Modern Vespa

Hi everyone,

I am getting a rubbing noise when I release the clutch and I'm accelerating. Happens in every gear. It's kind of like and RRRR sound in case the link doesn't work. As I accelerate, it stops.

When I release the clutch and I'm coasting, the bike stuttered or jerked a little as it slowed. As if there's some internal resistance. Anyway, once it did that, I took it off the road.

I know I am probably going to have to drop the engine. Any ideas where to start?

1962 Vespa VNB

Jim

Welcome to MV! We'll get you sorted out in short order, I'm sure.

Also, thanks for sharing a video with your question, because it saves me having to ask!

Just to confirm...it only does it in gear. So that means something rubbing related to the wheel, gearbox, or clutch.

Good news is that only one of those three things requires cracking the cases (a gearbox issue) and I don't think it's that. The rest you can probably check with the motor in the bike.

A few more questions to complete your Intake Questionnaire:

- Is this scoot new to you, or has it run without issues for a while?
- Have you made any changes to the scoot before this started?
- Has it developed any leaks?
- What's your mechanical comfort level? (So we know how explicit to make our guidance)

First off, I'd also make sure it's not something really simple like the rear tire rubbing on the clutch cover. Just remove the wheel and look for signs of rubbing.

Then, I'd get the rear wheel off the ground and in Neutral, but not running. Rotate the rear wheel by hand and determine what, if anything, you can hear.

If it's in the gearbox, you'll hear the whining sound, but that doesn't sound like the gearbox to me, so we can return to that down the road.

If it's not in the gearbox, you're probably looking at something on the clutch. Good news there is that you don't need to drop the motor to get at it. Just remove the rear wheel and you can get to the clutch. This would be consistent with jerkiness, though the whining is a bit of a mystery still.

It'll be easier to access the clutch if you can lay the bike over (probably want to remove the gas tank or have it less than 1/2 full for this) so you can both see what you're doing and also not by lying on the ground working over your head.

One final note, you're almost certainly going to need a clutch castle nut tool to remove the clutch, so either order/borrow one up front or be ready to have the bike open for a few days until you can get one.

And, again, Welcome to the Dark Side!

Thank you for your reply. Very helpful.

Is this scoot new to you, or has it run without issues for a while?

The engine was rebuilt 20+ years ago and was crated. when I rebuilt the scoot, I decided to just place the engine back in. I replaced the carb and crank case oil. The seals and any interior work is as it was from 20 years ago.

Have you made any changes to the scoot before this started?

Just what I noted above. Except for the engine, I replaced everything - cables, electrical, bearings etc.

Has it developed any leaks?

I get a little leak from case.

What's your mechanical comfort level? (So we know how explicit to make our guidance)

I can do pretty much anything.

I forgot to mention that when the noise is happening, once I engage the clutch, it stops. Thanks again for all of this detail. I was going to sell after rebuilding it but once it fired up, I knew I wasn't letting it go. Thanks again!

Okay...so twenty-year old crate motor...hmmm...dry seal, maybe, but I'd expect that to sort itself out pretty quickly.

Go ahead and run the tests I suggested above to see if you can isolate the source of the rubbing and then we can go from there.

You really shouldn't need to, but have you checked that the vice grips are still in your toolbox? I had very similar symptoms last weekend.


[/img]

Maybe this ?

?si=ILEc4uvEYROJiB84

I still haven't figured out how you managed that, but it makes me feel a lot better about the time I somehow got an 11mm wrench stuck inside my flwheel cover and rode around with it that way.

I know I've left tools clamped to my bus and driven many miles.

My worst self inflected breakdown (bus) happened when I forgot to tighten the bracket that held the ignition coil. It fell off and the cooling fan mauled the ignition wires. Had to get towed off the 401 in Toronto.

Yeah no stuck tools, wheel doesn't seem to be rubbing. It spins freely in neutral.

Just the Jetsons sound without the cool benefit of air travel.

Sounds like gear noise to me but that's just a guess. I have heard a sound like that from scooters with gears swapped out from other scooters or have been run without oil. Mixing and matching used gears is a crap shoot. If the gears have been "bed-in" in different engines its hard to mix them and keep things quiet. It can been done but...

I would look at the primary drive gears on the clutch and the cush gear on the tree. Clutch drive alignment? That would make sense because its happening in every gear and under load, right?

At the three second mark in the video just as you push the bike off the stand, it makes a chirp that's almost the same tone as the squeak when you pull away. Did you pull in the clutch before you pushed it off the stand?

(I'm starting to lean toward something clutch-related, but don't have a good working theory yet)

The fact that the bike jerks a little when coasting - imagine you're coasting and someone mule kicked the floor brake briefly - makes me think it might be the clutch or gears.

That little chirp is just the stand spring. I think. Now I have to double check. Good ear.