Modern Vespa

Disclaimer: no one was physically injured. (Emotionally, now...)

Started a 9 day road trip with the husband and kids, from the Bay area CA to Mount Humbug in OR and back. Him on the xmax, with kid#1 on the back, me with kid #2 on my GTS. Day 1 went perfectly. Day 2 started well, but about 30 minutes outside Fort Ross, my rear wheel suddenly started going crunch crunch crunch. Pulled over fast.

Got it towed to the local yard (Occidental Towing in Camp Meeker - if you're ever having a bad day near there, call them!!) Got a car rental, drove the kids and clothes/top boxes home.

Next day (yesterday), rented a trailer from u haul (10/10, will do again if we need to move a bike) and drive up and back to bring my scoot home again.

We suspect it's the rear wheel bearing. (There's a story behind why it wasn't changed with the last tire change, but I won't bore you further.) Going to take the back end apart today to inspect everything, and see what we need to order to get things running again.

Anyone want to guess at the final diagnosis? Just for funsies. The only thing you can win here are my tears, some dirt, and a whole lot of cussing...

Glad that everyone was okay. Got nervous when saw the thread header.

Based on what you said, and that the tire was not flat, a loud crunch could definitely be the bearing.

Tire was definitely not flat. Was not the rear break. Engine runs fine. Put it up on the center stand, revved the engine slightly, and the back wheel did turn, so it's not the belts. But it is stiff when trying to wheel it.

So I'm pretty sure it's the wheel bearing. My big question is how badly did I mess up the mechanisms. Do I just need to replace the bearing? Or am I going to have to replace everything including the axle? Or somewhere in-between...[/quote]

hard to make a decent guess with out pics and video with audio.

bearing is probably a decent guess and why could be spacers not installed correctly from last tire change.

So, not the bearing on the right side of the wheel. Checked it, and it feels good. (Going to replace it anyway.)

Took the wheel off. Spun the disk thingie. Still grinding.

Next step is to look inside the drive area, but new suspicion is a bearing inside the hub.

Picture attached of what I think I need to somehow remove next. Video maybe later.

Any tips on how to get the hub off/open it up to check?

that whole disc assy should slide off. if stuck you might try a 3 jaw puller.

also robot at scooter west might have a video on it

It did just slide right off!

Pics from inside.

Not seeing anything that would cause the crunching sounds?

So need to continue working my way 'left'. Time to peruse Robot's videos more...

I don't know but that axle in between the thread on the right and the splines on the left look awful. It should be a perfectly machined cylindrical axle.

Yeah, that's fingerprints in antiseize. Husband grabbed it to try and turn it, to see if it was still sounding cruncy. Unsurprisngly, it didn't turn.

And I made him go wash that stuff off his hands asap. That stuff is no good for bare skin.

That part of the axle is actually smooth. I'm concerned about damage to the splines. Need to take a closer look at them to make sure they're good, when I go back out.

splines look ok.

If its not turning the bearing in the gear housing could be bad.

also pull the cover off the variator clutch side and give that side a good look see.

There are a lot more bearings to check on the other side (CVT cover, driven pulley, gearbox)...

I'm guessing this bearing was a significant part of the problem 😂

After removing the cover: the culprit!

... I'm pretty sure the balls weren't supposed to scatter over the garage floor when I removed the cover...

Looks like you lucked out, no bearing failure inside the final drive. Probably want to pop the cover and take a look while you have it apart though. And maybe replace the other bearing and seal for the clutch shaft. Page 12 items 7 and 8. Final drive on page 27.

https://www.af1racing.com/ProdImages/st3/EVGP000US9.pdf

yup that would be a bearing failure.

pondering about why the bearing failed ... do you use an impact gun or a torque wrench?

is the washer missing behind the nut? if so that would have caused the bearing failure.

Nope, hand tools and then torque to specs. And I'm female, so none of this excessive strength thing going on to overtighten stuff. Nope. Got the parts. I'm pretty obsessive about keeping the parts together!

I suspect, just bad luck and hard riding. It's at about 20,000 miles, and was good at 18,000 when I changed the belt. Also, reflecting back, I'd been seeing some mild drop in performance (slightly lowered gas milage, harder to hit higher speeds) which were probably early warning signs. I had chalked it up to taking my teen to/from school everyday, but it was probably the bearing. Plus, I'd just ridden it about 150 miles the day before, a good chunk at freeway speed.

you changed the belt at 18k and then had a bearing failure 2k after. During that 2k reduced gas mileage and reduced performance. this tells me it was not reassembled correctly after the belt change.

This bearing does not fail with out a cause. plenty of scoots with 30-40-50k on them original bearing.

it could be a simple as assemble in the wrong order thus causing over torqued on the nut which puts too much pressure n the bearing and the failure.

That's what happened to my on my Scarabeo. After I replaced the rear tire at about 16k miles, the 13-year-old bearing went gnarly after about 1500 additional miles. I'm pretty sure I had reassembled the washer in the wrong order, but I'm not positive - the front bearing had also recently gone bad, due to age and harsh treatment by a PO.

Perhaps you've solved this already, but the bearings and retaining circlip (if relevant on your setup) were far less expensive and far easier to locate outside of the Piaggio parts system. I used Timken bearings and a circlip from McMaster.com.

Thank you. I'm not as concerned about cost as speed. Scooterwest informs me that the bearing is on back order, and it will be 2-3 weeks before they have it in stock. I'm not fond of the idea of driving our PCX instead for that time! It's better than a car, but... It's not my Vespa!


It's certainly possible that I reassembled it wrong - it was my first time changing a belt, and it took me about 12 hours for the whole service (in one day!!). At that point, errors are bound to creep in.

I did notice the reduced performance after the belt change, but it wasn't an *always* reduced... Just a 'didnt leave the intersection quite as jumpy as before' kind of a thing. I could still reach 45-50ish (local speed limited in my commute) in a more than reasonable amount of time, and never needed to pin it until this past weekend (to hit 76 on 101 - again, carrying about 280ish lb of people plus gear going uphill.) So, again, I just attributed it to having extra weight on the bike.

My husband notes that after the previous service (done by San Jose BMW, where we bought the GTS) but before the one I did, he was hearing a quieter squeaking on the back wheel whenever we backed it up. But that could also be attributed to many other things.

Also, I checked my records, and the 2-3 mpg drop in gas happened in August, before I changed the belts - so it likely WAS due to adding an extra 150ish lbs to my drive. (Teen + their backpack). I changed the belts/did the 18000 service in October. I was getting in the low 60s before adding the kid, and high 50s after, where it stayed until this past weekend when it dropped to 57mpg.[/quote]

Did you see if scooterpartsco.com has the part in stock?

If you Google around you can find out the dimensions of that bearing and order it from any number of industrial supply shops or even Amazon, which is where I got mine. I see they're listed on Amazon at $15 for a pair delivered tomorrow via Amazon Prime. (Edit: and I see ScooterPartsCo has several versions in stock for a bit less if you only need one. Bearings are sometimes counterfeited, and I would go with Scooterpartsco's over Amazon.)

My 500cc scooter bearing turns out to be the same as the one used for 150ccs, so maybe Piaggio uses the same ones on all of their scooters? It was part number Piaggio 82545R (equivalent to Piaggio 826974, 432305), and its size is 17x47x14 in millimeters. I believe that's inner hole diameter ("bore") x outer bearing diameter x thickness. Its spec was 6303-2RS.

About that spec…I learned that bearing codes mean the following:
6=single row deep groove
2 or 3 = series, aka durability, 2=light, 3=medium
01=13mm bore, 02=15mm bore, 03=17mm bore
"2RS" and "DDU" is typical for scooters and means "rubber seal on both sides", "ZZ" is metal double shielded, "2NSE" is nitrile shielded on both sides of bearing with a lip on both inner and outer radii.

You did it right, these bearings fail because they are shielded not sealed from the factory. I had to replace one at less than 10k because I used Simple Green and water to clean the cover and got water in the bearing.

This is one I would not replace with the factory part, it will be shield type as well. As detailed above you want a 2RS type with rubber seal on both sides like this one:

https://scooterpartsco.com/gts-300-drive-and-transmission-c-3637_3643_3802/stainless-steel-variator-cover-bearing-p-10410.html

Reading this thread tells me that bearing's not the only thing with (virtual) balls! Good for you for conceiving and undertaking such an adventure, with kids, no less. Ride on, strong lady.

Bike is all better now

So, to summarize:
Had a bad bearing in the transmission case. About as bad as a bearing can get.

Had to buy a new bearing (thanks for the tip about timkin) from Amazon, as scooterwest still doesn't have it in stock.

Had to buy a circlip tool (but was able to reuse the old circlip.)

Had to buy a large socket the size of the bearing to install the bearing, and a slightly smaller socket to get the old one's remaining piece out.

After reading old modern Vespa posts, I heated the transmission cover in the oven to 300 - and was able to easily pop the outer race out of the cover. Two days later, my new bearing arrived, and I froze it. Then reheated the cover, popped the bearing out of the freezer, where it dropped in about 90% of the way. A single tap with the new socket, and it dropped in the rest of the way. Let everything cool down, then reassembled (watching the tail end of Robot's 6k service video on .75 speed to make sure I reassembled everything properly.

Then replaced the tone ring my husband busted, and reinstalled the rear wheel.

Took it for a short ride to reset the ASR, then a longer ride (including some freeway time) just to make sure everything was running well.

Felt good to be back on my baby again! Looking forward to riding MY bike next week, instead of my kid's PCX.

Total cost for repairs: $60, some bad language, and a few hours.

... And I have not learned my lesson. We're planning on trying to do the trip again in June

Well done! Thanks for taking the time to document here!