Modern Vespa

So Ivana Tinkle's (Mrs jimc's) LX wouldn't start after a five-week lay-off. It had been somewhat reluctant for some time before that, but a new starter motor had improved it. But now it just wouldn't do anything but 'chug (silence)'.

A new battery didn't improve matters one bit - and the old one measured fine voltage-wise. So up on the lift it went, to check valve clearances. The exhaust was quite tight (less than 0.1mm) - and I found that the lock-nut on the adjuster was very stiff right at the point where it needed to be tightened a bit more. So that was the cause of the tight valve - the locknut had appeared to be snugged down when in fact the adjuster was still capable of some movement.

The spark plug was pretty sooty, mainly from all the duff start attempts, so a new one went in.

And now it's purring again, better than it's been for ages!

That tight locknut was a new one for me - perhaps it might explain some of the other 'hard start' reports.

Interesting. I'm assuming the threads are worn. Can a adjuster stud be replaced without disassembling the cylinder head? I might want to order a spare stud and lock nut to have on hand.

So you put the twinkle back into Ivanka. Very nice.

Well done. It's always nice when you finally get it figured out.