I've been lurking for about 2 years, figured I might as well officially join.

Purchased my s40 in Savannah, GA after a lovely lady from New Jersey totaled my vespa. The Vespa was a 1963 and I did all of the maintenance myself. I'm no star mechanic, but carb cleaning was not completely foreign to me. That being said, I'm still incredibly air headed sometimes, and apologize if this post causes excessive face-palming .

First! I've tried tuning the mixture screw and playing with the idle, while always making sure to stay at relatively high rpms. However, any day the weather is below 70, she just wont keep a steady idle regardless of how long I let her warm up with the choke half out. Infact, the engine flat out stalls, and then will only start up again with the choke in and lots of throttle. I read that this could be a carb problem, so that brings me to my second question!

Because school kept me so busy, I was resorting to sea foam for a quick cleanse rather than removing the carb entirely. I finally pulled out my carb a few days ago, and it didn't look too bad. only part that was even remotely dirty was the upper part of the carb, housing the (excuse my ignorance) big black rubber bowl thingy with the needle in it. I blasted the jets and carb with cleaner, wiped it all down with a microfiber cloth, Reinstalled the carb, and possibly sealed my doom when I set the gas lever thing to "Prime"? The engine spun and spun but would not start. I checked the screw at the bottom of the bowl to see if the gas was flowing, and it sure was. Emptied the bowl, tightened the screw back up, set the gas lever to "ON", and got the engine to start! Buuut it's not idling now.

And I forgot to mention the fun part, I spent so much time trying to get my bike to start, that I might have drained my battery, because the starter is spinning noticeably slower than before.

Save me you Savages, you're my only hope!

Dave wrote on 07/16/14 at 11:14:23:



I second the petcock issue.  From what you're describing, it sounds very similar to what my wife's bike does when the petcock is in the "On" or "Reserve" position.

I'm just waiting until I get paid on Friday to order a Raptor petcock.

Direct swap, except you have to plug the vacuum port on the front right side of the carburetor.  $26 from Bikebandit.com.  Here's the link:

http://www.bikebandit.com/search?q=5LP-24500-01

TerranTino wrote on 07/17/14 at 08:01:03:


No way to know over the internet.  If you try to charge it, and it doesn't hold a charge....then it is time for a new one.

Just purchased a battery tender that should do the job. I feel like a 12 year old charging up his RC car battery, running downstairs every minute only to be greeted by a red light.

Thanks for the help guys!