I ordered an SVI Duraclutch Friday of last week and received it Wednesday of this week.
Some background on my setup and issues with previous clutches. My Diesel is a 2011 and its original clutch was a unit similar to the 2009 and prior (I think) clutches. There is no center roller bearing and it's overall a simple reliable clutch with no engine braking. However, the 2011 with this clutch has some issues with hard shifting due to a number of factors. Basically since the diesel engine has a limited rpm range, Polaris had to do as much as they could with the range they had. Factory idle is approx. 1050 rpm and it governs out at around 3850 rpm. To make the most of this rpm range, Polaris tried to have the clutch engage as fast as possible and really cut back on clearances between the primary clutch sheaves and belt. This made some factory units have hard to impossible shifting due to clutch drag.
Polaris had a service bulletin for hard shifting and their fix for the 2011 clutch was a cheap (about $40), but effective, primary spring and secondary shim. The primary spring raised engagement rpm slightly and the secondary shim spread the secondary apart slightly. The clutch would now engage at around 1500 rpm instead of the previous 1250 rpm.
The 2012 and up Diesels use a version of the standard Polaris clutch with a roller center bearing. I bought a clutch like this and wasn't really satisfied it. Mostly I was unsatisfied because I didn't get the performance I expected and I paid for an entire 2012+ clutch. My engagement rpm was around 1250-1350 rpm but I still had some drag that produced hard shifting. I found that my clutches were slightly misaligned from the factory and shimmed it as close as I could get. This improved the drag issue but never did totally resolve it. At this point the drag was better than the original 2011 clutch but not quite as good as the modified 2011 clutch. My 2012 clutch had a particular issue where the clearances were so tight that when the belt was cold, shifting was perfect and all measurements with feeler gauges were well within spec. However, after getting the belt warm, it would expand slightly and those good clearances were no longer good, resulting in drag. Because of this and especially due to cost, I thought the modified 2011 clutch was the best bang for the buck.
Both the 2011 clutch and the 2012+ clutches do not have engine braking and have the same clutch feel as any other Polaris I've ridden. In this case I'm talking about the jerky engagement that comes from the pulley acting as both a clutch and a transmission. Easing into the throttle causes a jerky start due to the belt slipping and the best way I've read to overcome this was just to stab the throttle slightly to cause the pulley sheaves to come together and cut back on slippage.
Now to the good part.... as I'd mentioned earlier I received the Duraclutch this week. I was able to install it today and take it on a ride. I can honestly say, so far, that it has performed flawlessly and is everything is is promised to be. It is the absolute best modification I've made to my Ranger.
The best thing about the Duraclutch is that it separates the clutching action from the pulleys. It lets the pulleys act as a CVT and uses twin centrifugal clutches for clutching. The belt is constantly in tension and is constantly pinched by the pulleys. The centrifugal clutches are very smooth in engagement and since the belt is already pinched, starting the Ranger is much more smooth in all conditions. There is also no drag and no hard shifting with this clutch, even after riding hard and getting everything warmed up fully.
An additional bonus that I had never experienced was engine braking. I'm not able to compare it to the standard Polaris EBS since I've never owned one, I can say that the Duraclutch braking is very effective, even with a diesel. I would say a gas engine with the Duraclutch would perform much better in braking! The thought of an exhaust brake did cross my mind, but the valve springs are probably pretty light and I would be afraid of floating an exhaust valve during braking.
The Duraclutch uses a standard Polaris belt and fits under the regular CVT cover. The belt is not the same belt the stock Diesel clutches use, but is a common belt used on a much more powerful machine.
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