OP
@mike_m avatar
UTC

Hooked
1986 Vespa PX 125E, Pinasco 177
Joined: UTC
Posts: 127
Location: Toronto and Halifax
 
Hooked
@mike_m avatar
1986 Vespa PX 125E, Pinasco 177
Joined: UTC
Posts: 127
Location: Toronto and Halifax
UTC quote
I need to rebuild the engine on my 86"PX125E. The flywheel side bearing is shot causing a wobble that is burning out my stator.

I want to do this as quickly, but as reliably as possible. What parts should I order since the cases will be split?

Thanks
@quasi-moto avatar
UTC

Veni, Vidi, Posti
SawStop
Joined: UTC
Posts: 5391
Location: Puyallup, WA
 
Veni, Vidi, Posti
@quasi-moto avatar
SawStop
Joined: UTC
Posts: 5391
Location: Puyallup, WA
UTC quote
Since the cases are already split, change out all the bearings and seals, the rubber for the kickstart quadrant, and the shifting cross. I'd also take the opportunity to rebuild the clutch (you can get a rebuild kit from Motorsport, I think.)

I'd buy all the gaskets in a kit.
OP
@mike_m avatar
UTC

Hooked
1986 Vespa PX 125E, Pinasco 177
Joined: UTC
Posts: 127
Location: Toronto and Halifax
 
Hooked
@mike_m avatar
1986 Vespa PX 125E, Pinasco 177
Joined: UTC
Posts: 127
Location: Toronto and Halifax
UTC quote
THe bike is showing 33,000kms so I'm wondering if it would make more sense to buy a new engine & install and rebuild the old one over the winter?
@xantufrog avatar
UTC

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: UTC
Posts: 8892
Location: Atlanta, GA
 
Moderibbit
@xantufrog avatar
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: UTC
Posts: 8892
Location: Atlanta, GA
UTC quote
Mike M wrote:
THe bike is showing 33,000kms so I'm wondering if it would make more sense to buy a new engine & install and rebuild the old one over the winter?
Why? 20,000 miles is not that bad. I guess if you have tons of money laying around for a new engine...

In addition to the things Len said to replace, also replace the kickstart gear while you are in there (not the quadrant but the little soft gear it engages with).

Check the gear shim for tolerances.

Buy some new piston rings to tighten up your top end.

Check the other bearings for slop.
OP
@mike_m avatar
UTC

Hooked
1986 Vespa PX 125E, Pinasco 177
Joined: UTC
Posts: 127
Location: Toronto and Halifax
 
Hooked
@mike_m avatar
1986 Vespa PX 125E, Pinasco 177
Joined: UTC
Posts: 127
Location: Toronto and Halifax
UTC quote
I just put a brand new Pinasco 177kit on the top end last year, which has ran fine without issues. How long would it take someone who is averagely mechanically inclined to do the rebuild?
@xantufrog avatar
UTC

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: UTC
Posts: 8892
Location: Atlanta, GA
 
Moderibbit
@xantufrog avatar
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: UTC
Posts: 8892
Location: Atlanta, GA
UTC quote
Mike M wrote:
I just put a brand new Pinasco 177kit on the top end last year, which has ran fine without issues. How long would it take someone who is averagely mechanically inclined to do the rebuild?
Ah, forget the rings then. It might take a week or so. It's not that bad. Take pictures along the way, use Vespamaintenance.com for a reference, and don't overtighten things when putting back together.
@quasi-moto avatar
UTC

Veni, Vidi, Posti
SawStop
Joined: UTC
Posts: 5391
Location: Puyallup, WA
 
Veni, Vidi, Posti
@quasi-moto avatar
SawStop
Joined: UTC
Posts: 5391
Location: Puyallup, WA
UTC quote
Mike M wrote:
THe bike is showing 33,000kms so I'm wondering if it would make more sense to buy a new engine & install and rebuild the old one over the winter?
If it were me, I'd rebuild the old one. As you'll see when you open it up (or maybe you've already noticed) the craftsmanship and quality of those motors is just so much better than the new LML ones.

I'm always amazed at the precision of the gear stack and other parts that were machined before CNC technology. The castings were better, smoother and each part seems like it was meant to be on display. Modern parts seem to have more sharp edges, burrs, and just seem to have been made with "how cheaply something can be done" in mind.

That's all just my opinion of course, and I'm sure others have different points of view.
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⚠️ Last edited by Quasi-moto on UTC; edited 2 times
@n8murphy avatar
UTC

Hooked
62 vbb ratbike, 64 vbb,56 bella r201
Joined: UTC
Posts: 169
Location: salem MA
 
Hooked
@n8murphy avatar
62 vbb ratbike, 64 vbb,56 bella r201
Joined: UTC
Posts: 169
Location: salem MA
UTC quote
you will need certain special tools as well like a flywheel puller, clutch tool, and if you are removing the crank you need a couple other tools as well
@jamesjohn avatar
UTC

Ossessionato
1970 Vespa Rally 180
Joined: UTC
Posts: 4145
Location: Denton Tx.
 
Ossessionato
@jamesjohn avatar
1970 Vespa Rally 180
Joined: UTC
Posts: 4145
Location: Denton Tx.
UTC quote
Len Smith wrote:
Mike M wrote:
THe bike is showing 33,000kms so I'm wondering if it would make more sense to buy a new engine & install and rebuild the old one over the winter?
If it were me, I'd rebuild the old one. As you'll see when you open it up (or maybe you've already noticed) the craftsmanship and quality of those motors is just so much better than the new LML ones.

I'm always amazed at the precision of the gear stack and other parts that were machined before CNC technology. The castings were better, smoother and each part seems like it was meant to be on display. Modern parts seem to have more sharp edges, burrs, and just seem to have been made with "how cheaply something can be done" in mind.

That's all just my opinion of course, and I'm sure others have different points of view.
i completely agree. i have a slow rpm grinder i usually use for sharpening chef's knives that i use to shave down parts. all the cruciforms i get have to be cleaned up before they will fit the tolerances of my Italian parts.

its nice to have the leather wheel as well for polishing. usually its for the last bit when doing knives.
OP
@mike_m avatar
UTC

Hooked
1986 Vespa PX 125E, Pinasco 177
Joined: UTC
Posts: 127
Location: Toronto and Halifax
 
Hooked
@mike_m avatar
1986 Vespa PX 125E, Pinasco 177
Joined: UTC
Posts: 127
Location: Toronto and Halifax
UTC quote
I've been shopping and I plan on ordering the following for the rebuild:

- PX Seal Set with 30mm rear hub (how do I know if my hub is 30mm)
- PX Gasket set with o rings
- Carb Rebuild Kit with base gaskets
- PX Bearing Set
- Cruciform
- Kickstart gear
- flywheel puller


Is there anything that I am missing?

Thanks
@nola_john avatar
UTC

Addicted
GTS, PX125E, P200
Joined: UTC
Posts: 997
Location: New Orleans
 
Addicted
@nola_john avatar
GTS, PX125E, P200
Joined: UTC
Posts: 997
Location: New Orleans
UTC quote
Kick start rubber buffer

You might need the puller tools.
@greasy125 avatar
UTC

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: UTC
Posts: 14899
Location: The state of insanity, SoCal
 
Sergeant at Arms
@greasy125 avatar
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: UTC
Posts: 14899
Location: The state of insanity, SoCal
UTC quote
Mike M wrote:
I've been shopping and I plan on ordering the following for the rebuild:

- PX Seal Set with 30mm rear hub (how do I know if my hub is 30mm)
- PX Gasket set with o rings
- Carb Rebuild Kit with base gaskets
- PX Bearing Set
- Cruciform
- Kickstart gear
- flywheel puller


Is there anything that I am missing?

Thanks
loose rollers for primary
new tab washer for primary
kickstart gear spring
kick start buffers
clutch push pad and pin
clutch plates and brass
clutch castle nut
clutch washer
o-rings for clutch cover
cruciform plunger (they're usually damaged)
order both hub seals*
clutch nut tool
clutch holder
gear shims

the standard P gearbox takes one type of cross, the EFL type take another-- order accordingly.

*look at your rear axle and determine if you've got an EFL style or a standard style-- this takes an entirely different seal than the other two.

if you remove the circlips to pull the piston get new ones

best,
-greasy
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