Can't fix the flat spots issue on rollers - SOLVED!

kenjidnb · Post by **kenjidnb** » Fri Aug 15, 2014 6:35 am

My vespa lx150 has only 5K miles on it and I've already changed the rollers 4 times.
I will notice the rattling due to flat spots on the rollers soon after replacing them, as early as 100 miles riding with them. I have tried rollers from different make and weight, piaggio stocks, malossi and dr pulley. I did upgraded the vario with a Malossi kit but this did not help. I also tried to put a dab of lithium grease and dry lubricant in the vario. Even though the dr pulley rollers were suppose to slide, they also ended up with major flat spots...
I also went as far as changing my riding style, accelerating much more progressively.
At this point I am out of options, I still have no clue what could be causing this...

scootERIK · Post by **scootERIK** » Fri Aug 15, 2014 3:01 pm

Have you thought about trying sliders?

kenjidnb · Post by **kenjidnb** » Fri Aug 15, 2014 6:02 pm

Such as the DR. pulley? I have tried this and this was the worst, the round part of the slider went flat in less than a week...

KrispyKreme · Post by **KrispyKreme** » Fri Aug 15, 2014 6:36 pm

Changed them 4 times? There will be "rattle" at times. It's normal.

Edit-Something isn't right.

Post by **ericalm** » Fri Aug 15, 2014 8:15 pm

What do the rollers look like after 100 miles?

Wearing actual, physical flat spots on the rollers in 100 miles is pretty unlikely no matter what else could be going on in there. Are you 100% sure that the rattling is the rollers?

I would try two things: weighing them and measuring them with calipers.

Are you properly torquing the variator nut every time you out it on? And have you replaced the nut?

100 miles worth of friction shouldn't wear them down much unless something is literally shearing off chunks of roller. There would be a lot more noise than a rattle and evidence of issues elsewhere: marks on the variator ramps and back plate, lots of dust and debris from rollers.

I once had a roller/transmission rattle issue that I tried to chase down for a year before discovering it wasn't a transmission sound. It was a loose valve. I discovered this when it dropped and destroyed my top end.

kenjidnb · Post by **kenjidnb** » Fri Aug 15, 2014 9:27 pm

Rattling stops for a little while after I replace the rollers. There are well defined flat spots on the rollers, will attach pics of them soon.
New nut and proper torque at each replacement, yes.

The rattle is clearly coming from the transmission box, I feel it the most when accelerating from zero to 10 mph, scoot struggle to engage while it heavily vibrates (this is what I actually called rattle). I also thought that it could come from the clutch itself but I couldn't find anything abnormal after inspecting it.

charlie55 · Post by **charlie55** » Fri Aug 15, 2014 10:26 pm

Please don't take this as an insult to your intelligence, but here's a few ideas for stuff that can be ruled out or in:

- When re-assembling the variator, did you make sure that the three guide bushings (those U-shaped plastic parts) were in place on the ramp plate? Could you possible have neglected to re-install them?

- Are you sure that the rollers you've been using are not only the correct weight, but also have the correct dimensions?

- Doe the inner plate slide freely over the collar bushing?

I've been looking at pages ENG-14 and -15 in the service manual:

http://www.wotmeworry.org.uk/manuals/Vespa/LX150/

and that's about all I can think of in terms of stuff going wrong.

KrispyKreme · Post by **KrispyKreme** » Fri Aug 15, 2014 11:55 pm

kenjidnb · Post by **kenjidnb** » Sat Aug 16, 2014 12:45 am

Charlie, absolutely no offense taken at all. I really appreciate the help that you are providing.

I made sure that the guide bushings were properly in place (duh

).
Aside from using the dr pulley once (which I'm not sure are exactly rated for my malossi vario), every rollers I used were the proper size and weight (19x17 and about 10ish grams)
When I assembled the vario on the collar bushing, it felt like it was sliding in and out very well and without any wiggle room.

One thing I noticed though is that the ramp plate doesn't feel snug on the axle. It seems to wiggle a bit around the splines when I slide it in. Although, I think this shouldn't matter since the guide + variator nut should hold it in place.

charlie55 · Post by **charlie55** » Sat Aug 16, 2014 12:51 pm

Well, I'm stumped.

Are you using a stock belt with OEM dimensions, or an aftermarket one?

I guess the only remaining thing I'd do at this point is disassemble it and check for casting flaws/roughness in each of the roller channels, and also the surfaces of the ramp plate that contact the rollers. Maybe even get in there with a Dremel and some polishing rouge.

az_slynch · Post by **az_slynch** » Sat Aug 16, 2014 8:54 pm

kenjidnb wrote:The rattle is clearly coming from the transmission box, I feel it the most when accelerating from zero to 10 mph, scoot struggle to engage while it heavily vibrates (this is what I actually called rattle). I also thought that it could come from the clutch itself but I couldn't find anything abnormal after inspecting it.

Have you tried scuffing up the clutch shoes with some medium-grit sandpaper? Might also try scuffing the contact surface of the clutch bell. The engagement issue makes me wonder if these surfaces have become glazed and are struggling to hook up.

Does the scooter "rattle" from the transmission on deceleration? I've come across a few scooters where the lubricants had dried up or gunked up enough that the secondary sheave was sticking on deceleration and letting the belt run loose and dropping tension on the variator, which would allow it to clatter and get out of whack. You mention having 5K on the bike, which seems low for driven clutch issues, but it might be worth a look anyway.

lovemysan · Post by **lovemysan** » Sat Aug 16, 2014 9:03 pm

0-10 mph sounds like clutch to me. Sand the clutch pads. Sand the clutch bell. See if it improves. Could possibly be the clutch bell warped. Or oil contamination of the clutch pads.

kenjidnb · Post by **kenjidnb** » Sat Aug 16, 2014 11:03 pm

I opened the transmission this morning and took a few pics:

The Vario is dirty mostly because I used grease this time

This roller have been used for less than 200m, you can already see a few flat spots.

This one is a previous roller that worn out over 600 miles. The flat spot is very distinct here.

kenjidnb · Post by **kenjidnb** » Sat Aug 16, 2014 11:18 pm

I replaced the oem transmission belt last month with a non-oem belt but this issue was already happening before.

The clutch pad and the bell are cleaned/sanded every time I open the transmission cover, when I inspected it this morning it all looked good.
The scoot doesn't rattle on deceleration, it's really only when I accelerate from a stop that I feel it.

I also noticed that the vario doesn't slide very well in and out from the ramp plate. The 3 guide bushings get kinda stuck in the vario, especially in low gear position. Because of that, I replaced the malossi vario with the stock vario this morning. The stock vario seem to slide much better than my malossi.

If that's still not helping, my next move will be to replace the entire clutch assembly.

charlie55 · Post by **charlie55** » Sun Aug 17, 2014 12:09 am

The circled area is one of the three guides against which guide bushings slide. It's hard to tell from the photo if that dark streak along its side is just a surface smear of grease, or if it's grease that's been caught on a roughened surface. If it's that latter, then that could be the cause of the ramp plate hanging up on you. In that case, a buffing with some 2000 grit wet/dry sand paper could set things right. You could also look at the part of the bushings that bear against the guide "posts" to see if they've developed any scratch lines from rubbing against rough edges.

Since the ramp plate is actually held stationary by the collar bushing, the "stickiness" would affect the ability of the drive face to move inwards to force the belt outward as you accelerate. Likewise, when you decelerate, the belt would have a harder time moving inwards and forcing the drive face outwards.

Now for a final "Hail Mary".....

Going back to your observation that the ramp plate has a bit of "wiggle room" vis-a-vis the axle/crankshaft, I'm now starting to wonder if that may be allowing it to be a bit off-center in relation to the drive face. Sort of like this extremely exaggerated illustration:

|
| \
| :
| /

In other words, the hole in the center of the ramp plate is large enough to prevent it from being perfectly centered with the drive face.

Here again, I'm just guessing based upon what I can see. As always, it'd be a whole lot easier if we could get a "hands-on".

kenjidnb · Post by **kenjidnb** » Tue Oct 14, 2014 12:59 am

I followed the advices received on this thread and I believe that my flat rollers issue is now resolved!
Apparently my clutch pads and bell were pretty glazed, so I sanded the heck out of them.
3 months and a 2K miles later, still no symptoms of flat rollers. Funny the glazed clutch caused my rollers to go flat but I'm just happy I don't have this problem anymore.
Thank you all for helping me figuring this out!

jrsjr · Post by **jrsjr** » Tue Oct 14, 2014 10:45 pm

Thanks for the excellent write-up (with photos) and the follow-up. I put a link to this thread in the General Maintenance Forum.