Modern Vespa

Hi all. I was attempting to change out my belt and rollers, about 3000 miles past due. I had read through the couple of different procedures on here and felt comfortable tackling this for the first time.

But now I've broken the 10mm section off of the driven pulley. I attempted to break the 21mm nut loose use the method described byBubbaJohn I believe, but with the parking brake engaged and holding the rear brake the tire would still slip and spin while trying to undo the nut. I then tried the method of a breaker bar on the 10mm section and a deep-offset 21mm wrench. I had to lean on the back of the bike to prevent picking the whole bike up and then the 10mm section ripped off.

So, aside from the horrible feeling I have now. What should I do? I kinda hate to take it to the local shop, as they are the ones that replaced the belt last time, along with a rebuild of the the rear gear that cost me over $900. And when I tried working on this last weekend found that one of the bolts to my rear brake caliper was missing, presumable not re-installed when they last did work. They also used a power drill on the air filter cover screws and caused the plastic to drill out. I watched them do that, and now I have had to go up a screw size to get the air filter secure.

Don't worry about that 10mm bit - it's useless as you've found out.

Jam on the back brake with zip-ties, use the parking brake, and you might need a stout wood chock through the spokes as well. I bet the shop did up the nut with an air impact wrench with not much regard to getting anywhere near the specified torque settings (which aren't that great as is happens). When the correct torque is used, zip-ties on the back brake do the job just fine.

Yep, I agree with Jim. Just stick an axe handle or something like that through the wheel to hold it. Make sure you do that somewhere that when it's under pressure, it's not trying to bend something important like brake lines...

I've always had to use an impact wrench to remove the back nut, even though I put it on with a torque wrench. It's quite a tough bugger...

Mark

Jimc is correct that you are not screwed. You just can't use Piaggio's recommended method.

When you used the deep offset and 10mm socket, were you turning the 10mm clockwise our counterclockwise?

Being a minimal mechanic one need not go into debt buying quality metric offset box wrench set for a once awhile usage. An alternative source is to use a 13/16 SAE offset box wrench. The least expensive set is available at http://www.harborfreight.com/hand-tools/wrenches/8-piece-sae-offset-box-wrench-set-32041.html their metric set skips 21mm. It only needs to hold up for several belt changes to pay for it self.
Although it's much better for the bolts to use the proper corresponding wrench, there are some quick conversions between the metric and SAE standards that will work in a pinch. If you find yourself with one stubborn Metric bolt when you only have SAE wrenches, or vice versa, you can use these approximate conversions from millimeters to inches:
8mm - 5/16
13mm - 1/2
14mm - 9/16
15mm - 5/8
19mm - 3/4
21mm - 13/16
22mm- 7/8

Chuck the 10mm stub your better off without it.

GOOD GAWD NO!!!

Use Metric on your bike and SAE on someone else's. Some of the nuts you'll be accessing during regular maintenance is made of cast iron, which tends to be soft. Using the wrong sized wrench/socket can round the corners, meaning eventually that same wrench socket will no longer work; nor will any other tool. Using a 12 point will just speed up the stripping process.

If you want to save money by doing the work yourself, justify it to yourself by spending the funds you would have paid a shop on THE PROPER TOOLS for the first time. If it's not a tight quarters space, go for 6 point.

Keep in mind that this is coming from an ultra-frugal person. I love Harbor Freight (but I'm very selective about which tools I buy from them).

That being said, you can use an impact driver to get the driven nut off. The easiest method is to take the bike off the center stand (super easy since it's an MP3 with that fancy tilt-lock business up front) and use an impact driver (with an impact rated 6 point socket) on the nut you're having problems with.

For re-torquing, Look into some torque limiting extensions. Harbor Freight has some (and they work quite well) but you might feel safer with a more standard brand. In either case, I think this will be your best option outside of replacing some major drive-train parts. I use these, and have double checked with a bar style torque wrench and it's always in spec. Put the parking brake on and squeeze the rear brake. I wouldn't worry about an axe handle or 2x4. That's just odd and potentially destructive towards the axe or the rims/brakes (potential damage to the brakes serving as a red flag here).

Hope that helps. Please use your common sense and ask if you have unanswered questions.

Right on Cagedodger.
There is no fault in your statement and spot on with additional wisdom. Unless like me, living in a area of very limited resources and downtime is critical, then making due with what is available is necessary. I should have stated that more clearly in my post.

Greetings from Hayseed U.S.A.

I was turning the 10mm CW and the 21mm CCW, as seemed to be indicated by the threads as well as the video in http://www.scooterrific.net/belt.pdf

Went and borrowed an air compressor last night and have tried to use an impact wrench on it, and it is not moving

Tried using the torque wrench (I know I shouldn't use it as a breaker bar, but it is the only one I have with a 1/2 inch drive) and even with the parking brake on, the rear brake handle zip tied down, and the scooter off of its center stand, the only thing that accomplished was moving the scooter forward in very small increments.

Jam a bit of wood through the wheel (noting caveats above), use a breaker bar with a 'welly magnifier' - aka a bit of steel scaffold pole to give much greater mechanical advantage.

Once it's off this time you should be golden in the future as long as you don't let that shop near it again.

Recommendations on where to jam the wood through?

I tried that last week and ended up knocking the parking brake caliper out of alignment, resulting in the caliper hitting the spokes of the rear wheel when I went for a test ride.
Had to take off the muffler and rear tire to find out what was going on. That is when I discovered the missing bolt on the rear brake caliper.

So I'm hesitant about this method, but trust your opinion jimc. If I do this, where is the best place for the wood?

your in ATL ride it over to the guys at Motoretta and let them do it for you.

I've moved to the top end of Atlanta, so that is a 26 mile ride.
My MP3 is my only ride, so if they want it for an overnighter, I will need to get my girlfriend to pick me up and take me back down, etc.
Also, I'm a college student, so funds are very tight.
I am studying Mechatronics Engineering, so should be comfortable with doing my own mechanical work.
The guys I took it to last time "Marietta Sportscar / Vespa Marietta" are made up of some of the same techs from the previous "Scooter Superstores of America / Vespa Midtown". I believe some of the other techs from that store went to Motoretta when Scooter Superstores shut down.

I will take it to them if I have to, but kinda sucks after spending the money on the tools and parts, just to wimp out and take it to another shop.

you could always ride up to "The Barn" it should only take you 3.6 hrs each way.

Call the Marietta guys and see if they can just loosen it for you then firm it back but not so tight till you get home.

Jam the bit of wood where it won't bend anything, that's all.

Or ride down the 26 miles (that's hardly far!), get them to undo it, then do it up again yourself to the right torque. Ride home, get the job done at your leisure. Or get any tyre place to undo it wit their impact gun.

So many options!

Go the the Barn, think of it as a field trip with benefits to boot.

I didn't mean to jump on you there (afterwards it reads a little harsher than intended) as your advice is good in a pinch, especially with the approximations. If in a pinch, your advice would work, but if he's got the option to get the right tools, the right tools should be used.

Salutations from The City, U.S.A

Agree👍

I think you've created the 1st MP3 fishing weight?

Re: manual rear wheel lock; a wrecking bar or tire iron slid into a section of 1/2" PVC irrigation pipe worked well to protect from damage as I slid it into position between spokes, careful not to rest against brake linkage, etc. causing potential damage.

Re: repairing stripped threads on black plastic of air filter; partially fill hole with black RTV, you can use toothpick; apply thin film of petroleum jelly all over screw(s) (make sure screw has nice sheen all over but no globs); push screw all the way into hole (without filter cover), some RTV may ooze out, don't worry you can trim and clean up after RTV has set; after RTV has set (overnight) unscrew screw and trim off any access.

I didn't notice this being mentioned, so I'll ask - could a good overnight soak with Liquid Wrench help?

When I had trouble with the nut on the muffler side, I sprayed a bunch of solvents on it and couldn't get it to come loose. Until I rode about 60 miles. The next time I tried, it came off with just a hand wrench...

All that to say, you may need to not just spray on a solvent, but also ride a bit to work it loose.

Liquid wrench overnight. Then quick application of high heat to the nut only. Small butane pinpoint torch, just enough for the nut to get hot, then quick on the wrench with wheel very well locked, as stated here by others. Should break loose.

Get a stronger impact gun! It will do it!

Cagedodger, your point about using the correct size wrench is good as a general principle ... except 13/16" = 20.6375mm, very slightly less than 21 mm. So if the 13/16" wrench fits over the 21mm nut head (which it will), you can be confident that the wrench won't round off the nut-especially if the wrench is a six-point, which I highly recommend.

Also, 3/4" is so close to 19mm (it converts to 19.05), there's no reason not to substitute a 3/4" if you don't have a 19. In fact many metric wrench sets omit 19mm on the theory that people already have a 3/4".

The same for 5/8 to 16mm. Conversion links:
Technical- http://www.engineeringtoolbox.com/inches-mm-conversion-d_751.html
Simple- http://www.highlandlighting.com/conversion.htm

I use a deep offset 13/16 for the clutch nut, never any issues.

Huh? Many? Not the ones I've seen in the US (I assume you meant 'many in the US')...

Yep, I meant "many in the U.S." I haven't made a study of it, but of the metric wrench sets (of various types) I've purchased, most lacked a 19mm. I could see the situation being different in Europe, where it would be unrealistic to expect people to have 3/4" wrenches already.

Anyway, I'm very glad to see that that little center bit isn't crucial. Mine hasn't broken yet, but it has given me anxiety when I torqued it after a belt change.

the low down on the clutch nut.

Hold the 10mm with a breaker bar that is long enough to reach the ground/floor. loosen the 21mm nut.

when reinstalling just the opposite.

hold the 21mm nut and reverse torque the 10mm shaft to spec.

And there's me having taken off the clutch nut countless times on 500's from back in 2005, and I've never ever considered using that 10mm 'end'. I mean - why? You need an extra tool that's got no other sensible use, and the torque doing it up is less than the back brake can hold.

Only extra tool needed is a $10 offset wrench and for me I find it easier than messing with the brake while applying torque. The brake will hold but takes a very strong squeeze of the lever at the torque specified in the manual.

Both methods work and no need to get in a pissing contest as to which is better. Use the one that works for you but don't bash people that prefer the other.

Didn't seem like bashing to me.

I managed to get it loose this morning. I sprayed the nut down with Liquid Wrench last night when I got home from school. This morning I wheeled it around to my work pad. I put on the parking brake, zip-tied the rear brake, and tried the impact wrench and the torque wrench with no luck. The wheel still continued to turn before the nut did.

Then I got out a hammer And inserted it into the rear tire (see the picture) up against the shocks. Then I pulled with the torque wrench and finally it came loose.

But look what it did to my hammer before it came loose.

way over torqued

Cheap-ass hammer!

a HF special you say.

I've had that hammer for nearly 20 years. It is solid. Now it has an "improved ergonomic grip that places the head directly in front of you while your arm is off to the side a bit". First prototype of my new ergonomic hammer is being sold for only $49.95, who wants one? 8)
I think I'm on my way to making a fortune.

I also finished up changing out the belt and roller. Thanks everyone for your help, advice, and smart-ass comments.

Wow! Glad you were able to remove it eventually.

If you're friends with the service guys at the shop that did the work before, I'd take the hammer in to show them how badly the over tightened it...

Mark

That explains it. The thing was wore out and bound to fail.

I'll take one, you can send me the $49.95 thru paypal for taking this off your hands.

I think I'll have to put something in my how-to that if the nut doesn't come off easy - use an impact wrench.
Just take it down to a garage, pull the cover, let them remove the bolt, then re-torque and drive it home to change the belt.