shredded drive belt By nerdtastic (Read 1,641 times)

[nerdtastic]

OK so I was headed up to the mountains with my daughter for a relaxing time and to escape the heat of the valley. It is a gorgeous twisty mountain road and we are having a great time until... snap! RPMs spike up and no power to the rear wheel. I coasted to a stop put it on the center stand and called for help. We made it home safely (we were meeting friends and they had a trailer). When I got the cover off, yep you guessed it, little pieces of drive belt everywhere. So now I have a broken scoot and I am back to the bus to get to work .

A few questions for those who have done this more than I have,

1. is there really a difference between the types of belts i.e gates, or no name generic (a local shop has a generic and I am trying to decide if it's worth waiting for a Gates from scooterbelts.com)?

2. I have seen Kevlar belts advertised are they really worth it for a daily driver?

3. I know I need to pull the variator and and the pulley off and inspect for damage and clean any bits of belt out is there anything else specific I should be looking for?

4. the most important how do I keep from getting stranded again, how often should I be inspecting the belt and what should I be looking for?

5. Sense I am going to have to pull everything off I am thinking that I might go to sliders to get a little more bottom end any suggestions of weights?

any other thoughts or ideas would be appreciated

[Bashan]

Wow, what a bummer on your outing! Well, at least you had a bud that could pick you up. I can give you my opinion on a few of your questions, I'm sure others will chime in too.

• Gates belts are definately superior, they're all I use anymore. I've never used a kevlar since the gates work so well.
  
• When you pull your variator look for flat spots on the ramps and make sure the boss isn't sloppy, everything wears out eventually. Make sure the little guide clips aren't getting worn, if one breaks in half your variator is toast.
  
• I check my belts every 500 miles, look for fibers starting to come off of the side. Measure the width of the belt, the second number on the belt is the width in mm, a couple mm wear is quite a bit.
  
• I've never dealt with sliders, I just like rollers, call me old fashion.

Rich

[sprocket]

Kevlar belts are too stiff and when the break they explode into millions of tiny hairs about 1/2" long...

Bando also make good belts...I think Gates owns them now...

I change my belt every spring.. and carry the old one with me...after two years the belts are dry and no longer any good...

Sliders are smaller steps (less effect) than rollers... they are good for fine tuning the variator.. but
often are not needed in a daily driver...

[nerdtastic]

Well I have more info I broke out the impact wrench and pulled off the variator and the clutch. The good news is nothing appears to have broken and there wasn't any belt debris, that is the good news. The bad news is the roller weights do appear to have a lot of wear they are worn flat in several spots so those are going to need to be replaced. I also found this:



as you can see the belt is not getting all the way to the top of ether the variator or the fan and there is a big difference between the two as you can see below:



that is the variator about 5mm from the top

and the fan



as you can see is about 10mm from the top

I think I might have found the cause of the lack of travel though
this is a shot of the pins on back of the variator that hold the plate in place.



as you can see they are badly worn to the point that the plate is catching and can't travel any further. I think i am going to be getting a new variator in addition to the belt.

The the variator is about 10mm smaller that the fan and from other posts it sounds like that will rob me of top end, am I reading that right?

I also checked the roller weights all exactly 13 grams.

So here is what I think I need to do. I need to replace the variator for sure and I think I want to go with a "performance variator" that is the same diameter as the fan. With it get 3 sets of weights in 12, 13, 14. The idea being 13 might be the right size but the travel is being restricted by both the size mismatch and the rather nasty wear on the pins. I don't want to go a lot heavier as I am pretty happy with the acceleration right now but if I could get about another 4-5 MPH on the top it would be great.

Does that sound about right or has the brake cleaner gone to my head and I am missing something important...



an thoughts or ideas would be helpful.

[ce]

Looks like they left out the slide guides on those pins, that's why they're worn away.

Good plan on the variator with the new roller combo, sounds like the 13 grams were holding back a little, try 3 12s and 3 13s which is 75, to lower your total roller weight by 3 grams.

It'll be a litle peppier, and as long as the RPMs don't go too high, you might get a little more top end.

If that don't work, try 3 14s and 3 12s, which is 78, same as 6 13s

If that don't work try 3 13s and 3 14s, which is 81

And, of course, you can always go 6 12s, which would be 72, and that may be your lucky number.

[sprocket]

I would just replace the whole variator with a Prodigy, NCY, Dr. Pulley etc.. etc...

[nerdtastic]

Yep Sprocket that is exactly what I am doing, I just ordered a NCY variator from a local shop it's coming from back east though so I am still grounded until next week.

thanks for the ideas on tuning the roller weights ce that is what I was looking for a concrete set of steps to walk through to try and get the best balance. Sadly between budget and time constraints performance is going to have to take a back seat to just getting back up and running.