Modern Vespa

Hello all.

I have a 1980 100 smallie I haven't used for years and I'm in the process of reconditioning it.

I used to have a strange issue:

I remember that when I used to ride it, the carb would always rotate slowly slowly with every ride. I didn't matter how much I would tighten it.

For example, when I would attach the carb on the manifold, the filter and the plastic tray would be under the carb. But then slowly slowly the whole thing would rotate like 45 degrees.

Sometimes also when I would go over speed bumps the metal filter would hit the frame making a banging sound under my seat. The noise would happen only when riding alone and when the rear shock would decompress. I'm around 75kg btw if you are wondering.

I took out the carb to clean it the other day and noticed that 1 of the 4 pieces on the mouth of the carb has broke off. I'm guessing either I overtightened it, or it was one of the speed bumps (we have loads where I live) (see attachment)

Anyway, now I'm in the process of ordering parts.

Do you think I need a rear shock?
Should I get one including a spring too?

Could It be something else?

Thanks ever so much and apologies for my english.

It's hard to know what was happening with your carb, but it sounds like it needs an exorcism. Do a thorough assessment of the whole assembly. Why is it moving?

You will need a good shock absorber. Why not a new one? Some smallframes don't have much space between the spark plug cap and the frame above it and suspension is key. Especially if riding over bumps or riding two-up. Check your front suspension too. Let us know what you discover.

Thanks for the Reply,

Your cracked me up with the exorcism comment.

Good to know. I doubt the shocks have ever been changed so it will be good to change them.

The bike always had a few weird issues but I never found the time to sort them.

For example, pressing the rear brake when the idling would cut of the engine. Also sometimes the horn would randomly make faint noises. I think some cables must be shorting.

Also because the bellows where not installed properly and the carb running on an angle, it would leak fuel. So the whole engine is covered in soot.

This is how it looked in 2019.
Hopefully soon I'll have it back on the road.
I'll soon post pictures of the filter, just to show how much battering it took.

Image of the battered filter

When you will change the shock absorber don't forget about top and bottom rubbers.
It is also worth to check what bottom shock absorber bolt your Vespa have. M9 or M10? Most of new shock absorbers is for M10 bolt so if you have M9 you will also need new distance tube, M10 bolt and nut.