Modern Vespa

2003 ET4
So it started as a standard belt change - bought the kit from ScooterWest - cleaned everything and changed the rollers, ramp glides, belt and lock nut. Put it all back together and started it only to hear a horrendous noise (recording available but I can not upload?).
Fast forward to multiple times pulling apart and putting back together including putting old parts back in and still....the same horrible noise - hard to tell where it is coming from.
For the moment, and while working on it only, we are using the same lock nut - have another on order but I can't believe all that noise could be coming from there.
Finally able to upload sound at: https://freesound.org/people/taralynnc/sounds/586845/
Does anyone see/hear anything we are missing?



















Last edited by taralynnc on Tue, 14 Sep 2021 00:10:31 +0000; edited 1 time

the nut holding the clutch on the shaft was on there before the first pic, right?

Better still by far - the transmission cover was back and buttoned up when you tried to run the engine?

Was the cover on the transmission?

Yes to all - everything was buttoned up for sure!

Maybe you can describe the noise. Rattling? Squeaking? Scraping? Squealing? Thumping? Clanking? …
High or low pitched?
…?

You're sure it isn't exhaust noise?

Sure - somewhat of a high pitched whine/screech. At first we thought grinding but no, sounds like a screech. Seems the same pitch as it is idling and while giving it gas - maybe a bit accelerated with gas. Should not be exhaust - didn't do a thing with that.

Last edited by taralynnc on Sun, 12 Sep 2021 20:59:36 +0000; edited 1 time

When it's only idling, can you stop the rear wheel (if it's spinning)? So the final drive gears aren't turning — the whine isn't coming from there?

I can't see anything in the photos that looks wrong.

Thanks for the review - it is driving us crazy - have taken it apart and back together multiple times! Yes we can stop the wheel so the rear drive is not spinning and no, the noise is not coming from there.

Well, I don't have an ET4 but it looks very similar to my Primavera and I don't see anything obviously out of place.

Thanks - yes, my husband has an LX and we did his belt literally 1 hour prior with no issues.

Are you getting the variator nut all the way on and torqued to spec? That can be a bit hard to do because the belt has to ride up the variator pulley a bit before the variator's tight.

Sure did - multiple times - 61 lbs ea time. I know it is a one time use but we've literally taken it apart so many times that we had to use the same nut until we are reasonably sure that all is OK. At first we thought maybe belt was pinched but have since ruled that out.

See any rubbing or scraping inside the cover?

negative

That's all I can think of for now.

This is a blind guess because it's been years since I owned a ET4. That model has a kick starter mounted to the cover, right? I had a couple problems with mine because a previous owner monkeyed around with it. I never could get the kick start to work right and it would occasionally hang up and scrape against the variator. I ended up just taking the whole kick starter mechanism out of the cover to solve the problem. Maybe that will work for you.

Thanks - it is a longshot but will give it a try - never use the kickstart anyway! I'll keep all updated.

I had a bad noise after changing the belt on my LX150. It ran but didn't sound right.

I caution you to stop riding until you are certain you reassembled everything correctly. I didn't and destroyed the spines on the crank and the variator. That was the end of that scooter lest I rebuild the engine. It was a sad day.

Here's a post with more details: https://scooterinthesticks.com/2007/01/non-riding-adventure/

And here's a picture of the variator after about 50 miles if I remember correctly.

Are there metal shavings in the bell housing splines or is that just grease? Hard to tell in the photo.

I wasn't there when the technician took it apart so I'm not sure what he saw. What I do remember was the sinking feeling I felt when he told me over the phone what had happened.

On the plus side, it gave me the opportunity to buy a GTS 250. My wife knew how stricken I was with the loss, and how much I loved that scooter. Bless her heart, she just said, "Buy another one."

And I did.

As much as she is uncomfortable with me riding, she still surprises me with her support. Like a couple of years ago she bought me a BMW K75 for my birthday.

I'm wondering now when she's going to surprise me with a Harley Davidson 883 Iron. I'm getting old fast and my potential Harley days are numbered!

That belt looks far out on the clutch pullies to me. Are you sure you tightened the outer variator plate onto the boss, and not the belt?

For me belt looks sitting good.

Are all hoses connected? Air filter box is being moved when removing variator cover, so check if engine head vent and carburetor intake hoses are in palce.

This is a good suggestion. Make sure the belt is seated deep in the clutch (you have to expand it by hand when installing it) before tightening down the variator. This gives it sufficient slack to clear the variator pulley when torquing the nut.

Sticky starter Bendix?

^^^

Bingo!

This is heartbreaking! Yes, I have not driven it at all. As a matter of fact, we've started it for all of 30 secs. each time just to see if the noise is still there. It is such an offensive sound, am sure it is not good so no riding! Hope you get that Harley Davidson 883 Iron soon!

Thanks - photo was taken after it was run to see if sound was still there (so, as I understand it, the belt works it's way towards where you see it). Yes, sure that the plate has been tightened onto the boss and not the belt. I was sure that was the case the first go around and was disappointed after redoing it (multiple times) only to hear that same damn sound!

Good suggestion - can't imagine that would make a screech like that but adding this to things to check! Thank you.

We thought it might be a starter noise but seems to be working well. Took it out, cleaned it up and reinstalled just to be sure. It is back once opened up so not sure how else we could check? Thanks - will perhaps give it another look!

That is just grease. We did find some metal shavings where the variator sits but not sure how long they had been there. Has not been ridden or even run for any length of time since this belt change fiasco.

So I was finally able to find a place to upload the sound! Mind you - it is much lounder and obnoxious than it sounds here.
https://freesound.org/people/taralynnc/sounds/586845/

Closing the loop on this one....

After all was said and done, the variator was rubbing on the case/kickstart - must have bent thin metal plate inside ever so slightly when removing it. We had looked but did not see rub marks initially, pretty sure it was because I was shutting it off quickly after hearing noise - was afraid I was grinding something down (which I was).

Last night we let it run for a good minute, even though it hurt to do it - sure enough we could see where it was hitting. Thin metal plate on inside of cover must have gotten bent while fighting with the cover to come off. Bent it back, easy fix.

I will look on the bright side and know that my clutch, case and associated parts have never been cleaner. Now if I could just get that new locking nut from ScooterWest, I will be back on the road.

Thank you all - you are all rockstars!

What a horrible sound! I'm glad you fixed it!

Thanks for posting back the solution. Do you happen to have a photo of the rubbing?

I'm just not clear where the variator would rub, as I seem to recall a fair amount of clearance away from the crankshaft. But yours could not have been very bent, or you would have noticed it right away.

Did you recently replace anything on the variator or outer plate? Does the variator say RMS on it?

Photos attached - hard to see the rub on the variator cover but it was there.

Well, I guess I was not too far off. The whole kick start assembly is a damnable nuisance. Like I mentioned before, I gutted mine and never looked back.

Glad you figured it out. Congrats!