gas coming through? (see vid link below)
it doesn't squirt, but gets everything wet and creates a fine mist when I kick it. I did clean the carb fuel filter (it was fine with just some sediment below it that I cleaned out) and checked that the float was working ok. It was full of fuel. When I tried to start it after I reassembled everything, I got a large 'POP!'. Backfire?

https://drive.google.com/file/d/0Bxpt-uLULZ00SDN4a3VkeUpiRTQ/view?usp=sharing

Is there a way to test for this? It's a Vortex. Would I be able to strip and clean it having never done it?[/quote]

Yes it's an easy enough job with simple tools. Screwdrivers and a socket set would be all you need. Links to carb rebuilds are plentiful. Here's a few below. a carb cleaning would be an excellent idea and good measure even if it's not the issue.

Awesome, thanks so much. Does the Vortex need any special treatment? It looks different, so I'm curious if it has any different screws or assembly issues when taking it off and cleaning it.

I guess I'll also need some type of carb cleaner?

Hah! I can ride faster....the machine can't. Some of the road conditions didn't really help. More than once I ended up jumping the poor thing working to keep up!

Pulled the carb and cleaned it. No luck but very educational.

Feels like I'm getting compression when I kick it over. If it seized, would I even be able to kick it over?

The washer around the banjo bolt is torn up for some reason, but it still didn't start when I put a teaspoon of gas down the carb. There was plenty of fuel in the float chamber, so think it's getting enough gas.

Theres a spark, but I don't know how fat it's supposed to be. I did backfire one or twice. Is there an easy way to test the CDI to know if it's working as it should?

Any other suggestions? Hellllpppp!

Maybe I am reading your problem differently than anyone else. You are saying that the engine wouldn't turn over? well, if that is the case then no matter how good the spark plug or wether you are getting fuel o not wouldn't matter. If the engine wouldn't turn over that means that you have something mechanical "locking" (not allowing) the movement.

Your best bet would be removing the cylinder head and trying to see if the piston is locked. Look for groves on the cylinder wall, you might have a catastrophic engine failure.

You might also have seized the piston by over heating it (it expands and it locks in a cylinder wall).

I can kick it and it spins freely like it's trying to start, it's just not catching. Is this symptomatic of a seizure? I thought the kick start wouldn't even kick if it was seized?
When I tried to jump starting rolling down hill, and popped the clutch, I felt like it was turning over but wouldn't keep going.

I think most ppl here refer to a motor 'turning over' when it will freely rotate whether or not it will catch & run by itself. If it will catch and keep going we might say that it 'runs' rather than that it now turns over. Ads selling old scooters often mention something like "Doesn't run, but motor turns over & has good compression" to indicate the motor is not frozen and may need just carb or ignition work.

I think you meant:
"When I tried to jump starting rolling down hill, and popped the clutch, I felt like it was turning over firing, but wouldn't keep going."

Did you try to pull the clutch back in & rev the motor out?

Opinion: More likely a fuel starvation or flooding problem than an ignition problem.
Pull your plug and check if it's wet or dry. It it's wet, you're flooded now. Dry the plug best you can if you don't have a fresh one to swap, close the fuel tap, open the throttle & kick it over 10 or 15 times before you put the plug back in to clear it out a little(also double check for good spark now). Now kick it over w/throttle open & fuel tap still closed.

How is your fuel flow at the carb? Clogged tank filter, dicey tap or kinked fuel line all can cause intermittent problems. How full is your tank? If low, some bikes don't like it and can starve w/ gas still in the tank. OTH if your float needle is leaky with lots of gas available at the carb, it may be slowly drowning when you pull up to a light. So... plug, wet or dry? Did you clean off the dirt inside & out or that and also blow air thru all the passages and jets? If you don't have compressed air, it may still have a plugged passage. What color is the float needle tip?

As you might guess from all the questions, it could be a lot of things. Hang in there & learn, I think we've most all had the same or similar problem.

Still wouldn't hurt to check the cdi and pick up coil with a multimeter. I suggest you get a Haynes manual. Shows you how to do it and the readings you should get.

This manual?: http://www.vespaclub.org.pl/images/manualki/px/WorkshopMan_PX.pdf

I found the electrical section but didn't see how to check or what numbers I'm looking for. Can someone help me to see or understand it?

Sad news guys. After trying all of the above to no avail, I had it taken to Massimos (if you need a cheap tow in Orange County, CA let me know).

The verdict: blown piston ring!!

How could that have happened? Anybody?