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Post by pdough on May 26, 2011 9:20:16 GMT -5
this one has me stumped. a few week ago i tried out a racing clutch and yellow torque spring, with new belt. i didn't really notice any real performance boost, this bike has 72cc kit. about
50 miles or so later the belt snapped. so i thought the clutch and spring were to blame, so i put back in old clutch and old torque spring, with the old belt, ran it for 50 more miles and noticed that the old belt, which was still good when i put it back on, was now all chewed up. so i went to the scooter part store and got a new belt, 50 miles later the bike quite running, i pulled off cvt cover and the belt was upside down and all chewed up again, and i have no idea why. for my rollers i have 6.5, 8 , 6.5, 8..... the clutch pulley looks clean, nothing in there to eat up these belts, i sure could use some help with this one
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Post by 90GTVert on May 26, 2011 11:14:30 GMT -5
First off, make sure you use good belts like Bando or even Gates. Bando is my favorite so far. The ones that are the cheapest Chinese stuff don't hold up that well. I went through a bunch of belts on a couple of my scoots after buying some cheap Chinese stuff and after a lot of thought and trial and error trying to see what was wrong I switched both to Bando belts and that was the end of the problems for me. While you are in there, I'd take apart the torque driver and clean and re-grease it and make sure everything in the vari is in good working order. Check the bearing in the torque driver where it rides on the primary shaft for the gearbox. Also make sure that shaft turns without noise or grinding. Get all fo the belt dust out of there. In the process of all that cleaning and inspection you should notice if anything is awry. One thing I like to do, though a scooter should be OK without it, is venting the CVT cover. It will help the heat escape a little better and perhaps help CVT components last longer. Might be helpful... 49ccscoot.proboards.com/index.cgi?board=transtech&action=display&thread=35749ccscoot.proboards.com/index.cgi?board=transtech&action=display&thread=360 |
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Post by speedy1125 on May 26, 2011 11:26:40 GMT -5
do you have a complete variator in there? and assembled right? hmm.
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Post by pdough on May 26, 2011 15:06:38 GMT -5
yes i do have a complete variator in there, however on the last go round all my rollers were cocked sideways when the belt turned upside down. now i have another question my factory belt had the markings of 729/17.7/30 and the bando belts i found say 723/17.5/28 are those two belts the same, because the cheap belt i bought had the same markings as the original.
also your right about venting the cvt, I'm not sure if i have bigger problems or not, but my cvt cover gets so hot, you cannot touch it. I'm not sure if thats normal or not, but i know i gotta find a way to keep it cooler. thank you Brent for all your help and wisdom. another question; is there anyway i have the nut that keeps the clutch together on there too tight? i used the old c clamp, screwdriver and hammer trick to take it on and off. when i put it back on i tap it tight till it wont go any further. also do you think having the 6.5, 8 gram rollers might be a problem?
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Post by 90GTVert on May 26, 2011 21:45:18 GMT -5
You should be able to use the 723 Bando. It should be 6mm shorter, .2mm more narrow, and 2 degree difference in angle. Should be OK.
It's normal for the CVT cover to be very hot if it's not vented. Sometimes they get pretty warm even after being vented.
I dunno if you can over tighten a clutch nut and cause something like this?
Staggered rollers shouldn't be the issue. Lots of us do that without issue.
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Post by speedy1125 on May 27, 2011 5:15:18 GMT -5
Personally I feel your belt is too short. I have 2500 miles on my gates (500 of that with a 83cc) and its not showing hardly any wear.
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Post by rocketdog on May 27, 2011 18:03:42 GMT -5
The belt turning over thing makes me wonder if the variator and the torque driver are lined up properly. Put a straight edge on it and see if they are at an angle.
RD
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Post by pdough on May 27, 2011 23:07:39 GMT -5
I had thought about that RD. How could i correct such a problem, if it turns out there off? Never had any belt problems before i had clutch and var.off. I will check it
on my next day off
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Post by rocketdog on May 29, 2011 6:56:57 GMT -5
Now that's the question. Since both the Variator and the Torque Driver/Clutch just bottom out against the shoulders of their shafts. If it is off, you could shim one of the offending components. It's more than likely a heat problem or the torque sleeve isn't sliding on it's pins properly. From the factory they rarely have much grease in them and that's China grease. More like bees wax than grease. Venting the CVT cover wouldn't hurt.  RD |
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zedooo
Scoot Enthusiast
Posts: 122
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Post by zedooo on Jun 3, 2011 1:57:22 GMT -5
If you shorten the drive boss on the variator, it can open too much and stress the belt too much (try opening the rear also maybe you solve this problem) - and get to serious speeds too  |
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Post by stepthrutuner on Oct 28, 2011 0:16:25 GMT -5
If you shorten the drive boss on the variator, it can open too much and stress the belt too much (try opening the rear also maybe you solve this problem) - and get to serious speeds too Perhaps you got a little confused (easy to do with cvts) and misstated your case. Shortening the boss limits the opening of the variator and shifts belt travel range outward on the pulleys resulting in less multiplication on start off (which would stress the belt more) and a lower final position drive ratio provided the rear pulleys will open enough to compensate for the extra length of belt taken up on the front pulleys. If the rear pulley will not open sufficiently the belt can heat from the pressure of the roller weights squeezing on the belt at or near top speed. In this case a slightly longer belt will relieve the extra squeezing effect and help top speed. |
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