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Post by dev150cc on May 14, 2014 0:18:36 GMT -5
I had the variator cover off recently doing a PDI on my scoot with 3000 miles, new to me. I was pleased to see someone had installed a Gates Powerlink 743 belt and it was is good shape. Spec'ed the width at a tight 19mm, which should be good. Checked for cuts or other compromises, and gave the variator and clutch surfaces a feeling over for smoothness. A-ok. Rode the scoot to work yesterday 25 miles away. At 24.75 miles, the belt went - surprise! Tonight, I bought a electric impact wrench (my 6 gallon air tank won't pump an air impact wrench enough apparently) and made short order of removing the clutch and variator. Clutch looks fab, I'll just do a clean-up on it and re-install. The variator was a different story. I got the clutch off and pieces started falling out. Come to find, one of the roller weights had begun to disintegrate. See the one on top. Plenty of flat spots on the others as well.  I already have on order a Koso variator from nycscooters and had them include 12g weights. I *was* going to compare them to the stockers, but that plan is out the door. I have a theory that the belt shredded because a piece of that roller got out and nicked the belt. Could just be coincidence though. Dumb question of the day (I'm entitled to one as a scoot newb): With a belt off, the variator assembly will be a bit "loose", correct. That is the ramp plate, rollers and variator itself will not be sprung because they are in a neutral position, yes? I was surprise, but shouldn't be, that it felt a little jangly when I took a moment to inspect it after the belt broke. Thanks all. Hope someone benefits from my experiences. |
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Post by tvnacman on May 14, 2014 8:13:05 GMT -5
I would suggest opening up the clutch assembly for a good cleaning . Lube the area where the pulleys slide and pivit points . Use grease thst will not liquifie when hot . When your putting everything together at each step be sure there in no binding or tight spots . Lightly grease the shafts and splines . Grease the clutch needle bearing squish all the old grease out eith fresh grease .
Your welcome to call if you need/wwant to .
John
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Post by dev150cc on May 14, 2014 10:26:22 GMT -5
Hi John, thanks for the info. Yes, I pulled the clutch off and will open it up to check it's condition as well and clean/lube.
I appreciate the fast turnaround on my variator order. It will be here just in time for me to button it all back up after a property clean and inspection.
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Post by JerryScript on May 14, 2014 11:09:59 GMT -5
Yes, with no belt your variator assembly will be loose. In fact, it will be loose enough to let the weights fall out. It's possible the belt failed, and the resulting looseness of the variator assembly allowed that broken weight to turn sideways, which then could have cracked a portion off. Sometimes after breaking a belt all the weights will fall out.
Be sure when you install your new variator that you hold the ramp plate tight against the variator face while sliding it all onto the boss/crankshaft.
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Post by urbanmadness on May 14, 2014 11:52:01 GMT -5
Those wieghts are trash!.... Make sure you don't have any belt particles in the clutch..... Usually when they go, they desinagrate and get into everything! Last one I broke, on a 150... the biggest piece of belt left was about 2" long. Much, much fun  |
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Post by dev150cc on May 14, 2014 13:36:07 GMT -5
Thanks for confirming you guys. It mechanically made sense, but it always pays to have someone validate your thoughts.
I measured my bad rollers - 18 grams down to 14 grams for that munched one. Total 100 grams. Going to 12 or 13, or a mixture, will put me in the 72-78 gram vicinity.
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Post by tvnacman on May 14, 2014 15:11:42 GMT -5
Hi John, thanks for the info. Yes, I pulled the clutch off and will open it up to check it's condition as well and clean/lube. I appreciate the fast turnaround on my variator order. It will be here just in time for me to button it all back up after a property clean and inspection. I try to get them packed and on the way asap . All you need to do is ask here seems like someone is always home here . John |
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Post by dev150cc on May 14, 2014 15:14:10 GMT -5
Thanks. According to USPS, it's already on its way and will be here tomorrow. The diligence is appreciate nonetheless.
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Post by dev150cc on May 16, 2014 2:53:46 GMT -5
Ok, I cleaned everything out, including disassembling the clutch assembly and servicing it.
I installed the Koso variator with the 12 gram rollers (the originals measured 18 gram on my work scale - probably 17 but the scale only registers even numbers).
I installed the new Gates Prolink belt as well. It all went together smoothly.
Lost bottom end umph but gained quite a bit of top end - maybe 5-7mpg. I don't have a tach installed yet, but the RPM's are substantially lower at WOT. A lot lower. After about 10 miles, it started hesitating and cutting out. I think it was overheating. The outside temperature was around 78, so not too hot. I limped it home as it gradually started losing power - wasn't sure I'd make it home.
I noticed the CVT cover was fairly hot. I let it cool down a bit and took the cover off. I was expecting something bad, but nothing was out of place. I forgot to sharpie the pulley.
So to summarize:
Short 150cc GY6
215 pound rider
ambient temps 78 degrees
Orig rollers 17g and I was topping out at about 50mph and felt the engine was getting toward red (no tach). It had decent jump off the line in original form.
After Koso variator and 12 gram rollers installed:
Topped out around 60 indicated (was happy about that). Substantially lower top RPM - very noticeable, maybe too low?
Lost quite a bit of bottom end, but I was happy with the topend tradeoff
Oveheated engine I think (or something that felt like that, including progressively cutting out if I pushed it)
I'm at a loss. Ideas? I'll start by checking the plug tomorrow. *edit* I looked at the plug this morning and nothing notable, looks ok.
I have 13g rollers on order but won't be here for a few days. In the meantime, I may try my stock variator with the 12g rollers.
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Post by JerryScript on May 16, 2014 12:06:02 GMT -5
When you checked your plug, what color was the porcelain inside the threaded area? If it's white, you are too lean, and that does cause overheating, and can lead to engine damage/failure. Your plug needs to be a coffee color.
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Post by dev150cc on May 16, 2014 12:16:29 GMT -5
Yeah, plug is a healthy toast/slight grey. Not rich, not too light. I thought maybe it was fouling out at the time, as that's how it felt, but no, it's good.
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Post by tvnacman on May 16, 2014 12:17:24 GMT -5
Make sure the black engine shroud is in good condition , no cracks or separated parts . Be sure the filter screen for the cvt is not blocked . Check your valves and plug . Jerry is on point there .
Rpms would be helpful .
John
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Post by dev150cc on May 16, 2014 12:26:11 GMT -5
Everything else is in great shape. Just checked the valves last weekend and it's spot on. It would be coincidental, but I'll check all vacuum hoses to make sure I didn't accidentally pull something off when I was working in there. Other than that, I'm at a loss.
I'll get the tach on this weekend, and sharpie the pullies. Just don't want to risk burning up the engine testing things out.
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Post by tvnacman on May 16, 2014 12:36:08 GMT -5
That belt sounds short for a 150cc .
John
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Post by dev150cc on May 16, 2014 12:45:25 GMT -5
As far as I've seen, the 743/20/30 is the stock belt for a lot of short case gy6 150's. It is the size of Gates that was on previously as well. As I recall from hours of scouring various forms, the short engines don't have much option to increase belt size.
And I could be wrong - perhaps the engine wasn't overheating, but the symptom was increasing stuttering the closer I got to bringing it home. Maybe belt slippage? I had to carefully feather the throttle on those last couple of miles home just to keep smoothly rolling at a lower speed. I know it could be a dozen different things coincidentally going south at the same time I'm performing this maintenance. Tack readings and getting a sharpie marking on the variator travel will help there as a first step.
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