TRA settups...attn clutch guru's

[NoSecondChances]

I've always felt the TRA primary was a descent clutch and easy to tune once you understood how to blend the ramp profile, weight of the arm assembly and spring. The issue in the mountains above 9000' was the secondary and getting the torque senseing secondary to work in harmony with the primary above 6000 rpm.....My answer to that even with the best setup i can throw at the clutch was to be a better manager of the throttle knowing full well that if i backed off the throttle the arm/roller/pinweight assembly would fall off the power curve of the ramp and would than have to recover the LOST RPM and TRACK SPEED....

OT

One of the best responses on this thread yet IMO!! My feelings are very much the same, and I like the TRA for all the reasons you can add weight on the arms, pins, rollers, etc to change the characteristics to the shifting pattern and rpms, not to mention the springs, ramps, ability to change ramp angle by the simple turn of a clicker. One of the things that I have found is that there is almost too much adjustability with this clutch, and it starts to overwhelm some people. As OT said, when you are down on power at elevation (unless you have BOOST!! ) there is no other cure than to change your riding style to maintain the rpms OR change the clutching setup to compensate (like any of us want to take time out of our riding day to change setups for ____ ft and above and then change back when dropping down below _____ ft).

That being said, I'ma big fan of using just enough weight to grip the belt properly and using a lower engagement as I find it increases the overall useable RPM band and the lower RPMs, the lower the clutch temps (higher rpms, less efficiency). The motor tends to respond to throttle fluctations better (lighter flywheel effect) and this works for the tight technical type of riding I do. If I was to be more of a long hill puller where I wanted to maintain RPMs, I would be using a setup more like WinterBrew has found (heavier flywheel effect) to stabilize RPMs and hold them a little better, but I found that for my riding style I prefer a faster revving clutch with lower engagement, even if I have to sacrifice some motor/clutch ability to sustain rpms on a longer pull. Find a setup that makes your sled work well in all conditions and ride!

 

[YamaDoo PolCat]

I'ma big fan of using just enough weight to grip the belt properly and using a lower engagement as I find it increases the overall useable RPM band and the lower RPMs, the lower the clutch temps (higher rpms, less efficiency). The motor tends to respond to throttle fluctations better (lighter flywheel effect) and this works for the tight technical type of riding I do. If I was to be more of a long hill puller where I wanted to maintain RPMs, I would be using a setup more like WinterBrew has found (heavier flywheel effect) to stabilize RPMs and hold them a little better, but I found that for my riding style I prefer a faster revving clutch with lower engagement, even if I have to sacrifice some motor/clutch ability to sustain rpms on a longer pull. Find a setup that makes your sled work well in all conditions and ride!

Never ran into anyone that would tune like that. Curious, what doo you ride and what kind of terrain? Obviously don't need much power, so couldn't you just use a chainsaw clutch and hook that up to the jackshaft? How doo you know you have just enough weight to grip the belt properly, vs improperly?

 

[winter brew]

"How doo you know you have just enough weight to grip the belt properly, vs improperly?"

I know! I know!! (raising hand in class)

Temperature???

 

[Maxwe]

Pol that route looks a little sketchy you got going across that mountain face. Dont look down.

 

[fatguy1]

Pol that route looks a little sketchy you got going across that mountain face. Dont look down.

I've been there, but never did it cross my mind to go across there... Crazy

 

[Teth-Air]

Okay guys, I road yesterday and after reading this post I was watching my rpms and speed as close as posssible and played with the clickers. I found that on a steep climb in clicker 3, my 08 XP would pull 8200 rpm (approx) and about 80 kph. I was not too impressed as it felt slow. When I clicked to #2, the machine pulled way harder and accellerated faster and hit 85 kph but only hit 8077 rpm.

My questions are:

Is the secondary slipping at 8200 rpm due to hitting peak hp and I'm loosing track speed because of it?

and

Would the yellow secondary spring cure this?

conditions,

only punched the trottle fully 1/2 way up climb, soft heavy snow with about 3inches loose ontop of base

SLP head, Blue/Purple primary spring, MBRP can, 12+6+6 mm set screws in pins. 154 tack with 19 tooth gear at present

Any ideas are appreciated

 

[winter brew]

Teth-air....in that scenario, when you clicked down you added more pinch to the belt on the primary and it balanced better with the pinch of the secondary. If you went with more secondary spring and changed nothing else it would likely act as it did before you clicked down, with the secondary overpowering the primary resulting in more RPM, not loading the engine, less track speed and more heat. The key is finding the balance between primary and secondary. You never know what will work best without experimenting.

 

[tollen77]

Teth-air....in that scenario, when you clicked down you added more pinch to the belt on the primary and it balanced better with the pinch of the secondary. If you went with more secondary spring and changed nothing else it would likely act as it did before you clicked down, with the secondary overpowering the primary resulting in more RPM, not loading the engine, less track speed and more heat. The key is finding the balance between primary and secondary. You never know what will work best without experimenting.

Couldn't agree more! You most likely had equalized the pressures provided by both clutches. To get back up to RPM you might try removing a little weight (say 0.5 gram) and try then.

The other thing to keep in mind is that, although this was better, that doesn't mean that you've arrived at the best. The only way to really be sure that the clutch pressures are equalized is to verify that neither clutch is appreciably hotter than the other.


.

 

[NoSecondChances]

Never ran into anyone that would tune like that. Curious, what doo you ride and what kind of terrain? Obviously don't need much power, so couldn't you just use a chainsaw clutch and hook that up to the jackshaft? How doo you know you have just enough weight to grip the belt properly, vs improperly?

Read WB's post below yours. I can touch my clutches after a long pull, hot but still touchable. This means belt is not slipping. I think that I am a little short on the gears at times which helps, but I like to ride technical lines, on and off the throttle, turns and tight trees and chutes. Need a sled that can rev a little faster to try and regain the RPMs after a quick little turn or jump, don't need to swing a laggy clutch. The clutch is just another flywheel on your sled as well, the more weight your crank has to spin, the longer it will take to get the revs up. Once you get them there its all good, but if the places I like to ride, need to be on and the throttle a bunch. Sorry, you couldn't be more wrong about needing power to ride where I try, not running a chainsaw but I do have enough power in both mod sleds IMO.

 

[Original Tetonice]

Okay guys, I road yesterday and after reading this post I was watching my rpms and speed as close as posssible and played with the clickers. I found that on a steep climb in clicker 3, my 08 XP would pull 8200 rpm (approx) and about 80 kph. I was not too impressed as it felt slow. When I clicked to #2, the machine pulled way harder and accellerated faster and hit 85 kph but only hit 8077 rpm.

My questions are:

Is the secondary slipping at 8200 rpm due to hitting peak hp and I'm loosing track speed because of it?

and

Would the yellow secondary spring cure this?

conditions,

only punched the trottle fully 1/2 way up climb, soft heavy snow with about 3inches loose ontop of base

SLP head, Blue/Purple primary spring, MBRP can, 12+6+6 mm set screws in pins. 154 tack with 19 tooth gear at present

Any ideas are appreciated

At 8200 rpm your out of the powerband and your HP power will drop off like a rock. The 800R motor and they all slightly differ likes to peak between 8000 & 8150. When you clicked down from #3 to #2 you effectively drop 100rpm plus or minus which is just what your clickers should do. 8200rpm minus 100rpm = 8100 rpm which is "perfect peak power" and why your sled hooked up alot better once you clicked down from #3 to #2.

OT

 

[Original Tetonice]

You guys should also know that when you go from clicker #3 to #2 you have just decreased the force of the roller on the ramp as well as decreased your rpm 100rpm for every click down. You have also decreased the sqweeze on the belt which isn't a bad thing and can result in consistant clutch performance.

OT

 

[Teth-Air]

Thanks for your help guys. I have a yellow secondary spring so without changing anything else, I will test it out next weekend. I also expect that this will be just like clicking up but I'm hoping for a plesant surprize.

I will let you know after the test.

 

[Cinno]

Okay guys, I road yesterday and after reading this post I was watching my rpms and speed as close as posssible and played with the clickers. I found that on a steep climb in clicker 3, my 08 XP would pull 8200 rpm (approx) and about 80 kph. I was not too impressed as it felt slow. When I clicked to #2, the machine pulled way harder and accellerated faster and hit 85 kph but only hit 8077 rpm.

My questions are:

Is the secondary slipping at 8200 rpm due to hitting peak hp and I'm loosing track speed because of it?

and

Would the yellow secondary spring cure this?

conditions,

only punched the trottle fully 1/2 way up climb, soft heavy snow with about 3inches loose ontop of base

SLP head, Blue/Purple primary spring, MBRP can, 12+6+6 mm set screws in pins. 154 tack with 19 tooth gear at present

Any ideas are appreciated

The 09' Skidoo race manual says the published max horsepower rpm is not necessarily the rpm you calibrate to as it is a dyno measured rpm determined under lab enviroment. It says to change clicker and observe acceleration. It also says lowering the clicker may change the rpm little but yield higher acceleration. Looks like you proved the manual correct.

Cinno

 

[Teth-Air]

The 09' Skidoo race manual says the published max horsepower rpm is not necessarily the rpm you calibrate to as it is a dyno measured rpm determined under lab enviroment. It says to change clicker and observe acceleration. It also says lowering the clicker may change the rpm little but yield higher acceleration. Looks like you proved the manual correct.

Cinno

Cinno, I was thinking this and was wondering if the SLP head has increased the torque lower down and this may be why I am seeing more gains at the lower rpm?

 

[tollen77]

You guys should also know that when you go from clicker #3 to #2 you have just decreased the force of the roller on the ramp as well as decreased your rpm 100rpm for every click down. You have also decreased the sqweeze on the belt which isn't a bad thing and can result in consistant clutch performance.

OT

You mean when you go up in clickers, right OT??? The lower the clicker the flatter the angle of the ramp. Flatter ramps = increased clamping force. The decreased RPM you see is a direct result of the increased load on the engine.

 

[banditpowdercoat]

Ya what Tollen said. I allways thought Lowering clicker loads engine more because flatter ramp profile, the rollers have less of a "hill" to climb, so the move out more, thus pushing sheave closed a little more"pinch"

 

[winter brew]

You mean when you go up in clickers, right OT??? The lower the clicker the flatter the angle of the ramp. Flatter ramps = increased clamping force. The decreased RPM you see is a direct result of the increased load on the engine.

This is correct.

 

[Original Tetonice]

Ya what Tollen said. I allways thought Lowering clicker loads engine more because flatter ramp profile, the rollers have less of a "hill" to climb, so the move out more, thus pushing sheave closed a little more"pinch"

Lets 1st of all understand how your clickers function. From clicker setting #1 to #5 for each click you increase 100rpm at high altitudes lower elevations might see as high as 200 rpm...For each click of the clicker UP 2 to 5 you have effectively moved the ramp(s) which inturn put more force on the roller/arm assembly and slighty slows the shift character which inturn because of the added force/load between the ramp profile/roller increases rpm.....When you click down from #5 to #1 you have effectively decreased the force on the ramp/roller which shows on the rpm by a 100rpm decrease in rpm for each click down #5 to #1. Confused ????..Thats what to much DooTalk will do to you. LOL....And than we have the secondary and since it's toque sensing how it factors into the picture

May The FORCE Be With You

Simplest thing alot of you need to do is buy a skidoo race manuel part # 484200084 it explains the function(s) pretty clearly.

Skidoo motors run there best when there "under load" with weight and force from the TRA. Take the weigh and the force of the TRA away and the results is in consistant rpm and slow track speed.

OT

 

[Original Tetonice]

Some of you guys need to understand how it's a combinaton of the weight and centrifigul force that pinches the belt in the primary as well....The forums spend alot of time talking about pinweight 10g, 12g, 14g, when the bigger picture might come as a surprise to som....The 3 TRA ramps, & TRA 3 arm/roller assembly (no pinweight added) weigh over 300g's +/-.....Bottom Line folks it takes weight and force to sqweeze the belt for high altitude deep snow riding.

OT

 

[banditpowdercoat]

Gotta bring Dootalk in Huh??? does iot matter where people frequent?? Not to my clutch it doesnt.

Ohh, and I DOO have the race manual

And when you clicker down, your lessening the ramp angle. So less angle, the easier it is for the roller to move UP this angle. The more the roller moves away from the clutch centerline, the more centri***al force it has, correct?? More force, Pushes even harder on the ramp.

All in all, clicking DOWN, the clutch tries to make the belt ride Higher in the primary, given same RPM/Load conditions


Thats the way I see it