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Post by torinoman on Nov 4, 2023 16:09:17 GMT -5
Greetings group! I'm in dire need of your expertise! I have a 2001 Yamaha Zuma that has approximately 4 mm of unused variator and clutch. I'm trying to source a longer belt to get my full travel. So far I've tried a Gates pl-20302, a Malossi 6118140, and the stock Yamaha belt. The gates and malaossi were supposed to be longer, but fit the same and measure out very close.
Stock belt size is 738x16.5x28.
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Post by geoffh on Nov 6, 2023 16:17:07 GMT -5
Sorry for the late reply,but stick with the OE belt there isn,t a better belt for a stock set up,you could try shimming the variator boss to gain a tad of top end but you will lose low end,those Yamaha design guys know their stuff.
Geoff
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Post by Lucass2T on Nov 7, 2023 8:24:59 GMT -5
Greetings group! I'm in dire need of your expertise! I have a 2001 Yamaha Zuma that has approximately 4 mm of unused variator and clutch. I'm trying to source a longer belt to get my full travel. So far I've tried a Gates pl-20302, a Malossi 6118140, and the stock Yamaha belt. The gates and malaossi were supposed to be longer, but fit the same and measure out very close. Stock belt size is 738x16.5x28. You could look at the belt lenght of a Yamaha Axis, Malaguti F10 or Aprilia Sonic. They have a longer belt than the Zuma. Top Performances carry an semi-overrange rear pulley which takes longer belts. Maybe look at one of those semi-overrange belts. They may be exactly what you need. |
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Post by FrankenMech on Nov 7, 2023 11:00:47 GMT -5
To even get close while experimenting with belt lengths stick with one particular brand. Even then with variations between manufacturing facilities sizes may vary. You are only looking at a belt 6mm longer than the ones you are using now and your OEM belt may be worn. Belt width makes a large difference in ratios. A new belt of the OEM type you are using may help gain back that 4mm of pulley use.
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Post by torinoman on Nov 15, 2023 10:32:47 GMT -5
Great ideas all! Thanks a bunch for the help and advice. Not quite ready to pull the trigger on an over range set up yet. I know that would probably be the best thing, but unfortunately, money is a concern. Since my original post I have also tried a Bando 757x17.3x28. It was just too big everywhere. Too wide and long. I will say that Bando is the first manufacturer that I've come across that has accurate dimensions. Bando also offers a 749.5-16.5-28. If the measurements are accurate, that might be the ticket. Any one use that belt? As mentioned, I haven't found anything better than the stock Yamaha belt so far. Also, I am currently not running any shims. If I put any washers in at all, even a half mm, my top speed drops off at least 5 mph and RPM's shoot up to mid 9000's from mid 8000's. It just kills me to have that much unused pulley. I'm attaching some pics for reference. This is where the belt rides with the stock belt and no shims. Yields about 43 mph on flat land at 8500-8800 rpm.   |
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Post by torinoman on Nov 15, 2023 16:33:26 GMT -5
My apologies about my delayed reply to the folks that commented. I Didn't see any notifications about activity on the post. I'm signed up for email alerts now!
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Post by Zino on Nov 15, 2023 19:08:57 GMT -5
The stock variator is a poor design
Most stock variators are they are a easy way to cap top speed to comply with scooter laws
A malossi or polini variator gets better travel with the yamaha stock belt and shift much better .
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Post by torinoman on Nov 15, 2023 20:20:32 GMT -5
I'm actually messing with it right now off the bike. Regardless of belt length, It would appear that a belt thin enough to drop all the way down in the clutch is way to thin to climb the variator. Likewise a belt thick enough to climb the variator when it's closed doesn't drop all the way down in the clutch. So what's the lesser of 2 evils? I have aftermarket 1000rpm clutch springs and contra. 4.6 gram rollers. I'm going to put the stock contra back in to make sure the new spring isn't limiting my travel for some reason.
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Post by torinoman on Nov 15, 2023 20:21:49 GMT -5
The stock variator is a poor design Most stock variators are they are a easy way to cap top speed to comply with scooter laws A malossi or polini variator gets better travel with the yamaha stock belt and shift much better . |
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Post by torinoman on Nov 20, 2023 15:12:11 GMT -5
Going back to the stock contra spring was a no go. She dropped out of the power band on hill climbs and fell on its face.
Taking Zino's advice and going to try a variator. bought a top performances variator kit from bigmatthew86, so hopefully this will give some improvement! Anybody install one of those kits? Any special shimming?
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Post by Zino on Nov 20, 2023 17:52:39 GMT -5
Try it without shims it is probably 95% right out of the box .
Do the sharpie test and see how close it gets to rock bottom on inner edge of variation for best take off .
And how much is left on the outer edge for top gear .
I shim basically every cvt,
I rebuild with aftermarket parts to get the max on inner and outer edge of variator .
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Post by torinoman on Nov 20, 2023 18:02:56 GMT -5
Try it without shims it is probably 95% right out of the box . Do the sharpie test and see how close it gets to rock bottom on inner edge of variation for best take off . And how much is left on the outer edge for top gear . I shim basically every cvt, I rebuild with aftermarket parts to get the max on inner and outer edge of variator . |
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Post by torinoman on Nov 20, 2023 18:07:21 GMT -5
Thanks Zino. That's exactly my plans. I have a 750mm belt coming too in case the belt in the kit doesn't sit right. Have you ever messed with this particular kit? I've heard some aftermarket variators needs shimmed BEHIND the boss... I've never done that. I assume that's for proper belt alignment?
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Post by Zino on Nov 20, 2023 19:44:48 GMT -5
Never used that variator
The Top performance stuff was designed to work well with yamaha products.
One of the guys from Europe may be able to verify thatthey were a high performance division of Yamaha/MBK
Follow the kit instructions if it says shim behind the variator try it
I have shimmed behind variator before.
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Post by torinoman on Nov 20, 2023 20:25:12 GMT -5
Never used that variator The Top performance stuff was designed to work well with yamaha products. One of the guys from Europe may be able to verify thatthey were a high performance division of Yamaha/MBK Follow the kit instructions if it says shim behind the variator try it I have shimmed behind variator before. Hopefully it has some instructions with it! Shouldn't be too hard to figure out anyway |
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