Modern Vespa

1980 P200E

I added a better exhaust. It idle well but would cut out while riding in top gears at higher RPMs. I changed out the air corrector. Top end is much better but does not like to stay idling when cold. I feather it on cold starts. Did not have that problem before.

Carb is a 24/24, air corrector was a 190 change to 140, mixer BE4, main jet 116 and idle is 50/120.

My best guess is it's sucking to much fuel when cold?

When you say "cut out," are you sure you don't actually mean "soft seize?"

You may have damaged things enough to reduce compression, but not enough to keep it from running.

The AC190/BE4/116 50/120 is stock German jetting. Scooter a long way from home?

It was more like it ran out of fuel. I coasted in a parking lot and it kicked right back on. That happened twice on hard excel up a hill. It kicked back on with ease.

It has been in Iowa since 86 from a license plate that came with it.

hmmm...fuel starvation isn't like that. It stutters like it's hitting a governor and can, if you're unlucky, lead to a seize.

I think you soft-seized it and have possibly done a little bit of damage to the ring channels in the piston.

You most likely need to take a look at your jetting and up the main, though. Is it a stock top end?

It probably soft seized on me. The top end is bone stock. I am waiting on some bigger main jets to arrive.

Good plan.

Since it's still running, you can probably learn to live with the poor idle and see if it corrects itself. You might also see if you can borrow a compression tester from your local auto parts store and check your compression. That'll give you some idea of where you're at in terms of needing to take action.

It idled fine when cold before I swapped the air corrector so I might fiddle with changing the idle jet as well.

chandlerman Thank you for your help and replies.

I forget the SIP road exhaust bolts keeps coming undone. Some quick tightening and it kicks right over. I hit the cylinder with a compression tester and it's coming in around 100 psi. Not the best but good enough for now.