Venom
Member
Hi,
I put a 51/43 helix on last weekend and now my RPMs have gone from 8500 to 9100. So I need to bring the RPMs down to 8400-8600.
I'm not thinking of replacing my weights, but replacing the outter rivets in my weights.
My stock rivets are steel, ...13.3mm (3.1 grams) outter, ...13.9mm (3.6 grams) inner.
The rivets I thought would be OK are 17.2mm (4.2 grams according to the local Yamaha dealership (I thought they were 4.5 grams)), but based on the calculations below, I'm thinking that 17.2mm are too heavy.
If the rule is 1 gram = 100RPM, then 1 gram per weight = 300RPM for 3 weights.
If I go with 17.2mm rivets I'm adding 3.3 grams (1.1 gram per weight), then the RPMs should come down 990 RPMs. So I'll still be hitting 8100RPM, which is too low.
If I go with 13.9mm rivets (as Turk suggested in a PM), then I'm adding 1.5 grams (0.5 grams per rivet), then the RPMs should come down 500 RPMs. So I'll still be hitting 8600, ...which is just right.
So I guess I should go for the 13.9mm (3.6 gram) rivet, correct?
This is all based on the rule that "1 gram = 100RPM", does this sound right?
Many thanks,
Roger.
I put a 51/43 helix on last weekend and now my RPMs have gone from 8500 to 9100. So I need to bring the RPMs down to 8400-8600.
I'm not thinking of replacing my weights, but replacing the outter rivets in my weights.
My stock rivets are steel, ...13.3mm (3.1 grams) outter, ...13.9mm (3.6 grams) inner.
The rivets I thought would be OK are 17.2mm (4.2 grams according to the local Yamaha dealership (I thought they were 4.5 grams)), but based on the calculations below, I'm thinking that 17.2mm are too heavy.
If the rule is 1 gram = 100RPM, then 1 gram per weight = 300RPM for 3 weights.
If I go with 17.2mm rivets I'm adding 3.3 grams (1.1 gram per weight), then the RPMs should come down 990 RPMs. So I'll still be hitting 8100RPM, which is too low.
If I go with 13.9mm rivets (as Turk suggested in a PM), then I'm adding 1.5 grams (0.5 grams per rivet), then the RPMs should come down 500 RPMs. So I'll still be hitting 8600, ...which is just right.
So I guess I should go for the 13.9mm (3.6 gram) rivet, correct?
This is all based on the rule that "1 gram = 100RPM", does this sound right?
Many thanks,
Roger.
Last edited:
Waterfoul
New member
I've seen it printed both ways here on TY... one gram = 100 rpm TOTAL, meaning the extra gram per weight is not added up but rather is considered the total and getting you only 100 rpm.
My own experience has shown that 1 gram per wieght does indeed = more or less 300 rpm... which means that you would add together the additonal grams PER flyweight.
Hope this helps
My own experience has shown that 1 gram per wieght does indeed = more or less 300 rpm... which means that you would add together the additonal grams PER flyweight.
Hope this helps