CVT operating temperature

[frankenscoot]

Has anyone measured the temperature at the cvt?

One manual says the grease at the clutch should be able to withstand 240C i belive i have read, and in another 240F?

Neverthless kymco says it goes over 100C / 212F and a study paper about cvt says 150C / 302F and above.

[aeroxbud]

It will vary as some CVT designs like the Piaggio are vented and have air passing through. Others dont.
It's hot though. When I was changing multiple rollers for comparison on the Aerox. I used to wear gloves as the variator was so hot after many launches.

[Zino]

I only used a temp gauge to measure temps of case .
Before and After I drilled holes in it
it would get in the low 100's no where near boiling water tempature .

[frankenscoot]

Thank you.

It would vary yes, but in the design they have a expected working temperature..

I belive the needle bearing in my qmb is rated to work between 80C / 176F and 110C / 230F..

230F sound closer to the figure in the manual.

Some say use nlg2 grease, but that doesnt say much.

[frankenscoot]

May 8, 2023 7:02:11 GMT -5 Zino said:

I only used a temp gauge to measure temps of case .
Before and After I drilled holes in it
it would get in the low 100's no where near boiling water tempature .

That is also helpful, thank you.

Do you mean 100F after drilling?

I think the bearing would be 20C / 68F hotter than the driving face.

[snaker]

There are a lot of design differences in small engine rubber belt CVT's.
These things run way hotter than simple v-belt pulley systems, for two reasons.
1. The sheaves open and close, forcing the belt to upshift and downshift.
That's done by squeezing the sides of the belt to force the belt up in one pulley, which causes the belt to force itself down into the other pulley.
The stronger the fly weights and the contra spring, the stronger the forces
2. The Torque Sensing
TS is all about the angle, which causes the driven pulley sheaves to rotate against each other and rub against the belt sides.
Essentially, the belt goes with one of the sheaves and slips against the other, not a lot, but still it adds up.

The amount of upshifting and down shifting have an affect as well as the amount of hp applied.

There seems to be differences in GY6 CVT and CVT case design.
Different shape fan blades.
At least some of the case covers have a filter at the inlet that a lot of folks don't know about.
That needs to be maintained as well.

[Zino]

The outside cvt cas is what I aimed the thermometer at

Closer to 100 degrees farenheight not celsius warm to the touch

The interior cvt parts I have hot swapped they are hot to the touch .
I do have to use gloves .

So i agree the interior parts are probably 40-60 degrees Higher temps

[frankenscootdk]

Thank you guys. Will try to estimate from your experience and the bearings rated max temp, until i can measure somehow.

[FrankenMech]

The temperature at the point of heat generation will be much higher than the case. The temperature the grease must withstand is even higher because it is an instantaneous temperature exposure. Most of the manuals were written using metric measures and very poorly translated. Use °C measurements and specifications.