Modern Vespa

Hi folks

Im a newbie.

Rode 500 km on my aquired smallie without much info on its past.

On a trip, I suddenly lost power. Had real trouble in 4th gear, so had to drive in 3rd. Only managed to drive 60km/h. When I tried to get in in 4th, no respond. Back in 3rd. Managed to get to my destination in 3rd, although when we got there, we had to drive slow, which was almost impossible since i had to twist the throttle and engage the clutch to over-rev and keep pace.

Same situation later on when returning. A more experienced guy drove it home, only had to cover 5 km. Managed it. Have cleaned the carb.

Looking into the flywheel oil seal tmr.


From the legend's - any suggestions to troubleshoot this scenario?

All the best from Denmark


Cheers

Seal leak or possibly points related electronics.

Thanks.

If electronic related, how would you go ahead?

I'd start with taking a look at the plug, should give you an indication on what is going on.

If plug looks good, spark is next on the list. Cleaning the points and/or replacing condenser could help if it is a points ignition(not that familiar with the older ignitions honestly)

Agreed. If the plug is white or shows signs of detonation (e.g. small bits of aluminum on it), you should probably quit riding until you sort out the air leak or partially clogged jets.

If it's the ignition, you will usually also experience misfiring and spitback from the carb.

If you have a timing light, put it on and you'll probably see timing jumping around, along with missed strobes.

Once you've done some diagnosis, we can talk about next steps.

Could also be a restricted ( clogged) muffler ?