Clutch weight vs RPMS Apex

[02ViperMody44]

Just need a question answered, as I am looking to raise the max rpms on my Apex. What is the general rule on weight vs rpms? Is 1 gram equal to apprx. 150 to 200 rpms? And is that 1 gram per individual clutch weight only or is that 1 gram total on the clutch, after adding or subtracting weight, for each clutch arm on the clutch?
Thanks

 

[Fast]

Just need a question answered, as I am looking to raise the max rpms on my Apex. What is the general rule on weight vs rpms? Is 1 gram equal to apprx. 150 to 200 rpms? And is that 1 gram per individual clutch weight only or is that 1 gram total on the clutch, after adding or subtracting weight, for each clutch arm on the clutch?
Thanks

What rpm is it at now is it all stock clutching it needs to see 10400 rpm max

 

[Fast]

What rpm is it at now is it all stock clutching it needs to see 10400 rpm max

Easy way to raise the rpm is add a washer behind the primary spring for 200rpm for a max of 3 washers and 600rpm

 

[steiner]

1 gram per weight

 

[02ViperMody44]

1 gram per weight

Thank you Steiner! Is that the rule of thumb, appx 200 rpms per gram?

 

[steiner]

The rule a thumb was 1 gram per weight for 100rpm change on non boosted sleds.

 

[stevewithOCD]

There are 3 rivets on my stock '07 Apex weight.
I ground off 1 gram from the tip rivet & gained just under 100 rpm's on top.

 

[stevewithOCD]

You can also buy different weight rivets.

 

[02ViperMody44]

Thanks for the replies. I did a gear swap, and ahead of that I had some clutch work done, to accommodate the ratio change, but I believe they over weighted them as my rpms are down and just want to handle the clutch weight change myself to minimize down time.

 

[steiner]

What type of weights are you running? Stock or Aftermarket?? If aftermarket it is usually easy to tune in the rpm with the washers. I do it without removing the clutch by removing the primary cover and spring. This takes the pressure off the weights and allows access to the washers.

 

[Stubbs]

Different profiles of primary weights are more/less sensitive to tip weight than others. Aggressive curvatures (Supertips, Heavy Hitters) tend to follow the 1 gram = 150/200 rpm ish rule. The flat/heavy stock weights seem to be less affected, requiring more like 2 grams for a comparable change in RPM. Keep in mind conditions can play a huge factor in the peak RPM you see day to day.

 

[02ViperMody44]

Yes, stock weights. And was on some decent hard pack. Just figured I would do my own weight change, and wanted some advice before tackling it.

 

[Stubbs]

How many miles on the sled so far this season? It’s not uncommon for the valve seats in the cylinder head to rust a little over the summer, and not seal properly for the first couple of rides until it’s worn off. This can cause low RPM for the first couple of trips out. A mix of old and new fuel may also contribute to early season low RPM.

 

[02ViperMody44]

How many miles on the sled so far this season? It’s not uncommon for the valve seats in the cylinder head to rust a little over the summer, and not seal properly for the first couple of rides until it’s worn off. This can cause low RPM for the first couple of trips out. A mix of old and new fuel may also contribute to early season low RPM.

I had weight added to my clutches ahead of a gear change, and he didn't realize I had an Airbox, PCV, shorter air horns and set my target rpms down from where I wanted it. Just going to do it myself.