Lets have a discussion about clutching and how changing components affects clutching. Please add to the topic with how you’d attack this or any other clutching situation
Basic clutch principles
Clutch fly weights: The Heavier the weight the lower shift RPM The lighter the higher shift RPM. Weight profile also dictates this as well as Roller.
Primary springs: the Heavier preload a Primary spring has the high the engagement. As you lower the preload you will lower the engagement
Primary springs: The heavier the total force on a primary spring the higher your full shift RPM will be. As you decrease the total force on a spring the lower the full shift rpm.
Secondary springs: Secondary springs are a tough one. Yamaha Secondary springs are rated by torsion twist. The Polaris silver blue is rated with side pressure. You don't put a tone of twist to it to make it affective. With Yamaha springs, if you want a ton of back shift you increase the twist. If you want more up shift you decrease the twist.
Helix angles:The steeper the angle, the faster the shift, the shallower the angle the slower the shift.
Subject
Drag Racing
I like to run as heavy a weight as possible and engage as high as I can with out blowing the track out. By doing this you have to watch the helix you use because you will pull the motor down with a super steep helix. Generally I've found drag racers like to use a steep initial angle helix with a shallow finish angle. The reason you do this is the steep angle increases the up shift while the shallow side allows your secondary to continue to be able squeeze your belt as the secondary opens.
Now I was reading a resent post where someone saw low full shift RPM while racing. He made the mistake of twisting his secondary tighter to increase full shift RPM. By doing this it caused his belt to slip in the secondary, which raised his full shift RPM which really hurt him in the long run. In this case the rider should have number one felt his clutches. If they were cold there were efficient and making changes to the current components was useless in this scenario. If the full shift RPM needed an increase He could have done several things to increase it. If he was using a mass adjustable weight he could reduce the tip weight to increase full shift RPM. Now you must be careful because you could cause belt slippage in the primary by reducing the weight and you’d be back at the same affect as tightening the secondary.
The moral is, when you change clutching be prepared to make multiple changes based on snow conditions.
Also Snow conditions will dictate how efficient your clutching configuration is. Example a Drag race setup will not work well in deep snow. Your motor will bog. A deep snow setup will feel lazy in a drag race scenario.
So when you clutch your sled be prepared to make changes based on the conditions.
Basic clutch principles
Clutch fly weights: The Heavier the weight the lower shift RPM The lighter the higher shift RPM. Weight profile also dictates this as well as Roller.
Primary springs: the Heavier preload a Primary spring has the high the engagement. As you lower the preload you will lower the engagement
Primary springs: The heavier the total force on a primary spring the higher your full shift RPM will be. As you decrease the total force on a spring the lower the full shift rpm.
Secondary springs: Secondary springs are a tough one. Yamaha Secondary springs are rated by torsion twist. The Polaris silver blue is rated with side pressure. You don't put a tone of twist to it to make it affective. With Yamaha springs, if you want a ton of back shift you increase the twist. If you want more up shift you decrease the twist.
Helix angles:The steeper the angle, the faster the shift, the shallower the angle the slower the shift.
Subject
Drag Racing
I like to run as heavy a weight as possible and engage as high as I can with out blowing the track out. By doing this you have to watch the helix you use because you will pull the motor down with a super steep helix. Generally I've found drag racers like to use a steep initial angle helix with a shallow finish angle. The reason you do this is the steep angle increases the up shift while the shallow side allows your secondary to continue to be able squeeze your belt as the secondary opens.
Now I was reading a resent post where someone saw low full shift RPM while racing. He made the mistake of twisting his secondary tighter to increase full shift RPM. By doing this it caused his belt to slip in the secondary, which raised his full shift RPM which really hurt him in the long run. In this case the rider should have number one felt his clutches. If they were cold there were efficient and making changes to the current components was useless in this scenario. If the full shift RPM needed an increase He could have done several things to increase it. If he was using a mass adjustable weight he could reduce the tip weight to increase full shift RPM. Now you must be careful because you could cause belt slippage in the primary by reducing the weight and you’d be back at the same affect as tightening the secondary.
The moral is, when you change clutching be prepared to make multiple changes based on snow conditions.
Also Snow conditions will dictate how efficient your clutching configuration is. Example a Drag race setup will not work well in deep snow. Your motor will bog. A deep snow setup will feel lazy in a drag race scenario.
So when you clutch your sled be prepared to make changes based on the conditions.
Jason...increasing the secondary spring pressure will increase grip pressure to the belt thereby slowing upshift. This in turn will stop the belt from slipping. By going to a steeper helix or decreasing the secondary pressure with a weaker torsion spring or less wrap you decrease belt pressure & this will cause the belt to slip or get sucked down into the secondary. You want to run just enuff helix & secondary spring to stop the belt from slipping in the secondary for best efficiency. It is better to run a little less helix or a little too much secondary spring pressure then the opposite.
Bob Miller
TY 4 Stroke Master
- Joined
- Apr 19, 2003
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- 1,322
- Location
- New Milford CT
- Country
- USA
- Snowmobile
- Present Sled: 2011 Yamaha Apex 128
How about what Sketr2 did to his Warrior that greatly improved performance, here is his information and results: The testing went on for several rounds and everyone was happy and came back to the cabin and verbally worked me over. We agreed that the RPM on the warrior seemed low so we tightened the secondary up about 20 degrees above stock. The maintenance RPM climbed to 9800 until about 50 then crept to 10000 and finally to 10200 on a top end reading of about 130 on the speedometer.
We lined up again and the warrior was next to the F7. The warrior pulled 2 lengths out of the hole and increase the lead to about 4 lengths at 110 plus. The warrior was still pulling at the end of the run. The F7 and REV were side by side all the way. Several more runs were made with the same results. Now I don’t have to take crap from the puppies any more.
We lined up again and the warrior was next to the F7. The warrior pulled 2 lengths out of the hole and increase the lead to about 4 lengths at 110 plus. The warrior was still pulling at the end of the run. The F7 and REV were side by side all the way. Several more runs were made with the same results. Now I don’t have to take crap from the puppies any more.
RedRider
Newbie
- Joined
- Nov 29, 2003
- Messages
- 15
There was an exellent article in the last issue of Snow Tech. It would be nice to copy it some how and post it here.
Turk: excellent post. turk is right you want just enough twist so your belt doesn't slip
Mike do you agree that to much twist is bad for a drag race situationunless your looking to only trail ride and want sick backshift.? How about it's a bad practice to try to gain Full Shift RPM by increasing twist on the seondary?
a perfect exsample of this is RXwarriors MC turbo sled. He was twisting the hell out of his secondary and his clutches were on fire. we made some changes that included decreaseing twist. Everytime we derecesed the twist the secondary cooled more and more. Until it was only warm to the touch.
Mike do you agree that to much twist is bad for a drag race situationunless your looking to only trail ride and want sick backshift.? How about it's a bad practice to try to gain Full Shift RPM by increasing twist on the seondary?
a perfect exsample of this is RXwarriors MC turbo sled. He was twisting the hell out of his secondary and his clutches were on fire. we made some changes that included decreaseing twist. Everytime we derecesed the twist the secondary cooled more and more. Until it was only warm to the touch.
Bob Miller: if his sled was 100% stock then I'd say no. I'd have to know what setup he was running.
Jason....the secondary clutch tuning issue is really a snow condition-traction thing. For racing on hardpack you can run a huge helix with very little secondary twist. When condition deterioate & the track gets chewed up you gotta tighten up the secondary or go to a lesser helix. For trail riding you will want about a medium agressive helix with about the same for a torsion spring. You want good accelleration but if you need to back off the throttle & peg it again you want the rpm,s right there! For mountain riding you want a shallow helix with lotsa secondary twist. You need some serious downshifting for deep snow & hillclimbing....ie...keeping the clutches in a lower gear ratio for a long time.Bottom line is ...lota helix, less secondary tension = fast upshifting with very minimal backshifting & not much belt pressure. Shallow helix with a stiff secondary set up = slow upshifting with very quick backshifting & a lot of secondary belt pressure. Now to confuse the issue you bring into play the primary set up which you must balance with what ever you are trying to accomplish in the secondary!!!! Bottom line is test & tune for your own individual prefernce, conditions, & enviroment. There are a kazillion different clutching combo,s to get you to desired rpm,s & in any given day one set up will destroy another set up even tho they both hit target rpm,s. Man..I could go on for ever but I gotta go sell some toilet paper!!!!
Turk: So we argee 
hey can you post a couple different riding condictions and pick a sled and build a clutch package for them. That way people can see how conditons affect the clutching.
hey can you post a couple different riding condictions and pick a sled and build a clutch package for them. That way people can see how conditons affect the clutching.
Bob Miller
TY 4 Stroke Master
- Joined
- Apr 19, 2003
- Messages
- 1,322
- Location
- New Milford CT
- Country
- USA
- Snowmobile
- Present Sled: 2011 Yamaha Apex 128
jtssrx, I believe he said in his post; this is a stock Warrior except for studs,
But what amazes me is the performance gains, He made mince meat out of the REV 800 and the F7
But what amazes me is the performance gains, He made mince meat out of the REV 800 and the F7
4Fighter
TY 4 Stroke God
Great topic but my head is starting to spin.
Personally, I think the RX1 stock setup is pretty good - compared to what? For out of the box, I've never had a sled that pulled that hard for that long. Sounds like you guys know what your talking about though, and are eager to help us less experienced tuners :wink:
Keep up the good work! 8)
but my head is starting to spin.Personally, I think the RX1 stock setup is pretty good - compared to what? For out of the box, I've never had a sled that pulled that hard for that long. Sounds like you guys know what your talking about though, and are eager to help us less experienced tuners :wink:
Keep up the good work! 8)
OK...here is one scenario when i had my piped ported 700 sx-r. On hardpack i ran 89L weights with a 47/39 roller rooster with green spring at 60. This roller shifted like a 54/44 conventional helix. It ran great on real hard pack conditions but if I hooked up particularly well it would suck the belt into the secondary & die. It would also lose acceleration in soft mushy conditions even tho the rpm,s remained fairly consistent. Also running this combo in powder was impossible....it would not even run.I could fix this by running a silver secondary spring at 60-70 or running a 43/39 roller helix & adding some primary weight. If I went back on hardpack I would lose some acceleration with the silver spring or 43/39 helix. In general if you are running real hard pack conditions & don,t need backshift run as much helix & the softest secondary spring the sled will handle. If you are gonna run sloppy conditions a band aid would be to tighten up the secondary spring but you lose efficiency doing that. Best fix is to run less helix & keep secondary spring pressure close to stock. Also to remember that not all helix,s shift the same. There are a few different ways of cutting em & measuring angles. Some buttons start at different spots on the helix & that will change the way they work too. Way too many scenarios out there...just gotta go play!!!
thanks Mike
Thanks Mike.
Hey anyone else whos go quesions or wants to post a topic or maybe ever a senario for Mike or maybe me to try to give you a setup please post!!!!!!!!!!
Thanks Mike.
Hey anyone else whos go quesions or wants to post a topic or maybe ever a senario for Mike or maybe me to try to give you a setup please post!!!!!!!!!!
vmaxjohn
Pro
I'll comment on how the Warrior did better with more secondary twist...
for those conditions, which to me sounded like fresh, loosely packed snow over ice (alot more drag and resistance than shaved ice for example) the Warrior was shifting into high gear a little too soon. If the rpms don't achieve optimal rpm (10,200rpm?) until you run out of room, then it means the clutches are shifting up too much for that condition.
If by tightening up the secondary, and slowing the rate of shift a nudge, the rpms jump to 10,200 (or close mind ya) and stay there till top speed, it means that the clutches are taking advantage of the traction available, and aren't shifting up too quickly.
If your secondary is too loose for conditions, this can occur. You take off across a lake with some hard packed snow, some fresh snow. Your rpms are ok, a little under (meaning you're loading the engine very hard) and when you hit some fresh snow the rpms go UP. The secondary felt the load increase, and tried to downshift when all you wanted was to go faster.
When I clutched my sled, I went from an over rev situation (400rpm typically) to an under rev. I'd added 4.8 grams of mass to the primary, and loosened the secondary 10* at the same time. I couldn't go over 75mph! I was spinning 7000, 800rpm under my target. I would start from a stop, rpm's would be pretty good, then I'd hit high gear and they'd drop all the way down to 7000.
I put the secondary back where it was (tighten 10*) and wow! I had backshift and my top end went to 103mph on the speedo. This small adjustement meant that my clutches were now working together, with CLOSE TO THE SAME RATE OF SHIFT in both primary and secondary.
This is something I haven't ever found in an article. Having the primary and secondary shifting at close to the same rate means you will have the best acceleration possible. It's when we get the primary shifting up quickly and the secondary too slow (or vice versa) that we get into trouble.
While getting into either direction might be desirable for a certain condittion (mountain riding like Turk said), if you get too far off, it's going to suck. Hot clutches, slipping belts, black rings on your clutches, bogging and getting stuck, or worse, getting beat by a John Deere Liquifire!
So, back to the Warrior in question. By reading through the information posted, it sounds like Sketr2 just evened out the rates of shift for those particular conditions.
He'll probably find that setting works great for trail riding too.
This is a great thread, thank JT!
for those conditions, which to me sounded like fresh, loosely packed snow over ice (alot more drag and resistance than shaved ice for example) the Warrior was shifting into high gear a little too soon. If the rpms don't achieve optimal rpm (10,200rpm?) until you run out of room, then it means the clutches are shifting up too much for that condition.
If by tightening up the secondary, and slowing the rate of shift a nudge, the rpms jump to 10,200 (or close mind ya) and stay there till top speed, it means that the clutches are taking advantage of the traction available, and aren't shifting up too quickly.
If your secondary is too loose for conditions, this can occur. You take off across a lake with some hard packed snow, some fresh snow. Your rpms are ok, a little under (meaning you're loading the engine very hard) and when you hit some fresh snow the rpms go UP. The secondary felt the load increase, and tried to downshift when all you wanted was to go faster.
When I clutched my sled, I went from an over rev situation (400rpm typically) to an under rev. I'd added 4.8 grams of mass to the primary, and loosened the secondary 10* at the same time. I couldn't go over 75mph! I was spinning 7000, 800rpm under my target. I would start from a stop, rpm's would be pretty good, then I'd hit high gear and they'd drop all the way down to 7000.
I put the secondary back where it was (tighten 10*) and wow! I had backshift and my top end went to 103mph on the speedo. This small adjustement meant that my clutches were now working together, with CLOSE TO THE SAME RATE OF SHIFT in both primary and secondary.
This is something I haven't ever found in an article. Having the primary and secondary shifting at close to the same rate means you will have the best acceleration possible. It's when we get the primary shifting up quickly and the secondary too slow (or vice versa) that we get into trouble.
While getting into either direction might be desirable for a certain condittion (mountain riding like Turk said), if you get too far off, it's going to suck. Hot clutches, slipping belts, black rings on your clutches, bogging and getting stuck, or worse, getting beat by a John Deere Liquifire!
So, back to the Warrior in question. By reading through the information posted, it sounds like Sketr2 just evened out the rates of shift for those particular conditions.
He'll probably find that setting works great for trail riding too.
This is a great thread, thank JT!
ttt
Great post guys!!
You wanted a scenario to work on? A challange? How about the RX Mountain?
With the mountain sled you turn 10,200-10,300 on the trail and then 9,600-9,700 when climbing in bottomless powder.
So convential thinking says it's not back shifting right? How do you fix that? I would think the secondary, but most everyone last year was going crazy with the primary.
You wanted a scenario to work on? A challange? How about the RX Mountain?
With the mountain sled you turn 10,200-10,300 on the trail and then 9,600-9,700 when climbing in bottomless powder.
So convential thinking says it's not back shifting right? How do you fix that? I would think the secondary, but most everyone last year was going crazy with the primary.
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