MPH - Lack of top end mph on XP Trail sled.
Question) What kind of results have you seen in testing with your kit for the XP 800r? I've read that a lot of these sleds are not pulling on top end? Does your kit improve or solve this issue or is it more of an improvement with back shift and shifting out completely?
Answer)I was 252 lbs when i built this kit and stock i could get 104mph repeatable, measuring with sportchek radar. After dialing in the clutch kit, it turned out to be about 107~108, using a bit of overdrive. I played with 27:45 right down to 22:45 and am back up to stock 27 because my sled runs well with it.
Part of the top end problem is the white letter 166 belt. Here is a few comments I have made about the belts causing poor top end.
Confirm that you have the correct belt width (measure) - The belt is supposed to be 1.44~1.5 inches wide. Some belts with 166 number and white writings are 1-3/8 wide, this will contribute to high system temperatures from fluctuating rpms and poor belt deflection and only .009” away from the wear limit (100 miles or less left to wear limit) A good replacement belt is 1.44~1.48 wide BRP#417300383 or BRP#417300377 (08 summit model)
Most other REV-XP, and REV-XR models, including the 1203 Four Strokes, will use a new belt, 417300383 which is the same length as the 166 but 1.5 mm wider. This belt would be a good choice for all previous years REVXP, because it is wider and would offer more adjustably. I highly recommend the 383 belt.
Put a wide belt (correct width belt) on the clutches and the sled will produce good top end.
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Answer) Some of the problem with the 07R lack of top end is the primary clutch sliding sheave, the button galley might be tapered so what happens as the shift increases, the levers push the sheave, pushing on the belt. As the sliding sheave button galley slides past the buttons, the fit gets tighter and tighter and will not allow good high mph. The galley is tapered and will not allow full shift.
I tested an 07R sled and found the galley was tapered, I could not get more than 70mph out of it. A stock clutch 600 144 would be about 10 mph faster top end on the road to get to the snow. I put the 07R primary clutch in an oven and heated to 160 degrees; It was difficult to move the sliding sheave towards full shift with no spring installed.
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