Modern Vespa

Hello. I currently have my P200E with the malossi 210 splitted open because I was replacing the kick start gear. Before I finish the engine I would like your help identifying what seems to be (I believe) a common discrepancy.

The engine hesitates hard only on second gear and third gear under heavy load. Imagine that you are accelerating and right in the middle of the acceleration imagine pulling the clutch lever in and reving the engine more and letting the clutch lever go again, kind of like "popping the clutch when you do a wheelie). In reality , the problem is not the engine, the engine pulls hard, it just something on the drivetrain causing it to yank.

The situation has been very annoying, unsafe and embarrassing. Annoying because the scooter jerks in the middle of the acceleration, unsafe because when I ride with my son under the acceleration the scooter yanks you back and then forward and embarrassing because I create often a situation where people on cars races me just because they think I am "racing" pulling the clutch.

English is not my first language so I don't know what words to use to best describe the situation. I googled it using my own words but I am not finding anything. I purchased a new cruciform(I haven't installed it yet). The gears go in just fine. Is the current cruciform not holding the gears on place?

I would like to get this situation resolved before closing the cases. Thanks a lot!

My first thought is maybe it feels like the clutch is slipping because the clutch IS slipping. What do you have for a clutch? How do the linings and plates look?

Uhmmm, great question. This was a franskeinstein project that we put together. It was originally a 200cc engine with worn-out cases. I purchased new cases a few years ago and put all the drivetrain that came with it. I know 100% that it has P200E gearing because compared to the original PX150 motor the gearing is much taller. I think I might have to take a look.

One thing that I found is that it had almost no oil on it. Either it had a leak somewhere or the shop never put enough oil a few years back. This could well be the culprit.

I did an engine split on the frame but I could remove the clutch and take a look. I also purchased the brass small pusher for the clutch lever(not installed yet).

This is how much oil came out when I drained it:





Last edited by scooterist on Mon Nov 01, 2021 11:46 am; edited 1 time in total

My first thought was clutch slipping, too, but that doesn't usually produce the jerking. Maybe some bent plates?

Look at if the tabs on the plates are deformed. Even if they weren't it doesn't take a lot of jerkiness to put them in a bad way, and once it starts, nothing fixes it but new plates.


Maybe not that bad, but you get the idea...

I am going to have to pull the clutch then. I have no idea what clutch I am running, let me remove it and get back in a few.

While you have the clutch torn down, check the bronze bushing. If it's even a little bit loose, it can cause jerkiness, too and is a cheap n' easy thing to fix/replace.

I theory, you should replace it any time you replace the clutch plates, but most people only replace it once it starts failing (myself included).

The brass bushing looks ok. Unfortunately I could not locate the castle nut and I am going to have to order a new one. I look hard for the last 25-30 minutes. It kick in the balls because I was literally in the process or organizing all my scooter tools and spare parts bins.

Within the last 2 months I have done an insane amount of maintenance fixing, replacing several parts every week. The tool will appear somewhere but I think I am going to place a new order of more stuff.

Don't order a castle nut. Order a flanged hex nut to replace it. It makes clutch removal and replacement orders of magnitude more pleasant.

Only the removal side of the castle nut tool should show any wear.

^^ Send me a link of the part if you don't mind. What rev counter/tach do you recommend?
On another note, I found the main rivet holding the stator to the stator plate lose, it wiggles and it might have been touching the flywheel slightly. I have a spare stator(5 wires) I just don't know how I would fix the stator. I can weld it, I can glue it, I can put a shadow screw and a nut(maybe), I can try putting a new rivet.

I don't know...!! I never done it, it is a rare failure. the scooter runs well, all the lights etc but eventually it will groove the inside of the flywheel. Pictures in a second.

As you can see on the pictures, not only the stator fixture moves up and down from the actual plate but if you look at the rivet you will see that there is a gap on the left and on the right so technically it moves up and down and side to side about 2mm.









Last edited by scooterist on Mon Nov 01, 2021 1:39 pm; edited 1 time in total

Here it is on Scooter-Center. It's an M12x1.50 flange nut.

Truly life-changing if you tend to go through clutches and blow up motors on a regular basis.

^^ oh yeah, I recently got one installed. I was under the impression that this style nut was for the PX with the cosa clutch. I recently purchased a cosa clutch for my LML engine and the seller told me to go with that exact nut instead of the castle nut. There is also a wavy nut washer that goes along with it.

Think it's this one
https://www.scooter-center.com/en/clutch-nut-m12-x-1.50-collar-oe-18.6mm-h-9mm-ws-17-bgm-pro-can-be-used-as-castle-nut-for-vespa-px-rally180-vsd1t-rally200-vse1t-sprint-t5-125cc-cosa1-7671201?number=7671201
Anything but a castle nut.
If gear is jumping, mostly in 2nd or 3rd, then new cruciform and gear selector box will fix it.

^^ I got a new rounded original piaggio cruciform(not installed yet). As far is the selector box, are you talking about the one with the two cables? I think I have a couple of them spares.