I know Fred has....anyone else? Thoughts on moving to a steeper angle helix? Or moving to a progressive helix?
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I was able to ride a dynamoe joe clutched 850 the other day and can say there was a noticeable difference between my stock sea level setup. It had a lot more bottom end power.
about blowing belts...
The only defense one has as far as a (my) clutch kit goes is being able to adjust the pivot weight so you get 7900~8000 rpms.
The lowest temperatures will be seen at 7900~8000 rpms. Regardless of hot, warm, incinerating temperatures – the lowest temperatures (Whatever they are) will be seen when you run at 7950 rpms.
.........Overrev or underrev raises temperatures.
Lower temperatures will be seen (whether its 200 or 400 deg)
-if you can lower engine speed at part throttle running.
-if you can get the engine to maintain its rated rpms at full throttle (7950ish) best it can be.
Clutch kits can't solve dynamic misalignment, engine mount gap and other elements making a cocktail of reasons adding up to the belt blowing - but at least a clutch kit can offer control of engine speeds.
Other than that, take the belt in to your dealer and tell BRP to fix this sh|t.
When the engine overrevs the engine torque goes lower. When the engine torque goes lower the upshift speed (opening) of the secondary clutch lowers. The belt does not go across the sheave face. The track speed you get is by virtue of high engine speed.
When the engine underrevs the engine torque lowers and following suit, the horsepower lowers. The belt does not shift across the clutch sheave face.
Both scenarios the belt stays in a localized area of the sheave faces and heat wont be efficiently drawn away from the belt.
When the belt can cross the pulley face, that is when the heat can be taken away the best.
Ok so you are in a 1 minute pull and have fairly stable track speed - the temperature elevates to an equilibrium point but the belt will have the lowest temperatures because of pulling at rated engine speed (whatever the temperatures are)
I'm still not following this completely, especially once you have stable track speed.
Belt slip = heat, I get that.
But over revving/under revving creating heat that somehow optimal RPM doesn't? I don't buy that.
Makes me think you maybe have not worked on clutching sleds very much if you believe that heat is not created from over or under revving...in practice it absolutely runs the coolest when the clutching is holding the engine at optimum rpm...that's a fact.
I do disagree with Joeys explanation as to why though. I tend to lean more towards the heat being created through slip. The belt will tend to slip when the motor pulls off peak output either over or under rev because the shift will stall. When the shift stalls the helix does not create adequate belt bite and you will get slip.
This can be masked somewhat when using large spring pressures but when you start clutching with lighter spring force, peak horsepower rpm or sometimes maybe 50 rpm under will always provide best performance and lowest heat. Keep her pulling and shifting. That keeps the belt hooked the clutch face with the force generated through the helix
I'm still not following this completely, especially once you have stable track speed.
Belt slip = heat, I get that.
But over revving/under revving creating heat that somehow optimal RPM doesn't? I don't buy that.
I'm still not following this completely, especially once you have stable track speed.
Belt slip = heat, I get that.
But over revving/under revving creating heat that somehow optimal RPM doesn't? I don't buy that.