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Post by xyshannen on Dec 9, 2014 11:17:57 GMT -5
oldchopperguy Thanks for the bone myman! It's in my blood. Dating back to my Florida bootlegger Grand Dad to my Father who was a breakout circuit drag racer on the east coast. When I was 13 we built a riding mower that would run 35 mph and mow our 2 acres of land in about 20 to 25 minutes. The great thing about these GY6 150s is the cost of modding them is so low it's almost a shame to leave them stock. The benefit of having the remaining part of the cover run so close to the open face of the pulleys is you do get "some" protection against road grime and pebbles getting kicked up from the tires. It does have a small risk of something getting stuck between the cover and the belt but that's not very likely to happen in on-road conditions.
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Post by richardv on Dec 9, 2014 20:48:10 GMT -5
A snowmobiles cvt is completely exposed so it's no issue. My 500s belt lasted 10 years of hard riding.
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Post by oldchopperguy on Dec 10, 2014 2:28:58 GMT -5
oldchopperguy Thanks for the bone myman! It's in my blood. Dating back to my Florida bootlegger Grand Dad to my Father who was a breakout circuit drag racer on the east coast. When I was 13 we built a riding mower that would run 35 mph and mow our 2 acres of land in about 20 to 25 minutes. The great thing about these GY6 150s is the cost of modding them is so low it's almost a shame to leave them stock. The benefit of having the remaining part of the cover run so close to the open face of the pulleys is you do get "some" protection against road grime and pebbles getting kicked up from the tires. It does have a small risk of something getting stuck between the cover and the belt but that's not very likely to happen in on-road conditions. I know, I KNOW!
My best saddle-pal, riding buddy, that is... (that might have a different meaning today... LOL!) was a part-time bootlegger. Whew, what adventures WE had! Taught me to handle a 1911, drive a semi, and other things every red-blooded American boy should know... LOL! All my buddies drag-raced, some of them did really well, but with CARS. I was always the black-sheep biker guy... Guess that's what really inspired me to build "Old Blue". I wanted a CHOPPER that would cover the quarter-mile in less than 10 seconds in street-trim... EASY to accomplish on a modern crotch-rocket, but dang-near impossible on a sixties-built, 1957 Harley. My trusty pan-head came close... With me aboard, she got into the low 11's with the occasional mid-10 @ 135+ but my 4' 6" 76-pound gal-friend could crank out mid-nines, near 150 mph all day long... Needless to say, my fearless, type-A female Alpha-dog "Janice, the Flying Squirrel" was my pilot of choice when Old Blue was involved in a big-bucks street-race! She NEVER lost...
Ah, I guess since I weighed 375 pounds (MORE than the BIKE...) she had a major advantage! I don't think in 55 years, I ever really thought about weighing 300 pounds MORE than her, and 20 pounds more than Old Blue... LOLOL!
I agree with you on keeping the shell of the CVT cover, just for safety. It looks good too. And you're right about modding the GY6 150's. They just BEG to be tweaked! It's NOT like you're ruining the value of a multi-thousand-dollar bike. You're IMPROVING a thousand-dollar scoot!
I got about a 5, maybe as much as 7 or 8% increase in all-round performance on mine with simple mods, and made it 99% reliable at the same time. Whomever bought "Lil' Bubba" from MOXIE SCOOTERS when I traded it for my "new" old Kymco 250 "Minnie Mouse" got one SWEET Chinese ride!
My overall favorite "class" of scoots probably IS the plethora of 150's out there. I looked a LONG time to find a 250 freeway-capable scoot that emulated the classic 150. The out-of-production Grandvista is mighty close in all dimensions, handling in slow, tight traffic VERY much like the typical Chinese 150, but when I need to sneak onto the freeway, cruising 70, Minnie feels VERY much like my old Harley baggers did. For anyone wanting to do the same (get a 70 mph scoot that still looks and feels like a Chinese 150) I highly recommend they find a good, used Grandvista. They're affordable, indestructible, and dependable as the family car.
A GREAT combination, but, she ain't no drag-bike! However, she WILL out-run my ''89 Mercury Grand Marquis station wagon...
Keep that pretty leather side up, and the greasy side down!
Leo
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Post by oldchopperguy on Dec 10, 2014 2:44:01 GMT -5
A snowmobiles cvt is completely exposed so it's no issue. My 500s belt lasted 10 years of hard riding. Welcome to the site!
Yup, snowmobiles seem to have pioneered the CVT! Good idea! I guess in Alaska, they insist you call 'em "snow machines"... I have often wondered why I haven't seen anyone transplant a screaming 700cc 2-stroke snowmobile power-train into a scooter! Seems like a natural to me!
Leo in Texas
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Post by rockynv on Dec 10, 2014 8:24:09 GMT -5
Actually Leonardo da Vinci came up with the CVT concept in 1490. Milton Reeves in 1879 applied this to saw mills and then in 1896 put his CVT in his first automobile. Daimler Benz patented their CVT in 1886. Zenith Motorcyle had a CVT in their 1910 Gradua-Gear bikes. In the post depression era the CVT was used in small to medium tractors such as this circa 1950 Bolens walking model of which I still have a working unit with the following three attachements:  Turn soil using moldboard plow with coulter: Plowing snow: With cultivator rakes: |
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Post by JerryScript on Dec 17, 2014 13:08:58 GMT -5
I often have my niece on my scooter, so I am just a bit worried about an open CVT case. You can be ultra vigilante, but on time she lets something dangle is all it takes, and I won't risk her safety.
That being said, I wonder about air scoops built into the CVT cover directly over the variator and clutch, with an vented end. It would take a plexi-glass cover and some smoke during testing to determine the proper configuration for maximum air flow around all components. If a configuration were found that significantly reduced component temps, it could be an cheap and easy modification or aftermarket add on.
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Post by oldchopperguy on Dec 18, 2014 2:17:13 GMT -5
I often have my niece on my scooter, so I am just a bit worried about an open CVT case. You can be ultra vigilante, but on time she lets something dangle is all it takes, and I won't risk her safety. That being said, I wonder about air scoops built into the CVT cover directly over the variator and clutch, with an vented end. It would take a plexi-glass cover and some smoke during testing to determine the proper configuration for maximum air flow around all components. If a configuration were found that significantly reduced component temps, it could be an cheap and easy modification or aftermarket add on. All I did on my Xingyue was to remove the filter in the CVT cover-front (and "baloney-slice" the little intake scoop so the cover was more easily removable) then cut open the cover-face over the clutch. PLENTY of air goes in and through, and it lowered the temp of the clutch and belt dramatically.
To avoid exposing the whole clutch-bell, you could drill BIG holes to "Swiss-Cheese" the cover over the clutch and it would work just as well. No rocket-science needed, just be sure to allow unrestricted air in, and plenty of unrestricted exit back out... and no worries about the little ones getting wound up in the belt.
Big holes in a circle around the clutch area allow plenty of air out, and look professional if carefully spaced. It's a mod worth doing...
Ride safe!
Leo in Texas
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Post by junkyarddog on Dec 24, 2014 23:52:02 GMT -5
I have had 2 belts shred on Yamaha scooters. A Vino 125 and a Zuma 125. The one on the Vino was the third one. I replaced the original at 10,000 miles, and it looked good. I replaced the second one at 20,000 miles, and it also looked good. I also replaced the rollers. Everything stock Yamaha. Nothing aftermarket. at 24,000 miles, the third belt shredded with only 4,000 miles on it, leaving me stranded in the middle of the AZ desert. There was a lot of ground up rubber in the case, and melted rubber on the front pulley. Apparently it has seriously overheated. I had always kept the CVT filter clean, but the Vino 125 has a huge plastic cover over the actual aluminum case cover, which appears to be for cosmetic purposes only. It seems to block most of the airflow to the CVT. I replaced the belt, but never trusted it again. I sold it at just over 26,000 miles. Most of those miles were at full throttle on the open road, and I weigh 240, so some might call that abuse. But why did the first 2 belts do so well?
I replaced the Vino 125 with a new Zuma 125. The Zuma is much easier to replace the belt on, you don't have to drain the bike and remove a ton of parts. That turned out to be a good thing, because the belt broke at around 7,000 miles. That was the original belt. This time I had a spare belt and the tools to replace it. I rode it back home, put it on Craigslist, and sold it.
I now have a new SYM HD200, and a spare belt. I have a little over 3,000 miles on it, just checked the belt (super easy to get to it, Yamaha could learn a few things from SYM) and it looked good. I will replace it at the scheduled intervals. If this scooter shreds a belt, I will probably give up CVT scooters. My '09 2 stroke Genuine Stella may not be the most reliable thing on the road, but at least it does not have a belt to break.
Which brings me to my other issue with CVTs. They have a very narrow gear ratio range. They are geared for top speed, which is fine on level roads, but small displacement scooters like a 125 simply will not climb. They do not have a low enough gear ratio. You cannot keep the rpms in the powerband. Where you would normally downshift on a manual transmission bike, a small CVT scooter just bogs down a lugs the engine like crazy. Both my Yamaha 125s would slow down to about 15 mph, and make loud knocking rattling noises, just like you were trying to ride a couple of gears too high. I even put a clip on inductive tachometer (made for a Jr dragster) on the Vino 125. At top speed on a level road, it was spinning near 9000 rpm. But climbing a steep grade, the rpms dropped to about half that. My former 2 speed Tomos moped would easily climb hills that stopped the Yamahas dead in their tracks, and with about 1/4 the power. All because it had a super low first gear.
So I would not only like to see a more durable CVT, but one with a much wider gear ratio range. A high gear for cruising on level roads, and a really low gear, for climbing steep hills and riding in mountains.
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Post by JerryScript on Dec 25, 2014 15:39:01 GMT -5
junkyarddog: You might want to try replacing your roller weights with sliders, and a larger variator too. The larger variator will take advantage of a larger RPM range, and sliders give you both better torque at low RPM, and higher top end. You say you hit 9000 RPMs? You should probably try some lighter slider weights, 9000 RPM is redlining, and that alone could explain your belt failures.
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Post by junkyarddog on Dec 30, 2014 21:09:50 GMT -5
junkyarddog: You might want to try replacing your roller weights with sliders, and a larger variator too. The larger variator will take advantage of a larger RPM range, and sliders give you both better torque at low RPM, and higher top end. You say you hit 9000 RPMs? You should probably try some lighter slider weights, 9000 RPM is redlining, and that alone could explain your belt failures. If the changes you suggest would help, why doesn't the factory build them that way? I don't understand the advantage of sliders compared to rollers. Seems like sliders would be more likely to get stuck. Sliding causes more friction than rolling. In order to actually get a wider gear ratio range, you would have to use bigger pulleys that won't fit in the case. Yes, I rode the Vino 125 at near redline for almost 26,000 miles, and the engine held up just fine. The first two belts also held up fine. The third one shredded at 4,000 miles. I have no idea what the difference was. Besides the shredded belt (only one out of three) the other issue was climbing. IMO, when an engine hits or almost hits redline at full throttle on a flat level road with no wind, it is geared perfectly on the top end. The problem with a variator is that it is not geared low enough at the bottom end. Climbing a long step hill (about a 7% grade for 5 miles) it would bog badly, and the rpms would drop down to just over 4,000. Had it been to run around 8,500 rpms while climbing that hill, it would have had no problems. All that rpm would have provided the mechanical leverage to climb the hill without overstressing the engine. I used to have a Honda CT110, with the dual range transmission. It was easy to understand why Honda used that transmission. Even with that tiny little 110cc engine, that thing would have easily climbed Pike's Peak in low gear. My 2 speed 50cc Tomos moped easily climbed mountains that the Vino and Zuma wouldn't come close to climbing. Even 50cc made about 2 hp, and with a super low gear, easily carried the bike, me, and several pounds of stuff up that mountain, albeit a bit slowly. I just don't see any way to modify a CVT in any current scooter to have the kind of gear ratio range that a small manual transmission motorcycle would have. Even the Honda Cub has more pulling power than an average 125cc scooter. |
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Post by JerryScript on Dec 30, 2014 21:24:47 GMT -5
It's due to the shape of the sliders and the ramps on the inside of the variator which they work on. The sliders make contact at both ends of the ramp where rollers cannot due to their shape. This is what gives you greater use of both low and top end power. Rollers suffer from getting worn on a single side and not functioning properly as a result. You can do a quick google search, and I'm pretty sure you'll find most who have tried them prefer the sliders due to an increase in both low and top end response.
You are right, there is no way to modify a CVT to have the same power/response as a two speed tranny, it's just not going to happen. You can fine tune using a combo of weights and springs to get as close to what you want as you can, but you are not going to replicate a manual transmission's ability to downshift.
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Post by wilds on Dec 31, 2014 1:24:18 GMT -5
On one earlier CVT cover I drilled a couple of holes and that worked perfectly.  |
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Post by rockynv on Jan 1, 2015 9:07:07 GMT -5
When you ride a CVT at a fixed high speed constantly you wear a groove in the drive faces that will cause the belt to wear out prematurely.
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Post by frankauteri on Aug 8, 2017 21:07:28 GMT -5
If you have a CVT like the one on my 2009 Tomos Nitro 150 cc scooter, you will have a screen on the air intake (an rounded rectangle roughly 3x5 cm). The original screen was not only quickly clogged but broke very soon. I replaced it with a small piece of standard aluminum screen and hose clamp. Living and driving in and around a major US city in the North, I've found that the screen still gets covered quickly with debris, mostly leaf, lint, paper, and hair. We have to remember to clean these each and every season, or face the many consequences: poor acceleration / efficiency, CVT belt, clutch, and pulley wear are just a few of the most obvious.
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