|
|
Post by moore716 on Oct 7, 2011 5:23:30 GMT -5
I may be missing this but is there a sticky anywhere that is like a CVT tuning for dummies. Something that tells exactly what to expect by changing the rollers, torque and clutch springs either heavier or softer. Also how different combinations would perform together. It would be cool to just have a chart to use as a baseline. I realize rider weight, climate, motor size, and road conditions all affect this as well.
|
|
|
|
Post by 90GTVert on Oct 7, 2011 8:26:41 GMT -5
Very basic : The weights in the variator and the spring in the rear pulley counteract each other. The simplest way to get in tune there is to select a contra spring that does not cause any belt slip. You would notice black lines on your pulleys, made up of belt material, if you were getting belt slip. If you experience slip, go with a stiffer contra. When you move up to a stiffer contra spring, your RPM will increase unless you also increase roller weight. The goal is to tune the CVT to keep RPM in the range where you make the most power. It varies a bit by preference. Sometimes I find that tuning for max performance is a little too rev happy for what I like riding around on public roads so I tone it down a bit. If the weights are too heavy it will be sluggish. If the weights are too light it will respond very quickly and rev high, but can lose a little or a lot of top speed depending just how light they are. Lighter Rollers/Sliders = Higher RPM Heavier Rollers/Sliders = Lower RPM Stiffer Contra/Torque/Main Spring = Higher RPM Softer Contra/Torque/Main Spring = Lower RPM Stiffer Clutch Shoe Springs = Higher RPM/Later Clutch Engagement Softer Clutch Shoe Springs = Lower RPM/Earlier Clutch Engagment Clutch springs control initial engagement of the clutch and have the greatest effect on initial launch. Most 50-70cc setups, especially with a pipe or porting, get best results with stiffer, 2000RPM, springs. When looking at clutch and contra springs from the Chinese and Taiwanese manufacturers, you will find a common theme for color coding springs : Blue = 1000 RPM
Yellow = 1500 RPM
Red = 2000 RPMFor clutch springs, that means the clutch will engage roughly that RPM above what it is now. For the contra it's supposed to be saying acceleration RPM will increase roughly that much above what it is now. I started writing something some time ago and never finished it. I kept getting frustrated trying to explain things in detail so they made any sense "on paper". Here is a link that you might find useful... atv.off-road.com/atv/tech/cvt-clutch-tuning-basics-part-1-background-and-basics-18812.html |
|
|
|
Post by moore716 on Oct 9, 2011 20:19:34 GMT -5
this is very helpful thanks for the info. right now i have 5g rollers and 2k clutch and torque springs top end is good. mid to top is OK. bottom to mid is slow and bottom end is non existent. I wish it would grab more. I would love to ride wheelies with this thing but I'm afraid I will lose all top end then and I am putting some miles on this thing. I just get tired of having to push it everytime I stop to get it rolling.
|
|
|
|
Post by 90GTVert on Oct 9, 2011 20:28:26 GMT -5
It sounds like you need to try and get your belt closer to the center of the front pulley/closer to the outside edge of the rear pulley when at rest. This will give you a better gearing for take off. There is info about shimming and modding the variator in the tech library that can help you accomplish this.
|
|
|
|
Post by moore716 on Oct 9, 2011 20:31:21 GMT -5
thank you kind sir;)
|
|
|
|
Post by moore716 on Oct 9, 2011 20:43:15 GMT -5
good info. I will have to see if I can chuck these pulleys up in my lathe at home or the one at work. If not I can mount them face up on my mill and go to town that way  ! |
|
!