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Roller, clutch springs and main clutch spring


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Posted

Hi, I have just purchased an Over thor 50cc 2 stroke scooter. The problem is the scooter was so underpowered so the dealer has put stronger clutch springs, 3.2 gram rollers(instead of the standard 4s). The main spring on a spring tester is a little less pressure than the standard one. The scooter now takes of ok but takes until 30kph until it shifts up into higher ratio. The engine is screaming until it shifts up. I would like it to shift up into higher gear a bit sooner to stop the engine revving like hell. What should I do?

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Posted

Heya, welcome to the forum.

Here's the deal, a 50cc only has so much power to work with.... Upgrading the CVT with performance springs and rollers may not be able to produce the results you are after.... 

Weight, riding conditions, etc etc are just some of the individual aspects of CVT tuning.... 

So here's what I recommend, first and foremost, look into upgrading to a 150cc.... There isn't a huge difference in the cost between a 50 and a 150....  If a 150 is not an option, I advise you to start looking into big bore kits and upgrading the air/fuel and exhaust....

Do you have access to tools and a shop/garage? 

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Posted

Thanks, Want to keep the 50cc as I don't have a licsence. My last scooters went better than this. I' just want it to shift up into higher ratio a little sooner. Do stronger clutch springs affect this?I would of thought the large (single big spring) would more have an effect here.Thanks for yor help

 

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Posted

 I' just want it to shift up into higher ratio a little sooner. Do stronger clutch springs affect this?

Short answer - Yes.

More detailed answer: The aftermarket clutch springs (main/contra and clutch pad) are rated at 1000, 1500 and 2000 rpm meaning at x rpm, they start to engage. However, just because your engine is at 2000 rpm, that doesn't mean that's what the clutch is spinning at... Remember, your variator opens and closes, the rate at which it does this is determined by your roller/slider weights.... As the belt climbs the variator, it drops into the clutch pulley and that's when your clutch starts making RPM's....

There's a fine tuning process with weights and springs and rider weight, conditions and other factor effect the end result. 

If you have had other 50cc scoots before and your current one is just slower, it could be from emissions controls and carb restrictions. Is your new scoot on a heavier type of frame? 

Some 50's and 150's share the same body style, goes without saying a 50cc has a hard time with the newer, heavier frame...

What is your scooter model? 

 

CVT_Belt_Travel.JPG

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Posted

What is the best way to start tuning a CVT? Like what order should you start.. contra. Clutch. Pillow if you have them. Then variator? 

And what is a 150cc stock contra or a way to find out?

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Posted

What is the best way to start tuning a CVT? Like what order should you start.. contra. Clutch. Pillow if you have them. Then variator? 

And what is a 150cc stock contra or a way to find out?

 my opinion

Contra, clutch, then the rollers

Contra- how long you want to go through the gears(ratio)

Clutch- rpm set point for the grabbing the bell

Rollers- heavy enough to push through the full clutch but not too early before the clutch grab

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Posted

 my opinion

Contra, clutch, then the rollers

Why in that order?

What I have discovered is that there is no order.... Each setup is unique and not always, is it recommended to upgrade all 3.....

My suggestion is this.... TUNE your CVT according to your needs.... Drive it - If your clutch is engaging to soon/late, adjust accordingly and same with your variator.... Keep in mind, gear ratio counts as a factor as well.

I would say i'm experienced when it comes to tuning the CVT, but I would by no means consider myself an expert.. I'm most curious as to why you suggest the order you do..

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Posted

Why in that order?

What I have discovered is that there is no order.... Each setup is unique and not always, is it recommended to upgrade all 3.....

My suggestion is this.... TUNE your CVT according to your needs.... Drive it - If your clutch is engaging to soon/late, adjust accordingly and same with your variator.... Keep in mind, gear ratio counts as a factor as well.

I would say i'm experienced when it comes to tuning the CVT, but I would by no means consider myself an expert.. I'm most curious as to why you suggest the order you do..

 

 it leaves the rollers last on the list to tune, i would say do all three since you only want to tune it once. But there are times where all three are not what you are looking for in the setup. I play safe having the longest ratio given with the shortest clutch grab I can get, so I have the red contra, blue clutch, and I do believe 12g rollers(can't remember they may be 10/12 mix)

And you are right there is no set order to do it but every time you change something you have to tune it. I like the set and forget, less time off the road. 

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