Modern Vespa

I was trying to replace variator weights.

I had seen videos of jamming something in rear wheel to loosen rear bolt.

Applying torque to loosen bolt the casting cracked where it holds the brake assembly.

Not good.

Any idea what part I need to replace and how to do it. Suspect I've made a big tedious expensive job out of a small fun one.

Bummer.


Rear casting near handbrake

Front bolt casting cracked also

Looks like the brakes attach to final drive cover, not a common part to find spare.

The engine block and transmission/rear diff are one single casting.

You will need to seek a donor block.

There is no EZ workaround such as patching/welding.

As far as loosening the rear nut, I always put the bike on the ground with tilt lock enable, parking brake set and apply the rear brake lever with a helper loosening the nut.

Replace your final drive cover (OEM code: 8320525) and you'll be fine…

Thanks.
That's what it looked like from what I could see. From manual (2011, bike is 2013) it looked like whole crankcase needs replacement as previous post said.

Ordered a new cover for £200, arriving soon, then found an arm casing on eBay which I bought for £50.

I swapped the variator weights, can't wait to try, a simple job taking minutes if using an impact wrench to loosen nuts instead of cracking casing with a normal wrench.

I would strongly recommend resisting the temptation to run the engine out of idle curiosity before torquing the variator nut, particularly in a crowded yard as it gets dark - the outer variator half can travel a long way when it departs.

Just need to swap cover in the light. Meanwhile here's the bit of aluminum casting that takes all the stress when you use the rear brakes.

In the future, use a piece of velcro or a bungy cord wrapped around the rear brake lever to hold the rear wheel.

zip tie

In fact you don't even need to do that if you use an impact wrench. I was going to but some post said don't, use a breaker bar. Garage I spoke to said he always used one. Even not having a rear brake the clutch nut came off with impact wrench as inertia of rear drive was enough in itself.

yeah but when doing it up again and you want to torque it correctly ...

Yup, will do just that (still waiting for part to finish). You prompted me to re-check the torques. Thanks. Had mis-recalled and done big nut to 80 rather than 160 and was going to do rear to 60 rather than 95 so saved me possible embarrassment!

Last edited by Ilya on Sat, 09 Apr 2022 06:47:01 +0000; edited 1 time

And don't get mixed up with ft-lbs and nm's easy done sometimes.

this is why I wish Robot would stop saying ftlbs in his videos.

It dosen't help when your torque wrench has dual readings and your more used to ftlbs.i'll get used to newton metres just like i have got used to,well almost to the metric system . It's a bit easier than using BSF,whitworth,cycle in all it's different tpi's,BA, unc,unf bsp&t,ME and lots of odd ball specials that turn up sometimes.

You should always consult the shop manual and not take somebody word in a video. Robot has made mistakes multiple times, and corrected later in the video. If youu don't watch the whole video you may not catch the correction, always check the shop manual unless you know what the torque is supposed to be.

So, almost feeling quite pleased with myself, replaced transmission cover, replaced badly scored brake disc, put on new tyre, torqued correctly, loctite, and then discovered this…


Bonus component. Think it goes between brake hub and transmission cover.

For those interested, here is inside of transmission. And how badly scored a disc can get.


Old v new discs

New transmission cover

Cracked brake mountings

Inside final drive

Looks like it goes between wheel and swing arm, that's a lot less hassle, apart from that bloody split pin.

LOCKTITE why ? where? NO locktite, no locktite.

On the little bolts holding the brake disc on.

Many of us have been where you are. Nothing like finishing a job with parts left over.

At least you caught it before you tried to ride it.

Good luck.

Ah, no problem, you do not need to dismount it from the wheel.

ok ok I imagined you locktighting all the bolts on the cover and everything