Modern Vespa

Hello,

Rusty has a misalign rear wheel, it is not centered into the chassis.



The wheel is perfectly straight, swing arm bushings are brand new (it was tilted before rebuilt !)



The drum does not go all the way onto the splines, there is around 8mm missing



Is this normal ?

The engine has an inside oil seal and an outside bearing



The bearing is supposed to be flush to the circlip right ? The only way for the drum to be centered to the chassis would be for it to go further inside into the engine case, but it would not be possible there !

The brake drum is this one : made to fit internal oil seal

https://eu.rondaleyscooters.com/products/fa-italia-rear-hub?shpxid=866a1bf1-f117-4208-b903-c31a196ef19a

The engine is at the right place, the chassis is straight !!

I'm lost on that one !

Hallo Colin

Do not stress. I have two PX's and their rear wheels are slanted the same as yours.

I am pretty sure the wheel is angled sligbtly to offset the weight imbalance caused by the engine and gearbox that sits on the right hand side.

Not sure about that ! I've seen some PX with the rear wheel perfectly centered !

To counter effect the imbalance due to the weight, the wheel should be further to the right, not to the left !

Not the first or last time I assume wrongly.

Rear wheel alignment

This relates to tilted wheel, which was also my case, but with new bushing my wheel is perfectly vertical, it is just not centered compared to the middle line of the chassis, and i can't figure out why ! Obviously something is wrong, but what ?

I had the same issue on a VNA. The frame was twisted pretty badly. Not saying that's your issue but I too thought it was the swing arm bushings, replaced those and it was the same.

Got a new frame off GeekLion here and that solved the issue.

I took the paint off the frame, it was the original paint, some surface rust was there, but no sign of accident at all ! And all the parts were original. I really don't think the frame is bent

I think you've answered your own question. That looks to be the wrong axle, so the wheel is sitting too far over.

The wheel should be centered unless, like in FM's case, the frame is bent or the shock bushings are thrashed, which causes the tilt you already fixed.

I think the installation order of your axle seal and bearing are reversed. The seal on my 80 P125X is on the outside. If your seal is on the inside this would limit the insertion length of the axle.

With that said, the drum, axle, bearing and seal have to work together. If the drum you have, replaced a drum that was designed for external seals, then all bets are off. I don't think you can just change the orientation of the seal from outside to inside. What's the advantage of the internal oil seal? Seems like it would be a P.I.A. to replace!

Hec

just to play devil's advocate here: you don't have the wheel on backward, do you?


(I know, I know, I'm just checking!)

'Tilted Wheel', thats a great name for a band.

As a reference look at the distance between, tire and rear brake arm that rear brake cable is mounted into in both pictures. Something didn't get put back together correctly or is wrong part. You can see the difference in those two pictures.

If you mounted a wide wheel setup on there it woukd,be about right.

If backward the wheel would be further more to the left side !

I say something is off with your bushings or frame. Hub looks OK, all hubs can work on the internal seal axle. The gap you get in the splines looks normal. If the splines reached the end then the washer wouldn't do its job, tightening the hub to the bearing's inner race…

Did you center the bushings when you installed them?? Also, if it's possible flip over the scooter and take some measurements to see if the engine cases are centered in the frame…

My engine, Motovespa Px200 iris should be similar to the Px200 arcobaleno, the seal goes inside the case, you can't flip them for 2 reasons, the bearing would not fit inside (too big) and the seal would be way to smal outside. The arco engine has been designed like this, there is even a small hole under the casing in case of oil going through the seal, it is evacuated to the floor and not to the wheel axle and the brakes !

It's pretty common to replace the inside seal with the outside version and plug the weep hole, as that inside seal was done for legal vs practical reasons.

Did you replace the swingarm bushings?
If not, maybe you could get a friend to sit on it (center stand up) and shake it side to side.
Wheel looks tilted.

True Yes I did + you can't really mount them not centered as there is a stop washer into to swing arm on both sides.

I took some measurements with a laser, the wheel is perfectly in line from front to back compared to center chassis line







I scraped the original paint and apart from surface rust, everything is fine, no damage to the chassis, I mean nothing visible...

Maybe the swing arm left and right tolerances are off from factory ? Spanish Vespa, could be... I could cut at the right side a 1cm piece and stick it to the left side ! I have a massive band saw, I really could do that

The drum comes flush to the plate, seems normal ?



The gap in between the tire and the clutch cover is around 15mm, sounds good to you ?

Swingarm bushings are new. The second picture is the scoot when I got it, the first one is now ! On the first one it could look a hair tilted but that comes from the lens distortion. On the second picture it is crazy tilt, that was before I replaced the bushings

Perfect gap. Issue is not the engine itself.

Not all engine mount bushings fit correctly, any picture of those installed?

You mean into the frame ? I'll do some pictures this week end (my shop is not at my home)

Into the engine

I don't have pics before engine into the frame. Could they be wrong ? I took some I had here from a mistaken order before. They were sold to fit PX engines. Maybe there are different ones ? Are they supposed to be different size/length from right or left ?

T5 bushings are different, BGM does them…

There are washers in before the mounts. Mounts vary in size, as do cases and washers. All have to fit together for the engine to be symmetrical. And stay symmetrical.

I'll take pictures of the engine into the frame on each side of the swingarm to see if it centered