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Yamaha Beluga CV80 Variator Belt and Roller Weights

TL;DR: use a BX32 belt and 6.0g weights

Side View of a Yamaha CV80 Beluga, 1982 Model

Finding a Replacement for The Discontinued CV80 Drive Belt

I have a Yamaha CV80 Beluga, 1982 U.K supplied model. These were made from 1981 until about 1987 I believe. I've recently been recommissioning my one, and as part of that I needed a new drive belt.

The original CVT drive belt was Yamaha part number 17M1764110. Unfortunately, these are no longer available. The previous owner had installed a fan belt from some sort of Toyota 4x4, but it was way too small and the teeth had been eaten off by secondary sheave.

Looking at the manual, I had a picture of how the belt should sit, so after a bit of testing, I found a belt that fitted just like the original and was the correct width (17mm). The belt I used was a BX32, and that's the one I'd recommend if you need a replacement for your own Beluga 1981-87.

BX32 Belt on a CV80 Beluga Drivetrain

The BX32 is widely available in the UK, Europe and North America, and very cheap. The "32" is the size in inches internally. I did try and find an equivalent metric belt, but couldn't find one that exactly matched the width, diameter and tooth pattern.

The belts are available in half inch increments. I tested a BX31.5 which was somewhat too tight, limiting top speed. I also tested a BX33 but it was too large and hit the casing. Possibly a BX32.5 would be optimum, I need to source one to test further.

Note that if you're changing a belt on a Beluga, you will need to drain the oil from the rear of the housing first. The drive belt cover has a seal inside that holds the oil in, so you'll make a big mess and get oil all over your belt and variators if you don't drain it. This could cause a slipping transmission if you don't keep those parts clean and oil free.

Bonus: Improving Acceleration and Hill Start Performance

While I had the belt cover off, it was a good time to see if I could replace the clutch rollers. The stock roller weights would have been about 10 to 11g when new, which makes the bike very sluggish on initial take-off. I replaced mine with 6.0g rollers. The dimensions of the rollers are 15x12mm, which is the same size used on the Yamaha Aerox and related scooters. Again, these were very cheap and easy to find on eBay.

My old rollers were quite worn, so it was good to replace them anyway. I gained a significant improvement in acceleration from 0-20mph (0-30km/h), and also improvements in steep hill climbing.

A lot of the credit on the idea to change to these weights comes from this old forum post from the long shut down CV80 Riders Forum.

Replacing the rollers is much like any other scooter. Firstly, remove the nut holding in the front variator - if you don't have an impact gun you will need to hold the crank from turning. This can be done using the fan bolt holes on the flywheel assembly on the other side of the engine, once the plastic fan shroud and fan is removed. Once the nut is off, carefully pull off all the parts of the primary sheave, and very gently pry apart the primary sheave assembly to reveal the rollers.