Modern Vespa

Got heavy handed fitting the clutch side bearing and broke the cases.

Heated case in oven and had bearing in freezer. Used the proper tool from sip. Used the press instead of a hammer for more control, felt some resistance like it was probably seated and then really stupidly give it a little extra squeeze to make sure.

I'd rather abandon the project than start again, but I've spent around a grand on parts for this motor so I guess I need to source another set of px 125/150 cases in the UK. Then go through all of the unseizing, cleaning, port matching etc. again.

ouch.

to prevent that, install the bearing to the point that it clears the case enough to put in the circlip. then use the bearing installation tool to tap both the circlip and bearing into place. The circlip will index into the circlip groove and prevent you from man handling that bearing into the next country.

that being said, if you are going to do it wrong, do it right. time to updade into a set of Malossi cases and shoot for the stars.

I've just been looking at Malossi cases, more than I'd like to spend but it doesn't look like there's any decent PX cases around at least not at an appealing price, £500 px vs £700 Malossi.

I'm tempted to try to get the cases welded, doesn't look like the shape is important just needs to stop the bearing walking out that side.

Is it safe to assume the parts that I've already got would work with Malossi V-One cases?

BGM 177
BGM 57mm crank
BGM Superstrong clutch
All other internal bits from a VNX1M PX 125
Vape for large taper crank
24E or G carbs I've got one of each.

it might the worth the try getting them welded up by a good TIG welder.

PX bottom-end should fit just fine. your new parts will work just fine as well. peronsally, i would would spend the money on new and improved cases before i go with a set of used for not that much less. . . . unless you are looking for model correct.

It's going in a GL that I don't have the original motor for so it won't be model correct either way. With that price gap I also think the Malossi makes more sense.

What makes me wary of running a different brand of engine cases is I couldn't insure my z50 this year due to running a Zongshen motor. It was fine for the last 10+ years but now it's a problem.


I think I'll try to get it welded with Malossi as a plan B.

I feel your pain. It hasn't happened to me…yet, but I've been close. On a Molossi case no less. Thinking the bearing isn't quite seated and giving it a little more. I've been lucky, but not good.

I have made many mistakes on every kind of project. But when you do everything right and it still goes wrong, it's an accident. Accidents, as well as outright stupid mistakes, happen to the best of us.

It was just a little more, just to be sure, trying to do it quickly while there was still a big temperature difference so not wanting to waste time having proper look. The extra force was minimal, but clearly too much.

Found a couple of people that might be able to weld it, one reasonably local. It doesn't need to be pretty it just has to locate the bearing and not interfere with clutch and primary so I'm reasonably hopefully. I'm tempted to get them to add material outside the transfers while they're on so I can open them up a bit more.

Didn't Greasy say that mistakes are opportunities for upgrades?

The Bob Ross of the Vespa world.

If it ain't broke…

Break it trying to fix. Now you know it's broken.

Now you can replace it

This is how it often goes for me.

You could send it to indo for a case refurbishment, they're expats making an honest living. I've literally torn them down to see the marvels and quickly replaced the whole mess with LML, lol.
Upgrade me seeemore!
To unfowl my message, and your regret, remember once you give up and quit, it's a worse remedy trust me. A little sarcasm to save the scoots, and an excuse for a pint.

Lolz! (I may have spit coffee.)

How about drilling and tapping couple holes around the bearing? Then use some red loctite and flanged screws to make sure the bearing stays put.



Less risk for the cases to warp during welding and ending up with oval bearing seat.

Interesting idea, but I'm not sure there's enough material around it for this, I'll take another look at it tonight.

If I were welding it I think I'd leave the bearing in, my thinking is it shields the bearing seat, provides something to build the overhang against, and helps keep it round. I don't know anything about welding aluminium though I only do steel.

If welding it. i would have an old bearing in, an old crank in and cases fully bolted together. Any warping at all, will be a disaster.

However, there's not so much axial force, or those snapped parts would be stronger. I'd do like FINYoshi suggested. Use maybe 5 x M3 screws holding two curved pieces of steel overhaning the bearing.
If it doesn't work....then buy new cases.

There's a repair kit for the earlier cases that's held with two screws, I'm not sure of the screw size but it looks like there's a much bigger flat area available for the screws on those cases.

https://www.sip-scootershop.com/en/product/cluster-circlip-bearing-crankshaft-sip-clutch-side-for-vespa-125-vna-ts-150-vba-t4-160-gs-180-ss-rally-px80-200-pe_87805000


I do have old crank and bearings so I can assemble it to help prevent warping. I don't think it needs the full snapped off area replacing, 3+ shorter welds could do it and would have less warpage risk.

I totally agree and it wouldn't take much. The circlip is just a stop/locator for the bearing. I imagine you could even run it as it is. The only axial force is from the clutch release bushing and that is in the other direction against the seal.
There are three spots at the ribs where you could drill and tap for small screws .

Check this:

Clutch Side Bearing Engine Case Circlip Repair Locking Ring

It's for earlier cases unfortunately, but it does confirm that 2x M5 is adequate.

Those on the previous version of case are M6. I don't think there is enough metal for M5 or 6 but 5 x M3 will easy fit and hold it fine. Couple of bits of steel, red loctite and forget about it.
Will need some careful Dremel work to get the surface level to the bearing face.

When pressed against the case is the bearing tight to the circlip as standard or is there some clearance?

I'm with finyoshi on this - i'd not scrap cases for that, I'd go with what he's proposing

I've decided to try having it welded. Found a tig welder who has done case repairs, going to see what they say.

Around the bearing the case is only 5mm wide so M3 would be the max bolt size. Obviously M3 is M3 but knowing the dimensions and having one in your hand is a bit different, at least it is for me and it didn't fill me with confidence, that's a very small bolt with a very small thread pitch going into such a soft material, then there's a need to flat the area etc. I'm sure everyone's right and it's a viable repair but I think there's a good chance of me screwing it up and I'd prefer to have it welded.

Hope it goes well. I would be inclined to have it welded too if I wanted to keep the case.

Just got it back from the welder. Cost £40

That's great news. I have an old dual port case that looks like it had some welding repairs years ago. Looks to be decent work. Years ago, machinists for these kinds of repairs were easier to find.

Is your bearing seat still round ?

Yes still round no sign of distortion.