Modern Vespa

So, I'm having new tires put on my 2011 GTV, and when I removed the rear swingarm to remove the rear wheel, I noticed that the main bearing is feeling gritty.

I don't have a bearing press in the garage, but I figured I'd go caveman-style as my dad and I used to do when rebuilding engines back in the 70's. I'll get a torch, heat up the swingarm, and pound it outta there. That'll probably do for removal, as it won't matter if I screw up the bearing getting it out.

I'm going to have to find a suitable drift to drive it back in, though. I suppose I'll give it a try first to see how badly I can screw it up...haha.

Anyone else done this as a home repair? At least the bearings are cheap - $8.95 from Scooterwest. I figured it's inexpensive enough to take a shot, anyway...

Robot has a video on how to do it with just basic tools:

https://youtu.be/14DE8a2mBfM

Well, that was handy. It's pretty much exactly how I was going to do it. I was just in the garage grinding down an old piece of well pipe to use as a drift. Looks pretty straightforward...

In the years I've ben a tech I've rarely ever had to use a bearing puller or flame. Just a heat gun (not a hair dryer, but even that can help). Using a flame to heat things up can be ok but it's not the way modern techs over here do it in case of damage and other health and safety laws over here. So just the heat gun. The bearing will virtually fall out with little force if you do it this way. Even gearbox bearings just pop out with rapid heating of the casing around the bearing and a gloved finger or slight pressure from a screwdriver.

We tend to put the new bearing in the freezer for a few hours before fitting and make sure to heat up the swing arm again before just popping the new bearing back in. It works and no real force is needed to do this. Good luck!

That bearing on my scoot, which had been treated neglectfully by a PO, was badly corroded in the aluminum casting. Heat and penetrating oil had absolutely no effect. It had to be sectioned out with a Dremel after the inner race and bearings departed the premises. Even the circlip had to be broken out in pieces. Robot had made it look so easy! But that's Hollywood for ya, I guess.

Finding an acceptable replacement bearing was a bit of a challenge - there are a lot of cheap Chinese bearings sold on Amazon that are misrepresented as being Japanese in origin. Maybe they're good enough, but I'd put so much time into removing the old one that I wanted a verifiably good one in there!

To press the bearing back in I used a threaded rod with nuts on either side, a very short section of pipe just a hair narrower than the outer diameter of the bearing's outer race, and a stack of large washers. The rod and nuts squeezed the washers against the pipe, which forced the bearing into the hole. It was relatively simple to keep the rod perpendicular to the swingarm so the bearing went in squarely. I can't remember why I didn't just pound the bearing back in.

The circlips are an unusually large metric size, but were easily sourced from McMaster. I am now the proud owner of 9 extra circlips of the size in Robot's video, if anybody needs one.

(Front bearings were much easier - a $50 blind bearing puller set from Amazon was quite helpful and quite worth the money.)

Huh - there's no circlip on the rear swingarm bearing in my 2011 GTV. Hopefully the bearing will pound out easily. Unfortunately, I can't seem to find any place with a propane torch in town. Hardware store guy says supply lines are sketchy right now... I just ordered one of the Chinese bearings from Scooterwest. The SKF oem bearing was like $30, so I figured for nine bucks I'd try it out and see how long the cheap one lasts.


Cheers.

Cool, thanks. I'm hoping it goes smoothly. I should get the replacement bearing in the mail soon, so we'll see how it goes! Didn't think to freeze the replacement bearing, but I suppose it's easy enough to do. Maybe it'll just slide in there!

Thanks for sharing your experience. It's always helpful to hear from folks who've done it before...

Yes, the bearing will virtually just drop in if you use a heat gun on the swing arm (exhaust carrier), get it nice and hot. Then the very cold bearing (that you can leave in the freezer overnight) will virtually just drop straight in with a tap or two to get it fully home using a drift (a large socket on the outer bearing race can do it), but rarely any real force needed if you work quickly while the bearing is still cold and the arm still nice and hot. You can use a very very thin smear of lithium grease on the inside of the bearing housing. But it must only be the very slightest amount to avoid hydraulic lock with grease build up at the bottom of the bearing housing as the bearing is pushed in.

The important thing about removing the bearing is to get the swing arm hot very quickly. That's why a heat gun works so well. A flame can do the same thing but isn't actually necessary. It doesn't do anything a heat gun won't do. You'll find it an easy job I'm sure. Again, good luck!

New Bearings of whatever size generally have the correct amount of grease for a spinning bearing at a slightly elevated temperature
The manufacturer wants to avoid complaints when a brand new bearing under normal operating condition, puking some grease out

I don't have this specific bike judging by the appearance, this is a large bearing that doesn't spin all the way around

Before I replaced it I would stick a grease needle past the seal/shield & fill it with grease, or remove one seal/shield, clean & regrease

If I where replacing the bearing I would pack it full with waterproof wheel bearing grease

Huh? This bearing carries the rear axle. Of course it spins all the way round!

Thanks
misread the op :O

I'm not talking about putting grease in the bearing, just on the inside of the bearing housing to help the bearing slip nicely in without any real pressure. It's standard practice over here. Afterwards as the swing arm cools it grips the bearing very tightly.

Well, I managed to get it all zipped up today. The bearing came a day early, so I was able to give it the 'ol Hulk SMASH and get the bearing out of the swingarm, and the new one back in. I had to use a butane torch, as none of the hardware stores in town had a propane torch. I actually ended up buying it at a vape shop in Mammoth. Boy, I haven't been in a 'head shop' since I lived in San Francisco back in college. They haven't changed much. And they had about a hundred different butane torches to choose from.

Anyway, I got the swingarm heated up just fine. I ground down a piece of well pipe I had laying around to use as a drift. While the bearing came out easily, it took some real hits to get it driven down into the swingarm. I actually used a bench vise to get it started. Once I got past the first 1/8" or so, it was fine.

Changed the oil while I had the GTV up on the stand and could flip up the center stand outta the way. Started right back up, so I guess we'll see how many miles I can get out of the new bearing. New tires, oil change, new filter, new rear bearing - now I just wish the temperature would drop below 95deg F so it's more comfortable to ride!

Thanks for the help, all.

I am aVespa owner but mainly work on BMW bikes. All the bearings in the various parts of a BMW need to have their mounting housing heated to expand so you can knock out the bearing without damaging the bore the bearing fits into. I have used heat guns, carefully added propane torch and now think these little steam pots that are available might be a good fall back as they carry lots of thermal energy. Last time I tried to heat up a front wheel bearing bore on a BMW wheel it took a half hour as the surrounding aluminum sucked the heat. Some folks recommend pouring boiling water over said casting. The jist of it is heat it up seriously. Same when you are ready to press in the new bearing by pushing on the outer rim.

Fully agree beech. If a bearing isn't going in easy, the housing is not hot enough.

To biffnix, WELL DONE! Excellent work. Enjoy your bike. You've just saved yourself a ton of money and got your bike back to excellent shape. Thanks for posting about this, it always helps others too.

Three issues with adding grease to a pre-greased sealed bearing:
1. Damage to the seal.
2. Grease compatibility with the grease that's already in there.
3. The manufacturer doesn't refrain from pack the bearing full because they are cheap or don't want people to complain about the mess. It's because too much grease can work out of the seals and gather dirt, which could then damage the seals. Also, excess grease can cause added friction, and heat, which can then degrade the grease.

Don't get me wrong, when I repack bicycle wheel bearings or bottom brackets, they are swimming in grease. But in those cases there aren't seals to worry about (not in the same way, at the least). And those rebuilds are well cleaned prior to packing, so no incompatibility to worry about either. And it's a lower heat/lower stress sort of situation.

Very True Madison, about the compatibility of different greases.

Folks often make the mistake of putting in more grease to a bearing without thought to this subject. There are at least 12 different grease types that come to mind that are not compatible. Mixing soap and clay greases is not a good idea, or any of the synthetic greases. And how does anyone know what grease has been put into a bearing at the factory! Short of testing the grease in a lab it's difficult to tell. So actually adding grease can in fact shorten the bearings life considerably.