Drive Belt Inspection

[Snorvey]

Havign finally got the cover of with the help of a very large rubber persuader, i got a look at the drive belt today. I was worried that it might be on the way out as there was a screeching noise coming from that area after quite a number of miles. It hasn't repeated itself since then, but most of my journeys have been relatively short (less than 20 miles).

I don't know much about drive belts, so I look a few pics and a few measurements while I was it at. Any thoughts would be most welcome.

The belt itself would appear to be as new. There are no cracks or missing teeth. The maximum deflection when pushed is about half an inch (should have measured this more accurately, I know). Measured over several different points, the belt is 22 mm wide and at it's narrowest (at the tip of the teeth, its 16mm). The cogs etc all seem to be in good condition.

As I said, any thoughts (particularly in relation of the screeching when warm) would be appreciated.

[Stig / Major Tom]

How many miles on the belt?
What are specs for new belt per your manual, and limit of wear?
Will you be cleaning pulley surfaces?
Stig

[de dee]

 mitsuboshi spec sheet 2011  length 1004 mm.  width 25.5 angle 30  degree  2011 downtown to now,.  did not see what the minimum width is, I think it is 23 mm.   , all belts I have bought are 24.3 wide ,.  the way to check belt is to take it off, and flex the belt to see if there are cracks showing in between the cogs inside and outside ,.  you can use the boss to bend the belt too check for cracks, so you don't over bend it,. 

[ole two wheels]

Snorvey, The screeching sound is the same sound that tires make on pavement when you use too much power and the rubber breaks loose and spins the tire. (lost grip) As Stig some rightly mentioned, cleaning the face plates will help. Belts do stretch and you need to know the defection limit. The only part of the belts thats contacting the face plates  are the edges. As the belt wears it becomes more narrow and there fore increasing the deflection. The teeth do not contact anything and are only there to aid in cooling the belt. A cvt generates a lot of heat and the ventilation inside the belt housing must be un-obstructed. In the pictures, the belt looked good, but could be worn enough to make it slip. Don't know if any of the helps, but that's the low down on all CTV drive belts.
cheers


Mac

[Snorvey]

Thanks lads. You know what, i think I'm going to order myself a new belt. I'm quite happy to fit it myself, but i recall you need a special pulley holding tool make things a bit easier?

Also, cleaning the pulley surfaces.... With what? Degreaser? Or just a soft cloth?

Thanks again.

Ps the service manual  says the belt was changed (or inspected - the book just had a tick next to 'inspect/replace belt') 4500 miles ago - before i bought it. I think for peace of mind,  I'll change it.

[de dee]

when you get new belt measure it with tailors tape should be about 1004 MM.  width 24.5 MM. or more, 

[ole two wheels]

As far as what to clean the two sides of each pulley with. I'd use 70% rubbing alcohol. It dries completely and leaves no residue and will remove any oil. Do that while the old belt is off.


Mac

[Snorvey]

I've seen a telly program on the Discovery Channel that shows them making 70% alcohol - normally in the middle of the night in a hut in the middle of the forest. Guaranteed to get your sight back within 3 days.

[de dee]

I've seen a telly program on the Discovery Channel that shows them making 70% alcohol - normally in the middle of the night in a hut in the middle of the forest. Guaranteed to get your sight back within 3 days.

  in Canada we call it Nufi screech,   USA call it white lightning

[kneeslider]

That possibly cannot be an original belt.

Maybe that is why it is screeching.

[de dee]

  At 22 MM. wide it probabley is bottoming out, on the boss,  slipping on the variator faces

[Snorvey]

That possibly cannot be an original belt.

I didn't see any Kymco logos on it or anything, so you're probably right. OEM parts for me all the way now.

[kneeslider]

The tell tale sign is that original Kymco belts are single sided.

That possibly cannot be an original belt.

I didn't see any Kymco logos on it or anything, so you're probably right. OEM parts for me all the way now.

[Snorvey]

That's quite a tell tale sign! Thanks.

[mousejunks]

My genuine Kymco DT belt says 'Kymco' and 'Mitsuboshi' and is toothed on both sides. Your belt may be slipping since it is too worn out on the inner side, causing it to taper and ride lower in the pulleys. This will affect grip, acceleration and top speed.