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 qmb139 belt difference

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ldrancer
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Join date : 2013-06-09
Age : 44
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PostSubject: qmb139 belt difference   qmb139 belt difference I_icon_minitimeFri Oct 16, 2015 1:11 am

found out something weird. i had an old qmb139 at one time, until it got stolen off my front porch. anyway, once the belt broke, i could never fit another belt onto it. i was on a chinese scooter forum at the time and asked about it, becuase the belt wouldnt reach over the front part after putting it around teh back part. the guy there 90gtvert, told me, just squeeze it inbetween the rear and get it on....

ok ill tell the story of what happened. my belt broke. no numbers, so i figured and everyone else said too, and this is all i could find, was tht it was a 669-18-30 belt. , thats the belt i thought I had to get. after buying a kevlar mrp-speed belt online and waiting on it to show up, instead of buying another belt off the guy I bought my chinese 49cc scooter from, who he thought he had 669-18-30 belts too and thought thats what the bike used, he had some no numbered belts. and that comes into play in the story later.. i got the kevlar belt online. i needed a tool to take my variator bolt off with. i went up to the wal-mart and found an electric impact car cigarette lighter impact wrench for 30 bucks and brought it back. well, we got the front bolt off, then needed to put the belt on there. the old belt, just slid over the front. it just, fit. this kevlar belt, wouldnt go over it. we pulled and couldnt get it to wriggle over the front, drive boss on the front side, part. it wouldnt get over the crankshaft arm.

i went down the road in my car to the gas station, for some smokes or something and while i was gone, my cousin who was helping me, part indian guy, had took a hammer and stuck it inbetween the rear pulleys, to pull them apart, and go the belt to go down in it, then was able to get the belt over the front. he told me he got the belt over the front by using ahammer to pull the two rear pulleys apart. we tried to use our hands but we couldnt get no pull on it, both of us, i think he tried to. couldnt get much pull, and the stretch on this belt to get it to reach over, was pretty far. it was a tough built belt. and by measuring the outside length with some cloth measuring tape, out of all the 669-18-30 belts i checked, it was the shortest. they all though, let me put that measurement here, they measured at the shortest, 26 9/16" and at the longest, 26 15/16". one even seemed to go a hair but not to 27, over it. you could tell by putting them side by side and matching them together then seeing the other one stick out further which belt was the longest.

anyway, we got that belt on there, and i noticed the belt, diggign down into the rear pulley, quite far, and i thought, well, i guess this is how it goes. itll work. i had heard that trick to pull the rear pulleys apart, but I thought thats stupid because they got a big spring in there and they want you to stick the belt in it? its like a mouse trap they want you to spring and use the belt for holding it open with or something, instead of letting it work the way its supposed to. anyway, so i done it the way id heard people do.

so i put the variator nut back on and went for a ride. down the road and back. not far. didnt ride hte same, at all. i took it back apart and said no, im not goign to use this. this isnt working.

the guy i bought my scooter from, had told me he had a belt but was on vacation and wouldnt be back until the end of the week on friday. i figured id just go to him and buy a belt off him. he got back and i took the belt i bought to show him. we compared the belt and you could tell, the other one was way more curved out and bigger. much bigger.

so i got that belt, and broght it back. i put it on my scooter, and no pulling or anything.

too late, i took it for a ride, 3 miles later, waaaammm snaaappp. broke belt. i was mad. got a ride back, and found out what was wrong. the rear driven pulley, had blown it's seals when i crammed that belt down in the back of it, and road it down the road.

anyway. after that, i replaced the driven pulley. tried and tried to get belts. i asked on that forum from that guy 90gtvert who said, just cram it down in the back, i said what am I supposed to do, it just broke my driven pulley? i cant fit a belt to my bike? i didnt know what to do, and i mentioned my driven pulley had broke from the too tight of belt the oil seals where shot. he said, I don't know. that was it.

anyway, so i found a guy who had the same bike as me, on a forum. i asked him since he had his variator and belt off and stuff, if he'd measure his belt for me, since i was having trouble getting one for mine. he measured it and told me, it was 27inches long.

I went out after that and got a measureing tape. and I measured every belt I had and every belt I could find. The one the guy I bought my bike from I bought off him and broke, I couldn't measure as I'd already broke it, before I measured any belts. But a guy with my exact bike measured his, and I knew what i had to shoot for.

I drove 100 miles away, looking for a belt. I measured, all kinds of belts. at scooter shops, at moped shops. not many around here. I measured those green striped 669-18-30 belts. I asked people if they had anything else. noone had nothing. the most common measurement i got was 26 5/8" or 26 3/4" when they where loose like type. 26 and 19/32's was the closest to anything tighter besides the mrp-speed kevlar I had. Thats, 1/32" shorter that 26 5/8" inches. and 1/32" inch longer than 26 9/16" inches. The longest i measured was a hair over 26 15/16"

i ended up getting 2 different belt before I well, gave up and the bike got stolen. i got one from where i drove to. it was a little under 26 15/16"s big. ok, well, maybe even, 3 belts before. anyway, that belt 26 15/16 a little under how long did it take before it broke? i bought a new driven pulley. it took like, 14 miles. good thing i was right next to a cousin of mine and could just push back 200 yards to his house to ask him to get a ride. I was out that day and had a lot of places to go.

I think I might of tried another belt, one time i went out riding, and I think my variator broke on me. actually I think it broke that time 200 yards from my cousins. and thats what happeneed, but it also broke the belt too. the too tight of belt, was pulling on the variator against the ramp plate, and broke the plastic slide guides, and was digging a ditch into the variator bar there, that the ramp plate has its slide guides go up and down. where they travel up and down. They would eat that ditch, and break those slide guides, and stay stuck in there. And ride up and down in that ditch, until they ate through the variator, then boom. The variator would spin around the ramp plate, the rollers would get caught on something, and boom, the belt would get snagged, and break. You'd be stuck, and the variator wouldnt be worth crap.

After this, I knew no belt unless it was big enough would work. So I went to the guy I bought my chinese scooter from, and asked him to see his belts so i could measure them. everyone was 26 5/8 to 3/4 inches big around. I knew they coudlnt work. I asked him if he had an old belt laying around. They said yea, they had one bike, they had 4-wheeled pretty much on and gave it crap, i could have its belt off it. It was stretched and part of the strap on the back was gone. but it still looked usuable. as long as i didnt try any big hill pulling with it. Oh, when asked the guy I bought that scooter from that I couldnt fit the belt it was too tight, what to do. He said, did you adjust it..? stupid. theres no adjustment on a scooter belt. it didnt fit.

I went and bought a new variator since I'd blown my other one, online. and used this used stretched belt. I think it measured 27 1/4. my top speed was down like 3-4mph, but i could ride. i rode slowly and took off slowly, up and down the road on it, for about 600 miles. then i went, I cant keep riding on this belt. It didnt get worn too much more, but I was afraid it'd snap. I went to hunt down the biggest belt I could get.

long story short. went to where I bought the qmb139 bike at. went through his stock of belts. found the longest one I could find. 26 15/16" and a hair bit longer. figured, this would work.

let me explain how it went on. I had a brand new variator only used on that stretched belt. it had no problems. I had a new driven pulley. When i went to put that belt over the crankshaft arm, and the drive boss, I had to pull pretty hard, like it didnt fit. I pretty much wriggled it over, and hard every bit of the way. had to force it on. but it fit. it would dig the rear driven pulley open, just a bit. i rode it down the road for about a 35mile drive. I came back, and I took the front variator nut off, and checked it. and the plastic guides had been broken and cracked off, and the ramp plate was digging a ditch, into the variator walls. i knew it wouldnt work. it sat, parked until it was stolen.

Well, I always thought it would of worked, and it would of, if I could have gotten a belt, that was bigger and about the same kind of belt. something a little bit longer length. other measurements, like close or whatever or something.

see the 669-18-30 thats, x-x-x the first x is the length, measured by the inside, the second x is the width, in MM's, the 3rd x is the angle of the v's cause it's a v-belt. it's their angle.

Well, later on, I'm searching through a site, looking at belts. think about that chinese scooter i needed a belt for, and there IS a 681-17.7-30 belt. !!! AAAAAAAAHh

that would of worked, nd its for the qmb139, theres 3 different covers for the kicker on them and there are 3 differnt versions. and thats the belt. thats exactly how much extra i needed to fit that belt on there.

anyway, if you cant fit your belt on your qmb139 49cc chinese scooter, or anything without an oem maker, and your tearing crap up, if you got a 4-stroke qmb139 and you think you need a 669-18-30 belt, but it wont go up on the crankshaft arm or the drive boss, of the variator, either one, then get a 681-17.7-30 belt.

if your space is real big and thats not even close, theres a long qmb139 belt too. like real big, 700something number. i knew how much my 49cc chinese scooter needed, and it wasnt that much.

I'd look online at part numbers and lengths of belts, and about the time they'd get to 669-18-30, they would go up in size by the first number, the next thing you'd see would be, 700's numbers.

anyway, if your qmb139 belt, you think you need a 669-18-30 and its too tight and your breaking crap, replace the broken crap, if theres any ditches dug in your variator, replace it, the ramp plates will tend to want to ride there and dig the ditches deeper and break the slide guides until it tears it up and you lose the belt. check your oil seals on the driven pulley part. and try a 681-17.7-30 belt. they make them
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bignut
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PostSubject: variators   qmb139 belt difference I_icon_minitimeFri Oct 30, 2015 1:24 pm

so I installed the variator pulley spline in the nut shaft turbo, bearing balls. THen I turnde the small spline end wobbly if and what the belt area on the wheel diameater?

i then yo uno what I said on the intake boost port window bearing?

No you don't know I went speed choke heat up plug sparer caps.
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ldrancer
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PostSubject: Re: qmb139 belt difference   qmb139 belt difference I_icon_minitimeSat Oct 31, 2015 12:38 pm

bignut wrote:
so I installed the variator pulley spline in the nut shaft turbo, bearing balls. THen I turnde the small spline end wobbly if and what the belt area on the wheel diameater?

i then yo uno what I said on the intake boost port window bearing?

No you don't know I went speed choke heat up plug sparer caps.
thats a good post.  but, shouldnt you be keeping that over on totalruckus where it belongs?
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PostSubject: Re: qmb139 belt difference   qmb139 belt difference I_icon_minitime

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