Due to me having to talk about or type in a e-mail or forum what shift speed is, I thought I would just write a tech article to point to on it.
Shift speed is basically the engine RPM the engine runs at all the time under load due to the properties of the CVT clutch system. When we are tuning a clutch this RPM is the main focus of the tuning.
Assuming you have a clutch set up that is in the ball park to begin with then fine tuning shift speed is where it is. Also we use it to determine if you have a big issue with what you have now stock or modified.
To get shift speed, get on flat ground in high range and floor it, watch tach and the RPM where the engine just starts to level out is shift speed. The wide open RPM is not it and wide open RPM can NOT be controlled by clutching unless it is way off like a super stiff secondary spring that will not let the primary open. On a dyno and graphing RPM, you will see RPM ramp up quickly, go flat then ramp up again when the belt is fully shifted out. The flat part of the graph is the shift speed.
Typically with a 800 polaris, we shoot for 6200 RPM at shift speed and on a 900 XP we shoot for 8200 RPM. Modified engines with cam changes etc will operate at a higher RPM but for the most part and most people these two RPM's is what we are shooting for.
If you ride in the dunes alot or sand, or mud or wherever and you know your clutching is off there, then you need to get shift speed where you ride at so you can tune your clutch for that.
Keep in mind, a clutch tune for sand tires in the sand is going to different than when you get back home and put your stock tires back on. Each tire set will require a different set up which makes the Dalton adjustable clutch kit so desirable, just too easy to change and can be done right on the vehicle.
With a clutch kit assuming you have all matching parts from one company like Dalton, you simply change the weight of the flyweights to affect shift speed. Say you are running 5900 rpm on a 800 and 7900 on a 900 then take one set screw out of the weights to lighten them up to raise the RPM.
On my own vehicle I went to 26x9x12 rear tires and my shift speed went to 8450 to 8500 which is the rev limiter so I had install a Dalton kit and use the set up for small tires which was heavier flyweights which brought my RPM back down to 8200 where I wanted it. Then I could hit shift speed like I was supposed to, no premature rev limiter hitting and my top speed went back up.
One more thing, a clutch kit should never hurt top speed if it does then it is off, way off. Switch brands or adjust it if it is a adjstable kit.
Hope this cleared up what shift speed is.
Todd
Shift speed is basically the engine RPM the engine runs at all the time under load due to the properties of the CVT clutch system. When we are tuning a clutch this RPM is the main focus of the tuning.
Assuming you have a clutch set up that is in the ball park to begin with then fine tuning shift speed is where it is. Also we use it to determine if you have a big issue with what you have now stock or modified.
To get shift speed, get on flat ground in high range and floor it, watch tach and the RPM where the engine just starts to level out is shift speed. The wide open RPM is not it and wide open RPM can NOT be controlled by clutching unless it is way off like a super stiff secondary spring that will not let the primary open. On a dyno and graphing RPM, you will see RPM ramp up quickly, go flat then ramp up again when the belt is fully shifted out. The flat part of the graph is the shift speed.
Typically with a 800 polaris, we shoot for 6200 RPM at shift speed and on a 900 XP we shoot for 8200 RPM. Modified engines with cam changes etc will operate at a higher RPM but for the most part and most people these two RPM's is what we are shooting for.
If you ride in the dunes alot or sand, or mud or wherever and you know your clutching is off there, then you need to get shift speed where you ride at so you can tune your clutch for that.
Keep in mind, a clutch tune for sand tires in the sand is going to different than when you get back home and put your stock tires back on. Each tire set will require a different set up which makes the Dalton adjustable clutch kit so desirable, just too easy to change and can be done right on the vehicle.
With a clutch kit assuming you have all matching parts from one company like Dalton, you simply change the weight of the flyweights to affect shift speed. Say you are running 5900 rpm on a 800 and 7900 on a 900 then take one set screw out of the weights to lighten them up to raise the RPM.
On my own vehicle I went to 26x9x12 rear tires and my shift speed went to 8450 to 8500 which is the rev limiter so I had install a Dalton kit and use the set up for small tires which was heavier flyweights which brought my RPM back down to 8200 where I wanted it. Then I could hit shift speed like I was supposed to, no premature rev limiter hitting and my top speed went back up.
One more thing, a clutch kit should never hurt top speed if it does then it is off, way off. Switch brands or adjust it if it is a adjstable kit.
Hope this cleared up what shift speed is.
Todd
