49cc belt broke after 6 months

[skyrider]

Hey guys! My 10,000 mile chinese scoot belt disentigrated 6 months ago so I put a new, non Kevlar belt on and 2 days ago it broke. There was a diagonal 2" slice where it broke. Inspection showed nothing unusual to cause a tear except I guess wear so I replaced it with a Gates Powerlink which is supposed to have some Kevlar. Question: Is it unusual for a belt to break like that after 6 months? I did notice that the round metal tube that the belt rests on was jammed into the roller guiding plate cover and I could only get the cover off the tube about 1/16 of an inch. Its really jammed on tight. The roller used to be loose. Does that tube have to be loose, or does tightening the main outer nut with my air gun lock it in anyway???

[kz1000st]

First off 10,000 miles on a belt is really up there. Mine was cracked and gnarly at 9,500 on my 250cc. Second, how many miles did you go in 6 months? A non-descript cheapo belt will only last about 2,500 miles. The metal bushing should be tight on the shaft but semi loose in the variator. The variator floats across it as the weights move out and push the variator towards the fan raising up the belt. Make sure your rollers are in right or the variator will wobble and create tight spots that abuses the belt.

[skyrider]

KZ, I was totally incorrect, the scoot has 10,000 and there were prob 1,000 miles on the belt which was origional replacement, no kevlar. The metal bushing was frozen on the axle and to the back cover plate of the variator. With a screwdriver I was able to separate the spacer/bushing from the back plate by 1/16" but only able to move the spacer by putting a screwdriver between the back of the back plate and the scooter housing which slightly bends the back plate. I was only able to move the bushing 1/16" on the axle when I gave up not wanting to bend the variator back plate.
I did order a new variator kit for $15 off ebay and plan to do whatever it takes to get the spacer out. I still can get out the rollers even with the back plate stuck to the scoot. I'm thinking that no having the spacer/bushing moving caused my belt to break prematurely.

[kz1000st]

You could try heating the variator up with a small torch. Aluminum expands quicker than steel. Yes, if the bushing is stuck that badly it would cause the belt to break. the variator should float freely across the bushing to lift up the belt.

[skyrider]

Just an FYI for me: so the bushing is aluminum and the variator axle is steel so heating the bushing might allow it to expand and slide off???

Also, when it put on the nut after the last time of replacing the belt I used an air compressor and I'm thinking the psi was too high causing the nut to get too tight thus causing the bushing to adhere to the variator and bond tight. My compressor goes to 140psi. Any thoughts on the correct torque psi for the variator nut?? (I may have also over tightened it.)

[kz1000st]

On a GY6 150cc you torque the nut to 45 lb ft. I was told by someone 65 lb ft to be sure with blue loctite. I just did the belt and my stuff was mint from the first belt change. I may use the 45 setting on the next belt change though. I felt like I was a little brutal this time.

[skyrider]

With the help of a hammer and small crowbar between the back of the variator plate and housing, I managed to bang off the bushing without damaging the variator parts. The bushing had actually "shrunken"- my new bushing slid right on, what caused it to shrink??
Anyway, my rollers were shot, so I replaced them, and most of the parts of the replacement variator I bought off ebay didn't fit except for the bushing and drive face fan.
New rollers make a huge difference but I am hearing a rattling of the starting gear assembly on start up and it seems to be barely starting, any suggestions??

[kz1000st]

Someone said the 50cc engines have a Bendix spring on the starters. A lack of voltage from a weak battery or a bad starter could be the cause of your starter problems. I had a 50cc for a while. It would fail to engage sometimes because the battery was suspect.