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Post by jimd8283 on Jul 31, 2015 17:43:19 GMT -5
08' jmstar 139qmb
100cc BBK
I've been working on this scooter on and off for the majority of the year, I've gone through a couple BBK's trial and error dealing with oil leaks and loss of compression. Finally I buckled down and replaced the top end again with a new BBK. Now I got my scooter starting no problem. Fires right up and roars. One thing I never replaced was the transmission. Now after replacing a few things I've had nothing but troubles.
I replaced the original clutch with a new clutch. And replaced the variator with a performance variator that came with my original BBK. With new 8gram rollers. Ever since I've had 3 belts break, 3 fans melt and break. And I can't seem to get it to not overheat. I started the motor and ran it on the center stand for a short time and came to the conclusion that my new clutch seems to produce a lot of heat. And the flywheel seems to wobble a bit within 1/16". Since I figured the clutch was the reason for overheating, I swapped it back to the old clutch. That seemed to not run as hot but it's still not performing as well as it used to. I used to be able to get close to 50mph, and now I'll be lucky to get to 35. It just seems to be dragging in the transmission. Like it could push faster but the transmission is dragging.
I was thinking about replacing the whole transmission. Thinking the problem was with mismatched parts. But I just feel as if I buy a new kit I will have the same problems. With the scooter on the center stand and the CVT cover off I can run the engine up and down and it seems to variate okay. But with a load (me) it just doesn't want to go.
I've already spent over $100 on belts and clutch ( which over heats more than the original) do I have to buy a whole new variator and clutch kit? I've already put more $ than I needed into this scoot
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Post by katastroff on Jul 31, 2015 18:14:53 GMT -5
You could vent your CVT cover. Did you check if both variator and front pulley were aligned? You say you got 8gr rollers, what contra spring ave you got? You could achieve a similar setup with a light rollers/softer contra spring. That would minimize the stress on the belt and the engine. Your new clutch, is it just another OEM one of an after market one? Edit:  |
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Post by Fox on Jul 31, 2015 19:34:45 GMT -5
I'm thinking it might be good to remove the belt cover and the starter bendix and start the engine with a drill/socket. Then you can see what's going on in there when you rev it on the center stand. You might be able to see which pulley the belt is slipping on.
What variator did you buy?
Is that new clutch a standard factory replacement or something else?
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Post by niz76 on Jul 31, 2015 21:53:56 GMT -5
WELCOME!!! You will come to find that there are many things to be tuned in your transmission- roller weights, clutch springs, contra spring, etc. etc. Just buying something new and not knowing how to tune it correctly will prolly just make your wallet lighter without necessarily improving things! Just think of all the $$ you coulda saved if you were here before the first BBK  You're in the right place! |
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Post by jimd8283 on Aug 1, 2015 1:54:03 GMT -5
Okay. So a little more depth. I don't know exactly what type of variator it is. All I know is it's a "performance" variator, when I first bought this scooter last year it didn't run. I took it to a shop and they talked me into buying a BBK that was about $200. Me, not knowing anything about engines or scooters at the time said go right ahead. I know nothing about the original kit. It was supposed to come with everything to make it go. As far as I'm aware of the kit came with, piston, rings, cylinder, valve, rocker, exhaust pipe, muffler, carburetor, variator, rollers, cdi, ignition coil, and few other odds and ends.
Now they got it all put together (except the variator) and it barely wanted to start, but we got it to fire, so I split. It did about 40 so I was happy, drove it around for a few days until one day it just lost power and shut off. I brought it back to them and they said, must be a lemon. So I decide to take it upon myself to become gy6 master. I search all over the internet, forums u name it. I know it now. So I come to find out it had an oil leak in the valve cover. The gasket was flat and oil leaks out the bottom.
So I invest in a whole new BBK ( just piston, cylinder, valve ) installed myself. Ran. Didn't replace the valve cover gasket. Just had to add about an ounce of oil a day. And kept up on it. Then over time it didn't want to start. I'd have to crank it over and pump the throttle, Then my solenoid went out, replaced it, then starter, replaced it, then voltage regulator burned out my tail lights and headlights, replaced it. Found out the problem with that was adjusting the valves. Did it. Ran again. Even better it did 45-50. Well over time I scrwed up and was in a hurry. Forgot the oil and it burned up another piston. Then I parked it for the winter.
Long story.
Spring time. New BBK. Installed myself. Replaced the gasket on the valve so no oil leak. Cleaned out the carburetor. Ran great for awhile. Rear tire popped. Replaced it. Well one night I was out driving. Stopped in a parking lot. Added a little oil. My dumb as forgot to put the oil cap back on and drove it for about 20 minutes before heading home. Went to go leave again and realized I forgot the cap. Smacked myself on the head and said dumb as. Took the car back to the parking lot. Got my cap and headed home. Filled back up with oil. And it ran. But not as great. Then one night the cdi went out. Pushed it home about 2 miles being it was 3am and my wife didn't answer her phone. Replaced it.
Now here we are in the summer. I recently ordered, BBK, piston, cylinder, valve, cdi (no limit) ignition coil, spark plug. Clutch (stock) ( started hearing rattling in the cvt) And a new belt. My original was starting to Frey. Installed the new bbk, roars.
Now I remember, hey I have that variator still. So I got a buddy with an impact to help me out. We put on the new clutch (which I think may have gotten damaged on accident, but I'll get to that soon) new belt and the variator with new 9gr rollers ( came with the BBK) started it up and drove it home. It seemed to drag a little compared to how it drove before but I blamed that on the clutch pads wearing in. Then next day drove to work and noticed a rubber smell and my CVT was hot. Pulled the cover off on lunch and seen that the belt was all melty looking. Put the cover back on and went back to work. On the way home the fan actually melted and fell off and then the belt snapped. Pushed it home about a mile and parked it and got online to learn about these transmissions. And ordered a new fan and belt.
Long story, My life.
Parts came in. Got the new fan on and new belt. Drove it. Same thing. Fan melted, fell off and belt snapped. Super discouraged at this point. Ordered 2 new fans and a new belt. Got it all hooked up and was really paying attention and checking it every few blocks. Noticed the clutch was hotter than the variator. So came home and went to pull the nut off the variator to remove the belt and bam the nut froze. Won't go back on. So I spun it on an angle completely grinding off my threads and took it apart. Sad day. I just rebuilt the engine. I don't want to replace the crank. Well a buddy of mine say's maybe we can rethread it. So we got that done ( lucky me, super excited) well got it home. Put it all together and started it up. Nice. Well as it was running. The nut fell off and snapped all my fan blades off and the variator disassembled and ground up my 9gr rollers.
Scooped up all the pieces and put the variator back together with some new 8gr rollers. And my other fan. Hit the nut with the impact real good and fired it up. Same thing. Nut fell off snapped all the fan blades off. Didn't hurt the variator or rollers this time. Thank jeebus. Pulled an old fan off my bro's parts bike and put it all back together with some white thread sealer on the nut and waited a day. Next day fired it up. But stayed on. Well I notice that while I was running it with the cover off that the new clutch seemed to wobble a bit. So I pulled it off and put on the old clutch and took it for a drive. Seemed to go okay. And the belt didn't snap. I think I may have ran over that clutch at some time causing it to b bent a little. That's why it wobbles.
Now it goes. But the belt I have is melted looking and I'm running the old clutch. It doesn't seem to over heat as much as the newer ( possibly damaged ) clutch. Now as for venting the cover. I haven't. What I have done was built my own cage fan that I cut out of my kids toy and have that blowing directly into the air intake of the CVT cover. It blows in cool air and pushed the hot air out the other end. It actually works really well. But runs off D batteries. I need to wire in a resistor to hardwire it to a toggle switch. But the cage fan cools it down in a hurry. I can get a few pics of my stuff tomorrow in the daylight
Told you, long story...
Also. Just ordered new variator kit, clutch, and belt today. I'll probably see that mid next week
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Post by jimd8283 on Aug 1, 2015 10:16:19 GMT -5
To answer a few questions:
I don't know the type of variator.
I don't know how to tell if the variator is aligned.
The clutch is just another stock one.
I bought the clutch about a month before I installed it.
I may have accidentally ran it over with the scoot pulling into my workspace ( not sure )
I haven't vented the cover, made a cage fan for forced air cooling
Clutch springs and contra springs are stock
And I have ran it with the cover off... It seems to shift okay with no load.
While I was driving last night I could feel a vibrating coming from the CVT. Which may be caused by the belt stretching and rubbing. Maybe.
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Post by Fox on Aug 1, 2015 10:33:50 GMT -5
clutch pads slipping on the clutch bell
belt slipping on the pulley(s)
sticky torque driver not opening and closing smoothly
I had an experience where the seals on a clutch torque driver failed and all the grease inside flung out and got onto the inside of the clutch bell and the clutch pads. Needless to say the clutch was slipping and heating up but the thing that was most interesting was that it heated the belt up and the belt transferred the heat to the variator and melted the fan and even partially melted the weights.
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Post by jimd8283 on Aug 1, 2015 19:39:06 GMT -5
The whole CVT is dry. It has a bit of rubber dust from the belt wearing. But while the cover is off and on the center stand it seems to shift okay. First clutch engages, then variator compresses. Then letting off the gas, the variator decompresses then clutch. Seems to work okay. The old clutch isn't seeming to get hot. Just the new one. I don't expect it to grip well anymore because the belt is smoothed from getting hot. New parts otw. Hoping to go fast again.
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Post by jimd8283 on Aug 1, 2015 21:17:10 GMT -5
Okay. So put the old clutch back on and went for a drive on a cold engine. Took off pretty well. I'm pretty sure the overheating was coming from that newer clutch. Seems to work okay with my old one. Maybe with a new belt I'll be hitting top speed again! Now my next question. Is there much of a difference between a performance variator and stock? Maybe just quicker take off. Idk. But I ordered a new variator and clutch and belt. Should I just stick with the performance variator I have installed? Or should I just put on all new parts that I got coming? My scoot seemed to drive well enough with the stock variator before.
I'm running a stock clutch. Would the performance variator ruin my stock clutch?
Maybe just some 6gr rollers could boost my take off. But would it lower my top speed? I think I've read in the past that it doesn't. I've never had a problem with keeping up with cars off a red light. And I'm 340lbs! I'm not trying to be the fastest. But the reason I stick with the bbk is for power to push me around..
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Post by scooterpimp on Aug 1, 2015 22:59:18 GMT -5
Replace everything , 5-6 g rollers/sliders will help takeoff. Dont take this the wrong way , but 8g rollers & 340lbs are pretty taxing on a 139qmb..  5-6g rollers/sliders & about 1500rpm clutch springs. Should improve takeoff/launch .get a good belt. (Bando etc) cheap belts wont last.. |
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Post by jimd8283 on Aug 2, 2015 1:38:09 GMT -5
No pence taken. Most of my weight comes from height. I'm 6'8" 340. Ppl think I can't be more than 280-300 at first look. Lol. I think I will just put all new on it. I'm going to order me some 6gr rollers to throw in there too. But overall I think I solved the thread problem. It was the clutch that was overheating, because after putting my old clutch back on, even with my belt looking melted and starting to frey I've gone about 25 miles.
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Post by scooterpimp on Aug 2, 2015 11:19:28 GMT -5
Holy cow! 6'-8" & 340lbs. You can use 2 scoots as rollerblades!  |
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Post by jimd8283 on Aug 2, 2015 20:43:35 GMT -5
Pretty much. Lol. Almost think I should switch to a motorcycle. But I love my scoot!
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Post by insanepuppydog on Sept 16, 2023 21:20:19 GMT -5
What kind of grease are we using for this I went to pull the cover off belt melted and so did the variator fan but we had a belts snap first and variators fail I keep thinking maybe the bendix is to loose in it bushing b4 I saw it this time the melting I kept getting frustrated how to keep clutch from heating up also there is another bearing looks like I can grease it I know u can on the needle bearings I am wondering if that was creating the heat or maybe the clutch just needed to be replaced which we just replaced the belt the bendix the clutch and finally the dr.pulley 5g sliders now wants another new variator what the heck.is going on with this and yes going to be drilling holes in the kick start cover for more cooling I am just like wtf getting tired of it he has the great naraku 52.4 mm bbk he had one b4 where we where going through brand new cranks like every 6 months he is learning what to do i did putba 150cc carb and rejetted it runs great please help [quote author=" Fox" source="/post/191976/thread" timestamp="1438443230"]clutch pads slipping on the clutch bell belt slipping on the pulley(s) sticky torque driver not opening and closing smoothly I had an experience where the seals on a clutch torque driver failed and all the grease inside flung out and got onto the inside of the clutch bell and the clutch pads. Needless to say the clutch was slipping and heating up but the thing that was most interesting was that it heated the belt up and the belt transferred the heat to the variator and melted the fan and even partially melted the weights. [/quote] |
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You're in the right place!