Modern Vespa

So I was looking for info/advise.
I have a 2015 BV350 with just about 5k. It stalls within 15 seconds of starting. Then unpredictable runs rough. I have dipped my gas tank to test for water. I have Chevron with techron the first tank it seemed to clear up. when I filled it up on the second tank half way through the trouble has come back. I checked the spark plug boot and the spark plug everything looks ok. I opened the air box shook out the filter wiped oily residue.

I'm ready to pull the ecu/throttle body out to clean and check the passages.

Any ideas or experience on this would be fantastic.

Thanks
John

I know other's have experienced this to various degrees. There is an engine mapping update that your Vespa dealer can apply to the ECU that should help with this.

Also, for some people, the evap canister can cause some issues. Try loosening your gas cap so that it's not completely seals and air can get in and see if it still runs rough. It normally should vent through the evap system, but the general consensus seems to be that it causes more problems than it fixes. The next time breaknwind helps me work on mine (probably at my 12,000 mile service in a couple of months) I'm going to ask him about removing mine because while I wasn't having issues before, I am starting to now. Kept having it die on me when cold if I didn't give it a little gas. It stopped once I unscrewed the gas cap, so I'm pretty sure it's the evap system causing it for me.

not a new problem...for me I believe it's the EVAP system, solution I employ is fill with gas carefully.

https://modernvespa.com/forum/topic141198?highlight=evap

I've heard of the Kill Switch causing trouble like this. The German forum http://www.beverlyforum.de members have reported that this causes stalling or failure to start.

It's worth giving it a blast with contact spray and wiggling it a bit.

A problem with the side-stand cut-off was also mentioned once. But the usual culprits are mostly the spark plug or especially a cracked cap

Alan

These are all good standard reply's to your problem. I haven't swapped the plug cap on my 2015 bike yet. I just got to 625 miles, so this weekend I'm doing the service.
Another thing to try is check the spark plug for tightness. There has been one thread on this forum where that was the problem.
Start with the easy solutions first 8)

The more I work on my bikes, the easier it gets. See you in a couple of months

I pulled the spark plug boot I did not see any white residue, I also checked in the dark I did not see any arcing either. I pulled off the boot / hose from the air box to the throttle body. I stuck the straw in the bypass hole and sprayed Several times. I started the engine and sprayed while running ie. it still ran rough and stalled. I noticed yesterday some muffler popping on decel When hot. I notice the idle is dancing hi and low.


John

Did you check the spark plug for tightness? Being a 2015, it should have the latest mapping update. That doesn't mean it's not faulty. My 2014 started popping a lot before it started stalling at every idle. Hasn't had a problem since they hooked it up to the laptop and charged me $100.

I had the spark plug out to check it felt normal coming out and back in.

John

That's normal. It happens on mine and I've seen it mentioned on here by others as well. I notice it most when I've been riding 15+ minutes at 60+ mph and just let go of the throttle completely to engine brake.