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Post by greginisn on Jun 12, 2018 23:33:16 GMT -5
I replaced my original 6.5 gr rollers with 6.5 gr Dr Pulley sliders and my performance and driveability went into the dumper, about 20 mph instead of about 35 mph. I put the original rollers back in the my scoot it is running as well again as it did two days ago. Whew!
My question is in two parts.
1 Should I continue to experiment with sliders a little more or just write it off and think they aren't for everybody?
2 Since my experiment with sliders was such a bust should I even consider installing a Polini variator in place of the original one?
2a Does the Polini variator have a greater diameter to help get the somewhat higher speed people claim?
A last note. Before I started this experiment I marked the variator pulley with Magic Marker to witness belt rise on the pulley and with the rollers and it left just about 1/8" mark at the edge of the pulley. I should have re-marked for the sliders but didn't, never expecting such poor results, but the original marks did not get any smaller.
At 20 mph that would be amazing I suppose.
Your advise and knowledge will be appreciated.
Thanks, Greg
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Post by tiny on Jun 13, 2018 6:41:33 GMT -5
From what ive read on these pages in the past i believe your sliders were too heavy.
If the rollers were 6.5g the sliders should have bin 5-5.5g to get the same/better performance.
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Post by humanshield on Jun 13, 2018 7:59:33 GMT -5
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Post by greginisn on Jun 14, 2018 3:39:34 GMT -5
Thanks for the feedback, you have given me hope. In response to tiny & human: Your thinking to go with a one gram lighter slider than a satisfactory roller weight is what I had been thinking so I ordered a set of 5 gr rollers thinking I had it covered. Then I began reading that a 1 gram heavier roller was the answer so I tried just going for an equal weight should give me something to work with. I boosted the 5 Gr slider weight to 6.5 gr and that didn't work out very well at all. I can easily knock the extra weight out of the sliders and return them to 5 gram for another test but I was so bummed out with the first results I had no ambition to spend any more time with that experiment. But since you seem to think my original thinking was correct I can sure try that again with lighter sliders. Thanks. I used this image borrowed from a YT video as an installation guide and it seems to agree with Humans contributions. I think I got the install correct, checked it going in and coming out  BTW the acceleration video tests were very impressive. My scoot ran like it was dragging a bag of rocks behind. |
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Post by greginisn on Jun 19, 2018 1:37:55 GMT -5
Today I got done playing with some other stuff and got back to the Metro and installed my sliders again. First I re weighted them from 6.5 gr to 5.5 gr and then went to work on the scoot. I got the variator off and apart and reinstalled the sliders and making sure, again, they were installed correctly in the variator hub. Final assembly with the Metro is a little more complex than with GY6 Thunder. The outer pulley, the fan and a kind of star washer with the kick starter pawls on it all fit on the splined segment of the crank and if the drive belt is slightly out of position the starter pawl won't spline up and there will be problems. So I had to take special care there and get everything in good position before tightening the crank nut and I got it right the first time. I finished the covering up and went for a ride. It was all good this time. I can't describe how it felt very well but the motor seemed more responsive to throttle changes and I gained a 2 to 3 mph on the speedo. So now I think I'm using all the stock variator has to give. I'd made magic marker marks on the pulley and only about the outer 1/8" still still showed but I'll bet that mark is gone now too due to the small speed increase. The scooter has an RPM limiter built into the EFI box so I'm kind of hog tied there for any RPM increases. So maybe a new Polini variator is in my future? I'm super happy with this mod and must have buggered the assembly somehow the first time cuz it is a little more complex than GY6, but quality analysis is sometimes a difficult thing during frustrating times. I hate to admit that I messed up but I can see no other answer that makes any sense.  Greg |
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Post by GrumpyUnk on Jun 19, 2018 10:25:29 GMT -5
May I suggest grabbing the movable portion of the clutch and compressing the spring when installing the variator? If you do that, and allow the belt to fall into position between the 'walls', it will hold them in position, and give your maximum slack in the belt for easy assembly of the variator bits'n'pieces onto the spline area of the crankshaft. The belt should stay in place, pinched, while maneuvering the variator parts.
tom
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Post by greginisn on Jun 19, 2018 19:26:37 GMT -5
May I suggest grabbing the movable portion of the clutch and compressing the spring when installing the variator? If you do that, and allow the belt to fall into position between the 'walls', it will hold them in position, and give your maximum slack in the belt for easy assembly of the variator bits'n'pieces onto the spline area of the crankshaft. The belt should stay in place, pinched, while maneuvering the variator parts. tom  Is this the part of scooter maintenance where the mechanic needs 3 or 4 arms? I've got a "wonder bar" with tape on the sharp ends that make a perfect tool for opening the clutch pulley. There is just no way I can see to grab that with both hands, not enough gap to the rear, top or bottom, and I can't manage it with only one hand. Getting old is a bitch! Great idea tho. Greg |
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