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Nytro XTX: Problem Weight Placement on Supertips

rock doc

VIP Member
Joined
Mar 3, 2008
Messages
247
Location
Saint John, NB Canada
Country
Canada
Snowmobile
2018 Sidewinder XTX SE. Previous 2011 Nytro xtx, 2016 Apex GT, 1998 Polaris Indy 600 xlt
I recently bought a primary clutch from Yamaha Parts Express for my Nytro XTX with a studded 1.25" track. Everything else on the sled is stock. the trails around here are below 1000'. I weight 170Ibs

The primary came with the OPO spring and 1 washer in the tip. It overreved badly. Went to 2 washers tip: 1M: 1 heel and put a new softer Carilse Ultramax belt on. Big improvement but still over revved. Current setup 2 tip/1Middle/3 Heel. Still overrevving but seems to be close.

Unfortunately I am out of weight and only have 9 screws.
  1. Do the weights needs to be distributed evenly on both sides of the cam? Right now I have all the weight placed on the left side. Could this be causing the weight to bind?
  2. Any thoughts on how I can get this clutch to work with the weight I have? I am considering placing 4 washers on the heel (2 on each side of the cam) and leaving 2 washers on the left side of the tip.

Any advice would be appreciated. It does not make sense that this clutch was so far off - apparently Ulmer was the one who gave the initial input on how to set the clutch up. I doubt he would be off this much on a stock setup. The secondary is shifting ok so the problem is in the primary. I have spun this sled on the stand and it seems the clutches are moving freely.
 

Ulmer Racing doesn't have a clutch kit for the FX Nytro that changes just the primary spring and weights. The Ulmer Racing clutch kit comes with primary spring, weights, and helix. Are you trying to run the stock secondary setup? That will require a completely different setup. Also if your weights only had 1 thin washer out on the tip, someone has messed with them, as that is not how Ulmer Racing has anyone setup.

For stock secondary setup try this, Ulmer Racing has not tested with stock secondary, so this is a shooting from the hip setup.

Heel: Thick tungsten insert on 1 side, 2 - thin washers on the other
Mid: 1 thin washer only on 1 side
Tip: 1 thin washer only on 1 side
 
Thanks very much!!! I figured something was off. Seems most are running a lot of heel weight with good results.

I am not sure if the helix is different. It came assembled with some spare washers. I will take it apart and compare to my stock clutch sometime next week. Would the profile and mass of the cams be stamped on them somewhere? I looked and did not notice any when I had it apart last week.
 
Cam arms will be stamped with a 50Y on them usually. If you have a gram scale they will be 51 or so grams with no washers installed on them.
 
I finally got a chance to try this setup.

Heel: Thick tungsten insert on 1 side, 2 - thin washers on the other
Mid: 1 thin washer only on 1 side
Tip: 1 thin washer only on 1 side


Seemed to work pretty good. It seems a little lazy in the mid range, taking tine to build rps. I was peaking out at 8500 rpm at close to 100mph (on the speedo) in icy conditions. I think I need to remove 1 gram/ washer. Where would you recommend removing weight. I was thinking about leaving the mid mount empty. How would this impact the backshift?
 


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