TT250 Variator info

[90GTVert]

Well, as you all know, I can't leave a scooter untouched, so here are a few things I found out about the CVT assembly:

I opened the CVT cover at around 300km to have a look. The belt was a Bando brand 828-22.5-30. I opened the variator and found the weights were not pristine like I would expect at this low mileage, but had several small flat spots in them.

I ordered a few different sizes of replacement sliding weights and some Kevlar belts to have on hand, and when they arrived, I opened it up again (500km) and notice that everything seems to have worn some, but nothing was bad except the rollers, which were getting noisey and filthy. The stock rollers are 26 grams, but since the RPM's have been in the mid to low 5,000 range, I installed 21 gram weights and a new belt. Instant difference in CVT noise (reduced) and the RPM's are now in the low 6's. Mid range power is improved as well. I hope to try out some more sizes as time allows. Stan

[Jacine]

Did you loose any top end?

[90GTVert]

Can't seem to notice any loss, but I wouldn't expect to either since the ratio remains the same, with the difference being when the weights reach full extension. I'm also still fooling with the 32mm carb so I'm doing the balancing act right now. I also want to try a set of 24's when they come in. Stan

jacine said:

Did you loose any top end?

[slowfire]

Master stan: have been watching your posts with intrest. your progess is important to all of us with the TT250 bikes. How often should we replace the variator weights/rollers and belts on our bikes. Where do we get them? And in general how do we get parts for our bikes? Many thanks slowfire

[90GTVert]

I'm not aware of any info on the belt or weight change intervals that could be deemed reliable, but the OEM weights were very rough from the start. Currently, replacement parts are going to be pretty tough for some items. On the positive side, the OEM belt is a better quality than on the 150's. Even though, when I replaced mine, I did notice that it had stretched some and was a lot more limber than the new Kevlar replacement. There is far less noise now, which could be attributed to either change, or both. MRP is doing some testing on a Daelim, but from what they have found so far, I'd say these are completely different beasts. Tank has not cooperated with them to do any aftermarket parts testing. Stan

slowfire said:

Stan: have been watching your posts with intrest. your progess is important to all of us with the TT250 bikes. How often should we replace the variator weights/rollers and belts on our bikes. Where do we get them? And in general how do we get parts for our bikes? Many thanks slowfire

[linda]

Hi, I recently purchased a roketa bali 250 touring and have been reading alot about roller weights and the Dr. pulley. This is my first but certainly not my last scoot and I want to make as many improvements as possible. Di i need to just buy the weights, if so what size? Or do I have to buy the whole variator kit.


Thanks,
Linda

[90GTVert]

The weights are all you need for a 250, BUT, you need to match them to the rider weight. As an example, on a CFMoto engine (250), they come with 23x18 26 gram weights. These are ok for a rider in the 160-175 weight range. If you are 200 pounds, I would drop 2 or 3 grams and so on for roughly each 25 pounds. If you weighed 125, I may either leave the 26 gram weights or even go up a couple grams.

Now if you weighed 200 pounds and you slapped in weights that are way too light, you will get jack rabbit take offs, and lose top speed. So, the formula is, SMALL CHANGES at a time to find the sweet spot for how you ride the scooter.

The idea here is to match the load to the engine power band, so it isn't exactly a one size fits all sort of thing. The best way to determine what is working best is to install a TinyTach or SenDEC tachometer so you can monitor what the engine is actually doing. You can find these on ebay for about $40 and they are very easy to install. Stan

linda said:

Hi, I recently purchased a roketa bali 250 touring and have been reading alot about roller weights and the Dr. pulley. This is my first but certainly not my last scoot and I want to make as many improvements as possible. Di i need to just buy the weights, if so what size? Or do I have to buy the whole variator kit.


Thanks,
Linda

[monty57]

Stan,

I have a RR 250 TLX with the CF-Moto engine and drive. I weigh in the 210 range but will be riding double from time to time with my wife. do you have any suggestion for a happy compromise and where do you order these weight kits?

[90GTVert]

23 or 24 grams should do it for you. Where to get them is a loaded question. I carry the sliding weights, but I don't like to promote parts sales on forums, so I'm sorry to mention it. Stan

monty57 said:

Stan,

I have a RR 250 TLX with the CF-Moto engine and drive. I weigh in the 210 range but will be riding double from time to time with my wife. do you have any suggestion for a happy compromise and where do you order these weight kits?

[MLN]

Quick question about the variator weights.

Twice there was mention of loosing top end (speed) while changing weights. I can only see this happening if the weights are too light and will not sling out far enough to completely close the variator. Am I correct in my thoughts?

Second question. What is the difference between roller weights and sliding weights? I've seen both mentioned.

Thanks

[linda]

Hi,

I'm buying my roller weights at the web site oregonvintage.com. They have alot of parts for the chinese bikes.
Stan thankyou so much for the info.


Linda

[linda]

I live in worcester MA, the roads are aweful, full of potholes, so alot of stop and go. Always lots of traffic. My top speed has only been 35mph. That might be it for me, but I want a jack rabbit take-off. With the oncoming traffic it's becoming more apparent that people in Worc. hate to slow down for scooter riders. I should probably go with the 24's. I'm 135lbs. (5'8") As far as that tach device I haven't a clue as to were it would go or how to test it. I'll try the 24's, if that doensn't work I'll go for the 28. No more overheating problems!!

Thanks,
Linda

[MLN]

mln said:

Quick question about the variator weights.

Twice there was mention of loosing top end (speed) while changing weights. I can only see this happening if the weights are too light and will not sling out far enough to completely close the variator. Am I correct in my thoughts?

Second question. What is the difference between roller weights and sliding weights? I've seen both mentioned.

Thanks

Stan, Dawg, Jim anyone?

[90GTVert]

Yes, if you go too light, the weights don't extend before the power curve is falling off. There is no set weight where this happens because the rider weight also plays a part in this.

The "roller" weights don't really roll, but they are round, so you naturally assume they do. The problem with them is that they develop random flat spots and they are generally made of cheaper materials. The sliding weights don't technically work differently, but because they are designed with large flat surfaces (sort of square in design) they don't flop from one wear spot to another, and the material is some tough stuff. My oppinion is that you feel the difference right away in a smoother transition through the various ratios. They are more expensive, but I believe this is one of the most cost effective and rewarding upgrades available (and cheaper than most other things you will do). This assumes you match the weights to your riding style and the load you haule.

The best method to get it perfect is to use a tachometer, but as a general guide for a 150cc scooter with a 200# rider, go to 12 grams and drop one gram for each 25-30 pounds of added rider weight. With a 250 use the 24 grams and drop 2-3 grams per 25-30 pounds of added rider weight. Stan

mln said:

mln said:

Quick question about the variator weights.

Twice there was mention of loosing top end (speed) while changing weights. I can only see this happening if the weights are too light and will not sling out far enough to completely close the variator. Am I correct in my thoughts?

Second question. What is the difference between roller weights and sliding weights? I've seen both mentioned.

Thanks

Stan, Dawg, Jim anyone?

[Andi]

ndnparts said:

Yes, if you go too light, the weights don't extend before the power curve is falling off. There is no set weight where this happens because the rider weight also plays a part in this.

The "roller" weights don't really roll, but they are round, so you naturally assume they do. The problem with them is that they develop random flat spots and they are generally made of cheaper materials. The sliding weights don't technically work differently, but because they are designed with large flat surfaces (sort of square in design) they don't flop from one wear spot to another, and the material is some tough stuff. My oppinion is that you feel the difference right away in a smoother transition through the various ratios. They are more expensive, but I believe this is one of the most cost effective and rewarding upgrades available (and cheaper than most other things you will do). This assumes you match the weights to your riding style and the load you haule.

The best method to get it perfect is to use a tachometer, but as a general guide for a 150cc scooter with a 200# rider, go to 12 grams and drop one gram for each 25-30 pounds of added rider weight. With a 250 use the 24 grams and drop 2-3 grams per 25-30 pounds of added rider weight. Stan

Even though I didn't post the question great info, that deserves some Karma and I think a sticky. Seems to me any scooter enthusiast will ask that question at some point in time.

What do you think a sticky in the tips and tricks section or better yet a "Technical Help Section" to permanently post all info like this? Could divide it up into different groupings, like "engine", "CVT", "electrical" etc. Unless I missed it somewhere and it's already there .

Andi

[MLN]

Thank you Stan! You've answered one question but created another for me. You stated that the rider weight also determines the proper roller/slider weights.

I can understand that in the area of acceleration as my 215 pounds would need more "gearing", lighter sliders, to accelerate me to top speed. What I don't follow is how rider weight plays any part of the sliders being flung out to the furthest position? I thought that would be a product of RPM. What am I missing here?

Thanks in advance!

[90GTVert]

The heavier weights are flung out to the limit before the engine can build RPM's which causes it to be lugging (at varying degrees). In normal cases, you never reach optimum RPM's because of the load is too great with a heavier rider than the weights were set up for. Unlike an automatic transmission, the CVT doesn't have sensors to adjust for load, so the weights are always trying to expand to a higher "gear", even when the engine isn't ready for that. This optimum RPM range for expansion will change with rider weight because of the load on the vehicle. The same thing happens when you change rear torque springs because all three elements (CVT weights, torque spring and rider weight) have to work together. My best guess is that the Chinese are using a calculation for a 150# rider as standard. Stan

mln said:

Thank you Stan! You've answered one question but created another for me. You stated that the rider weight also determines the proper roller/slider weights.

I can understand that in the area of acceleration as my 215 pounds would need more "gearing", lighter sliders, to accelerate me to top speed. What I don't follow is how rider weight plays any part of the sliders being flung out to the furthest position? I thought that would be a product of RPM. What am I missing here?

Thanks in advance!

[MLN]

Stan

Thanks for clearing that up. I wasn't as lost as I thought. The weights can get it to the highest gearing quick and the scoot may barely (if ever) reach top speed because the motor isn't building the power needed to to get there. Kind of like driving around in town with a car in 5th gear at 20 MPH. You can put the pedal to the floor but nothing really happens, not quickly anyway.

You've got me cleared up on the variator for now. Of course you know I always have another question. I'm not totally up to speed on the "torque spring" and it's function. I have a basic idea that it is meant to keep the "rear gear", if you will, from going to it's highest gearing too quickly. While the roller/sliders are pushing the belt on the front pulley out the belt has to get smaller on the rear pulley since the belt can't change sizes. The torque spring must be strong enough to keep the variator in check yet weak enough to allow the pulley to separate to achieve highest gearing at the appropriate time. I'm sure that there is more to it that I've over looked.

[Andi]

Stan,

I guess at 170 lbs for myself and 130 lbs of my wife (I got permission to post that), we wouldn't have to worry about changing roller weights riding one up.

If the roller weights are to heavy for the load carried by the scooter, I understand the sluggish acceleration, due to the weights extending all the way and therefore the gear ratio advancing before the engine gets proper RPM's.

Seems to me the roller weights provide sort of a timing, light rider - heavy roller weight to extend the weight quickly as to prevent over revving? And heavy rider - lighter roller weight to extend more slowly for the engine to catch up with the added load it has to move?

But why is it that if the weights are too light, besides great acceleration (and I guess possible over revving) is the top speed reduced, wouldn't the weights have to extend all the way in the end?

I guess when matching the roller weights to the rider weight, you would make sure that when cranking the throttle the engine is allowed to reach a certain RPM which matches the optimum torque? What is the optimum RPM? Is it different for the 150's and 250's?

Could a rider vary any of that by how the throttle is operated and therefore compensate for more or less rider weight? Basically saying instead of using lighter weights, to just turn the throttle gradually instead of cranking it all the way?

Andi

[MLN]

Andi

This is purely speculation on my part but I have a guess. I think if the weights are too light they will not be matched against the torque spring on the rear pulley. If the weights aren't heavy enough they won't be able to overcome the torque spring. If the rear pulley doesn't spread far enough to allow the highest gearing the belt can't climb up to the highest gearing on the front pulley. In essence you are stuck in 4th gear and can't shift to 6th.

[Andi]

MLN

That's a good point. I like your analysis about being stuck in 4th gear and can't shift to 6th.

Thats a good way to compare when using too heavy roller weights, it puts you in for example 6th gear when you are supposed to be in 4th.

I still wonder though if careful throttle increases instead of just cranking it one time from the get go would have an impact on the acceleration and performance.

Andi

[linda]

Hi everyone,

I recently purchased new weights for my roketa bali 250 at oregonvintage.com and am wondering about the proper torque setting to remove and tighten the variator nut. Should I buy an el cheapo air gun or impact wrench. I am not mechanically inclined and am trying to follow directions to get the most out of my new scooter. I'm a little nervous about replacing the weights myself, but I purchased the Haynes manual so hopefully the illustrations will guide me through to success.
Thanks Very Much
Linda

[90GTVert]

You can't really get a true torque reading on the nut since the shaft will want to spin, but yes, an air impact is the way to go for removing the nut. You'll be surprised at how easy it is to replace the weights once you open it up. If you think you are in trouble just send me a private email and I'll walk through it with you, but I doubt you'll need it. Stan

linda said:

Hi everyone,

I recently purchased new weights for my roketa bali 250 at oregonvintage.com and am wondering about the proper torque setting to remove and tighten the variator nut. Should I buy an el cheapo air gun or impact wrench. I am not mechanically inclined and am trying to follow directions to get the most out of my new scooter. I'm a little nervous about replacing the weights myself, but I purchased the Haynes manual so hopefully the illustrations will guide me through to success.
Thanks Very Much
Linda

[linda]

Hi everyone,
I just want to repeat what happened to me, and to new scooterist if they change there belts or weights. Make sure you put the fan over the splines when reapplying . I did not notice and thought I put the fan on as far as it would go, then screwed the nut with an impact wrench. Put the CVT cover on, and the blades ripped into into the cvt cover, spurring out the splines on the crankshaft. Now I cannot get the variator off or on without a slight nudge from a rubber mallet. So, basically the scoot is crapped. One small mistake. Maxing out my credit card I just purchased the new roketa bali/WM. $2014.00 from countyimports.com. At least I won't have to purchase parts for quite awhile.