Author Topic: Drive belt and variator roller advice  (Read 1131 times)

eamartin

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Drive belt and variator roller advice
« on: April 19, 2020, 05:59:08 PM »
I have a junker Agility 50 4T which now runs.  I've removed the drive system case to inspect the components (which I've never done before) and some things don't look as bad as I expected.  Each of the 8.5 gr rollers have a few flat spots on them and the O.D.'s are near or below the service limit minimum.
The drive belt looks good as far as I can tell.  The belt starts life new at 17.5mm width.  Service limit minimum is 16.5 mm.  This belt measures 16mm.  Can I expect any noticeable improvements if I replace either the rollers or the belt?

OaklyJava

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Re: Drive belt and variator roller advice
« Reply #1 on: April 19, 2020, 06:09:17 PM »
Yes you should install new rollers I don't know how much of a difference you'll see. I don't know about the belt haven't had to deal with that on my agility.

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TBR125

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Re: Drive belt and variator roller advice
« Reply #2 on: April 19, 2020, 06:52:58 PM »
As Stig said definitely replace the rollers. Your power band will noticeably smooth out especially if they have worn to the slider stage. Regarding your scooters belt, the difference of belt wear is minimal compared to the rollers. Unless, it has worn so narrow it won"t reach the full diameter of the variator, or it breaks. I have the Agility 125 with the new belt at 20mm with a minimum wear width of 16mm. Should I be concerned that my manual has a misprint? Obviously the 125 should need a stronger belt for the added power and torque.
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eamartin

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Re: Drive belt and variator roller advice
« Reply #3 on: April 19, 2020, 07:39:47 PM »
Are there any rollers I should avoid?

TBR125

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Re: Drive belt and variator roller advice
« Reply #4 on: April 19, 2020, 08:26:44 PM »
For the ultimate shifting experience I have stuck with Dr. Pulley Slider weights. To avoid, I think all of the 5 dollar "performance" weights. Especially those advertised to increase engine power:)

Note on Dr. Pulley Sliders: They may not act like the equivalent roller weight. As in a 14g for the my agility acts like a 15g roller (Your experience may vary)
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eamartin

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Re: Drive belt and variator roller advice
« Reply #5 on: April 20, 2020, 12:08:10 PM »
I'm getting conflicting information about the weight of the stock roller weights.  Mine weigh 8.5 grams each.  Some have said they come stock at 5.5, 8.0, etc.
Anyone know the stock weight?

TBR125

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Re: Drive belt and variator roller advice
« Reply #6 on: April 20, 2020, 02:25:34 PM »
8.5 sounds correct. If you post a picture I think I can tell you if they are stock.
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eamartin

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Re: Drive belt and variator roller advice
« Reply #7 on: April 20, 2020, 09:05:56 PM »
Thanks for the offer.  Since I know the weight of the rollers now on the scooter as 8.5 grams, I just ordered some 7.5 gr weights.  They'll be new and round. Plus, I'll get to see what kind of difference a lighter roller makes.  Thanks again.   

TBR125

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Re: Drive belt and variator roller advice
« Reply #8 on: April 21, 2020, 03:50:55 PM »
Dr Pulleys aren't cheap so I would only use them once you are set on a weight. For trying different ranges a cheap variety weight set is fine. They just wear a little faster.
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eamartin

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Re: Drive belt and variator roller advice
« Reply #9 on: April 21, 2020, 04:42:04 PM »
Dr Pulleys aren't cheap so I would only use them once you are set on a weight. For trying different ranges a cheap variety weight set is fine. They just wear a little faster.
That's what I thought.  This will be interesting.

eamartin

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Re: Drive belt and variator roller advice
« Reply #10 on: April 26, 2020, 03:21:29 PM »
I ordered and received 7.5 gr weights.  I re-weighed the old weights in ounces on my little postal scale and apparently made some mistakes in my original ounce to gram conversion.  Turns out my old weights are between 6.6 gr and 7.0 gr.  With the new weights things seem a bit smoother and my top speed increased on level ground and down hill by 1-2 mph.  From here to the stop sign (1/2 block slightly uphill) I top out about 1 mph faster.  Only issue is a slight hesitation at take-off.  Will heavier rollers cause this?  Or might I have a carb issue I did not notice before?

TBR125

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Re: Drive belt and variator roller advice
« Reply #11 on: April 26, 2020, 09:46:45 PM »
Heavier rollers will cause the belt to "Shift" at lower rpm=lower torque+power. Less power on start-off but economical fuel usage (if you don't peg it) and lower rpm at top speed means your revs wont be the limit. My downhilling was limited by the engine floating valves at 11000 rpm.
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