850 clutching
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Polaris turbo section, TRS clutching part 1-4. Read it and see if you can get on board with the concept?
Tony: sorry to hear about your back. Mine is starting scare me.. and I'm just pushing 45.
Get better!
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I've seen the same grooving from the 8dn belt from Yamaha on the triples. That belt was also hard as a rock. Went through several clutch sheaves on a 1180 union bay. One actually flew through the hood at 9000 rpm. It was hard to get a bite on the belt also. The gates belt was softer but could not hold the power either of that motor.
Is that track speed with a 155 2.6 or a 163 3”, I’m only pulling 40 mph with my 163 3” but I’m trying to figure out a setup on a team tied secondary
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Reddragon800
Well-known member
Red800. Have you taken into consideration speedo inaccuracy with the Pro gears?
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Reddragon800
Well-known member
Yes, the stock gears are 22/43 = 1.95
Pro Gears are 21/44 = 2.10
This a 7% gear down. The gauge would read 50-51 mph. But that wasn't the actual track speed. Its was closer to 47-48 mph.
Its about 3.5 mph difference from what the gauge says
2.10 ratio w/7 tooth at 1-1 is about 77mph/123kmh.
At 40-50mph the belt is riding on a little more than half way up on the primary sheave. This is about a 2-1 ratio.
1-1 is most efficient according to Olav Aaen. Why not get the clutches to run at 1-1?
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Never said I was running the old Axys belt. And no you don’t need a steep multi angle helix to get good bottom end.
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Reddragon800
Well-known member
Who said it was steep?
"Relatively steep" It's clear your helix is steeper than a 42-32f
TRS clutching shifts out more than any clutching that I know of.
TRS and Indy Specialty (very similar) clutching are very well regarded for performance and increasing belt life. It is well documented on here and hundreds, if not thousands of people run it with success.
There's more than one way to skin the cat though; I'm sure your method works as well.
Can you please elaborate on why you believe this is happening?
Yes.
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Reddragon800
Well-known member
One thing i forgot to ask was what elevation is the 66 gram weights for? I have been testing in 6-8000 feet.
In theory, less primary weight will have less pull or squeeze on the belt. I do understand that the softer secondary spring will make up for that difference. However, leaving the stiffer primary spring will again offset that difference. Again, in theory it will hit a limit to how much it can shift due to the lighter weights and stiff primary spring. I would think that it would be more efficient to go to a 120-310 or 120-300 to allow the lighter weights to have adequate pull at full RPM.
In theory, less primary weight will have less pull or squeeze on the belt. I do understand that the softer secondary spring will make up for that difference. However, leaving the stiffer primary spring will again offset that difference. Again, in theory it will hit a limit to how much it can shift due to the lighter weights and stiff primary spring. I would think that it would be more efficient to go to a 120-310 or 120-300 to allow the lighter weights to have adequate pull at full RPM.
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Reddragon800
Well-known member
OK, fair enough. I couldn't find any info on the TRS weights. I assumed they were the same as 10 series weight.
If my memory serves me correctly in order to run in 1:1(full shift) hillclimbing your sled would have to be geared for a top speed of roughly 45 MPH. I can't find my clutching efficiency breakdown but I believe the difference in efficiency between 2:1 and 1:1 was negligible like 1 or 2%.
