Modern Vespa

loose bushing crank, fly side. This is supposed to be pressed on with a 1mm gap, using the little flat cut- out tool. This one moves freely up and down the shaft. Any salvage ideas? Or is it new crank time?

60mm time

How sloppy is it? Maybe Loctite 680 would work?

I can move it up and down several MM with one finger.

Is the issue the race or the crank?

You should probably just replace that race along with the bearing since you've put some serious miles on that thing.

That's a good question. I imagine the bushing is more likely to wear than the crank, no?

Yup. I'd assume it's the race unless you're looking for a reason to go crank shopping.

Pretty much anytime i have to split my cases i go ahead and replace the fly side bearing. It's small and prone to wear, and the one in your pic looks to be worn? I would install a new bearing. If the inner race is still sloppy, then you know it's the crank. And if it is the crank, i'd be temped to dimple the crank with a center punch then some locktite.


EDIT: oh wait, it's a stella crank? If it's the original one, consider yourself lucky that it's not worse. Then definitely swap out the crank for a new one.

That's interesting, can you give me more info that?


The PO replaced it before I bought it, so it should have some life left in it. Thanks for the replies!!

Replacing the bearing and race might work as long as you still have a good interference fit. Looking at your photo you can see a line on the crank stub where the race normally sits almost looks like it may have worn. When you get the race off you might be able to determine that.

It's good if the original LML crank was replaced because many have reportedly had big end rod failure.

How does the rod look and feel? Side to side movement is normal push the rod into the big end bearing pin and pull back. If that's got space might be a problem.

How many miles have YOU put on the engine? Is it a modified engine or stock setup?

I've personally put about 7k on it, the PO added the Pinasco 177 and replaced the crank. I was aware of the crank issues when I bought it. They got frustrated I guess, because it was poorly set up. I had to address some air leaks and jetting problems. The bike had about 5300 miles on it when I acquired it, and I think he said he'd put less than 1k on the top-end and crank. It feels fine, no weird play in it, but I was concerned about that wear spot too. I'm probably going to go all- in since it's split. I want to get back on the road, and do not want to repeat this for a few thousand more miles if possible.

That's good does seem like the mileage is low so hopefully everything is fine. Maybe Jack221 can chime in regarding the race issue perhaps it can be bonded if it's not tight with a new one.

Looks like an LML crank to me. So highly likely to be junk. You'll need a new bearing anyway. See how tight that is. Loctite 638 will help but not ideal.

Personally, I'd buy a 60 crank, bearings, seals, cruciform etc. so it went a little better and I wouldn't need to open it again anytime soon.

Cranks seem to be a disposable item on Vespas, particularly if they are from LML. I wouldn't go through the trouble of splitting the case and reinstalling a crank unless you could install a new race on it without any fuckery involved.

Make your precious time count by installing a known good part so you don't have to do it again when whatever snot you use to hold the race on let's go.

Well, that settles that.

If I go 60, aside from a base packer, would I get into port work etc.? I like the way it ran before this issue, but if for a little more $$ I can get better, low effort performance, I'm game. Would the long crank benefit me without port work?

This, 100%.

No, you don't have to do any porting. Get a flowed 60mm like this one with 1.5mm base and head spacers. You can also tune your squish to right where you want it since you'll have the room to adjust on top if you want to (I would...but we know I have "issues" about that sort of thing).

You'll get a more torque in the mid-range and a little higher peak power. You gotta put a kit on tha' bitch to really change the performance, though.

Thanks. I have a Pinasco aluminum kit on it now. If I can get a little gain for just a few bucks more, seems like a no- brainer. Before the reed incident, I could hit about 63mph GPS at 6500RPM's and not be absolutely screaming. A little extra mid range torque and peak power might be nice. I ride every dry day after work, usually about 30-50 miles, and it sucks to have her in pieces.

I think he said it had a Pinasco 177.

The Pinasco will pair well with a 60mm crank.

I had a similar setup in cast iron on my Sprint for a while (extended intake rotary, not reed) and it was super solid other than a seize when one of the cylinder studs came loose on the highway. I still managed to ride it 15 miles home, albeit very nervously.