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General => Technical | How To => Topic started by: Chris0381 on July 12, 2020, 04:27:10 PM

Title: Using a 1mm longer belt
Post by: Chris0381 on July 12, 2020, 04:27:10 PM
Just browsing for a new belt. The S8 uses a 728 mm stock belt and this website has no 728's but have plenty of 738's. Would using a 1mm longer belt make a diff. providing the width is still 18 mm and V-angle 30 ?

Also, if I go to racing planet and run my model of scooter, some of the belts that come up are in the range from 737 to 748 mm with slightly diff. V-angles. So I have to assume 1mm will be no real diff and should grab this one along with new clutch pads.

https://www.partsforscooters.com/106-120-Bando-738-18-30-CVT-Belt (https://www.partsforscooters.com/106-120-Bando-738-18-30-CVT-Belt)

My goto Scubatunning.ca doesnt have those parts listed unfortunately.
Title: Re: Using a 1mm longer belt
Post by: TBR125 on July 12, 2020, 05:44:26 PM
Your top end ratio will suffer a minuscule amount(about the same as roller wear). Also the start off will be at a slightly higher ratio although 1mm difference is marginal.
Title: Re: Using a 1mm longer belt
Post by: Chris0381 on July 12, 2020, 05:56:19 PM
Actually, I just took off my cover and the stock belt is 728 mm not 737. So now a 10mm diff just under a half inch may be a bit more dramatic. I'll edit the original post.
Title: Re: Using a 1mm longer belt
Post by: TBR125 on July 12, 2020, 06:22:36 PM
10mm will have a 10 times less marginal effect than 1mm(if my math is right). Over the radius of the clutch and variator 1cm will not reach or pass the edge of either face which eliminates the de-rail worry. I think it would work although the drive boss might need to be shortened to take up the extra slack to keep the weights from being loose before accelerating.
Title: Re: Using a 1mm longer belt
Post by: Chris0381 on July 12, 2020, 10:09:42 PM
I've located a 728 x 18 x 30 belt and will get it tomorrow.  1mm diff shouldn't be too bad. Actually the stock belt only has a P/N but my belt that on there now is a 728 x 18 x 30 Bando.
Title: Re: Using a 1mm longer belt
Post by: de dee on July 13, 2020, 02:47:12 AM
my new downtown 300i came with a belt 6 MM . longer than stock, top problem was high RPM. at speed,.  but it lasted for a long time  a few years later when I changed belts I found it was the problem   then I got into dr. pulley sliders and grinding new paths in the variator, matching malossi design,. of today,.  to bad I have not got the money to rebuild my downtown I was dreaming to rebuild to a 350 if the 350 would fit the motor of the 300, the cylander and piston if available,.  then I think Im 87 years old with a farily new Piaggio 350 only 35,000 Km.s on it, I just installed a malossi belt with the variator with new Wt.s  and I changed the wiring from the turn  USA lights to the LED euro lights and I like this scooter a lot.and I dream of riding to the west coast a 10,000 Km., ride,.  but thous Dr.s  keeping me healthy make to many appointments,.  minor things like cancer,.  blood suger level Etc. Etc.  and I have to keep up to my step Mom who is over 100
Title: Re: Using a 1mm longer belt
Post by: john grinsel on July 13, 2020, 11:38:44 AM
I probably have as many miles on rubber band drive scooters as anybody.....over 400,000 miles since 1990,and hate walking-----use OEM belts from your dealer and you probably will not have trouble or problems.  Not happy with your scooter's performance, get some thing else, cheaper in the long run.
Title: Re: Using a 1mm longer belt
Post by: Chris0381 on July 13, 2020, 01:30:03 PM
I probably have as many miles on rubber band drive scooters as anybody.....over 400,000 miles since 1990,and hate walking-----use OEM belts from your dealer and you probably will not have trouble or problems.  Not happy with your scooter's performance, get some thing else, cheaper in the long run.

I am happy with my performance, I would like to change the belt as its approaching the service limit thanks. BANDO belts are as good as stock and maybe even who produces Kymco belts.