one on ebay and was wonderin the effect it would have on my ski-doo....1998 mxz 500 with a 1.25 lug track. thanks

50/46 versus your stock 50

first,the upshift will remain the same since you are running the 50 degree. when then secondary gets too the 46 degree you put more pressure on the belt which in turn will give you a faster backshift until you get to the 50 degree. in the secondary, the smaller the angle the more the side force.

uncle neil

50/46 versus your stock 50

first,the upshift will remain the same since you are running the 50 degree. when then secondary gets too the 46 degree you put more pressure on the belt which in turn will give you a faster backshift until you get to the 50 degree. in the secondary, the smaller the angle the more the side force.

uncle neil
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thanks again uncle neil lol. so im guessin more side force = more grip which will = more speed???

more grip = less slippage, but when you reach the point where the belt doesn't slip, more force is just a waste. steeper angle helix = quicker upshift, or more engine loading. smoother angle helix = quicker downshift, less engine loading.

With a buddy of mine, we are playing with old 583, and our spare engine come from a 1990 mach1. The helix angle is steep (comparable to today's sled, but back in the time, it was very steep, 53° IIRC) and this is work well for this engine, when starting from stock clutch setup. On this setup, changing for a smooth angle helix clearly unload the engine. It feels very responsive, rev a lot, but doesn't accelerate. When the driven pulley doesn't shift quick enough, it make the engine overrev, and modification to the drive pulley are inneficients.


what should you feel with a 46/50 helix? the initial rev buildup should be quicker, and downshift at lower speed should be quicker too, slowly returning to original spec. since the "average" angle is less steep, your engine shoould feel a bit more responsive.

more grip = less slippage, but when you reach the point where the belt doesn't slip, more force is just a waste. steeper angle helix = quicker upshift, or more engine loading. smoother angle helix = quicker downshift, less engine loading.

With a buddy of mine, we are playing with old 583, and our spare engine come from a 1990 mach1. The helix angle is steep (comparable to today's sled, but back in the time, it was very steep, 53° IIRC) and this is work well for this engine, when starting from stock clutch setup. On this setup, changing for a smooth angle helix clearly unload the engine. It feels very responsive, rev a lot, but doesn't accelerate. When the driven pulley doesn't shift quick enough, it make the engine overrev, and modification to the drive pulley are inneficients.
what should you feel with a 46/50 helix? the initial rev buildup should be quicker, and downshift at lower speed should be quicker too, slowly returning to original spec. since the "average" angle is less steep, your engine shoould feel a bit more responsive.
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very imformative guys....im gonna pass up on tat 50/46 and buy a helix with say a 46/50 to keep it the same cuz im planin on puttin stock sprngs anyways....thanks guys

good luck trying to find a 46/50 helix

Actually several helix builders make a "reverse" angle helix, shallow start, steeper finish.

Remember, a STRAIT angle cam shifts harder than a compound.

It is hard to explain in works, but on a compound or progressive cam, they are somewhat shaped like a hockey stick, not strait from one point to another.

If you are running all stock clutching, take out the Ski-Doo beige secondary spring, and switch to a Goodwin White secondary spring, a EPi red, or even a Ski-Doo white (stock secondary spring on 01 800mxz).

They are stiffer side-to-side and will be more apt to handle that 1.25 track, and will help with backshift.

All the 50/46 is going to do is make the sled accelerate slower.

The 50/46 would not shift no where near as aggressive as a strait 50. If the sled is having a hard time dealing with the 1.25 track, it may be a good choice.

You would need like a 54/46 to be similar to that of a strait 50.

really

Goodwin Performance offers 10-12 reverse angle helixes for the Formula clutch (50/54, 44/48, etc...)

Worked good with 700 and 800 twins with the aggressive 280 TRA ramps that were used allot in those days.

i did not know that. good to know that option exists.

uncle neil

I would try the 50-46, not much different from the stock machz 50-47.
I have been playing with a 50-42 with good results, realy cool clutches, great back shift, really good trail helix.
For top end radar running on ice, i use a 47-50, it proved to be 3-4 mph faster then a 50-47 in 2500 + feet

comparing straight 50 to a 50/46

SWTE]...Remember, a STRAIT angle cam shifts harder than a compound.
Joe]...Remember, compound angles with finish angle less than a straight helix provides more "BELT CLAMP" at higher ratios.

Where you previous had low mph due to belt slip with a 50 finish angle
You will gain mph with the 46 finish angle because it clamps the belt...harder. :)

If I was going to run a helix found used on the net somewhere, i would run a 50/37 angle and add the flyweight required to keep the rpms stable from low to highest ratio.
The temperatures revealed will be cooler, the belt will have been clamped harder all the way to top mph. The engine will be responsive when running hard corner to corner or deep snow, the lower angle also compensates for hot pipe torque loss, which helps build engine rpms when needing the engine to accelerate.

Because of having to add flyweight to make rpms not drift higher, you get the added advantage of having flyweight to accelerate quickly off the start.

SWTE]...The 50/46 would not shift no where near as aggressive as a strait 50
Joe]...Need TRA lever to push harder?... add required flyweight.

I don't know why people would use straight angles and want to use less belt clamp where at high speeds, belt clamp is needed the most due to the smallest arc-area-of-belt-contact.

jmho :)

This is how I was tought on helix angles. Was to not pay attention to just the angle, but to look at how the angles effect how the clutch reacts.

I drew this up as a comparison.

In this pic, you see a strait 50 degree angle cam vs. that of a 55/45 cam. You can see the roller at the fully closed position, half way thru the shift, then at the end of the shift.

Given all variables are equil, you can see half way thru the shift, the compund cam has actually opened the clutch "less" than that of the strait 50 (1.4488" vs. 1.6872" on the 50 deg.). But at the end of the shift, you can see both cams finish much closer than they were half way thru the shift (3.2720" vs 3.2216" on the 50 deg).

Even though the compuound starts with a much steeper angle (55 deg vs 50) the strait 50 has opened the secondary more than that of the compound cam. The load divided on to the motor would be higher with the strait 50 (given it had the torque to open both setups)

you see, this is why this is the greatest site that there is,can be or ever will be

pay attention members,see what your missing, it only gets better as a supporting member.

uncle neil

Here, re-saved the file as a .JPG so it is much smaller file size.

I don't really know a whole lot, but I have been working on friends sleds now for about 10 years. I've installed a lot of clutch kits, different clutch parts, etc. I've tried changing just about every part of my clutches in my sled, and what I am running today isn't a whole lot different than stock.

The one thing I have found is that you can't just change the helix angle without changing a lot of things about how your clutches work. Everything works as a system. Change helix angles, and you'll more than likely have to change ramps and pin weights.

Helix angle is one of the LAST things I would change.

It's also very difficult to compare apples to apples when you're talking helixes. Different companies measure their helixes different, then there's also different coatings on them, which will effect things.

SWTE]...This is how I was tought on helix angles....etc...
Joe]...I do not disagree with anything you have mention on this page. I have only opened other doors to look in.

"Consider" other tasks that a helix performs...
Try to think with a term "required" angles for the particular application instead of using the words "big, small, large, etc...."

People are preprogrammed to think angles work only one way for all applications.
Break down all the facets of what the secondary does.
Facets being - the definable aspect(s) that make up a helix and spring and what they can do or what is required to do for the application.
Question - How do you find what is required for the application?

Can discuss a helix provides "shift" [upshift & backshift]
Helix also provides "Forces" [large forces, small forces - (Required) forces]

For fun, use 45 degrees as a median and not discuss "shift", rather discuss "forces"
Less angle than 45 = slower upshift, right???

Expand:
Consider - Angles less than 45 produce higher belt clamp forces.
Consider - Angles less than 45 DEcrease the time it takes for engine to flash from engagement to peak rpms. [in 10ths of seconds]

Expand:
More angle than 45 = quicker upshift, right???
Consider - Angles more than 45 produce less belt clamp forces.
Consider - Angles more than 45 INcrease the time it takes for engine to flash from engagement to peak rpms. [in 10ths of seconds]

How do you force a secondary open that has very high belt clamp? Make the primary clutch lever arm push harder.
Clamp belt in secondary very hard - Push secondary open by getting primary clutch lever arm to push and overcome the resisting force from the secondary.

..........................

SWTE]...The load divided on to the motor would be higher with the strait 50 (given it had the torque to open both setups)
JI]...To a point.

Too large of helix angle can reveal excessive rpms. At one point or another during the upshift, the primary can push the secondary open past it's governor point; The helix angle at-that-point on the shift ratio does not offer enough resistance clamping the belt.
The primary clutch pushes the secondary open, the sled travels at that speed by virtue of belt slippage in the secondary.
Temperatures will be incinerating. If the engine has enough torque, the rpms will drift higher and overrev.

Not low enough helix angle can eventually cause engine to overrev, the belt will slip at high revolutions across the clutch faces - This is especially seen on large bore or large cc triple engines where tuners keep trying to tune with helix angles that end up with low resistance to the push from the primary.
The state of tune is going past the governor point of the squeeze force on the belt...the belt slips excessively.

I have coached a cure to an example sled; 03 Rev chassis with a 1050 triple running a straight 50 helix, black 160/300 secondary spring.
The tuner started was trying to calibrate and lower the rpms by increasing helix angle, thinking that the larger angle will lower engine rpms.
Changing nothing in the secondary he kept going larger in flyweight, 21g, 22g, 23g, 23.5g and still overrev, in fact the heat was getting worse to spit sizzle on the clutches.
Disapointing not to break 105 mph with 200hp engine.
I got him to borrow a 50/40 helix from an 04 rev 800 and increase the secondary spring force from 160/300 to 225/300.
Now we built some belt clamp in the secondary. The temperature was proof that the secondary did not clamp the belt hard enough. The temp come back down and now actually break 110 mph with overrevving.
The overrev was caused from the resistance built up in the secondary from increased spring forces and lower helix angles.
Now have to overcome the high rpms.
We look at his primary spring and reduce the spring from 230/410 down to 230/380. The primary clutch lever arm pushes harder now and stop the overrev. If I remember right the sled is now running around with 22.5g lever arms and those secondary details help produce high 100 teens mph.

Same principles for Cats ???

I had 55/53 last year and then went to a 57/51

My rpm shift out went up 300 which was already a bit higher then it should have been

I got heavier weights too counter it this season

I feel the acceleration of the 57/51 was quicker then the 55/53 when switched,but never took full benifit as my revs where to high on shift out

I wish I would have tried something similar with my 583 but hindsight is 20/20

Principles are comprehensive so they are understandable by everyone which; Principles are fundamental law(s).
Does not matter brand. Only matters is CVT.

FB]...I had 55/53 last year and then went to a 57/51
My rpm shift out went up 300 which was already a bit higher then it should have been.
I got heavier weights too counter it this season

Joe]...I look at higher "rpm drift" as an opportunity to capture improved clutch efficiency.
If the rpms are raising then yes can push the secondary open with heavier flyweights.
If the rpms are raising then the belt is getting clamped harder...no? :)
If clamped harder then you should reveal lower temperatures on the secondary clutch.
Lower temperatures is more efficient system, but when acceleration decrease compared to previous run, then just look at the force numbers that push the secondary open. Im not one to increase helix angles thinking that secondary open quicker, as you read my comments over the years, i would sum up "why would I want to lower belt clamp" by that means?

Can also look at primary spring and change final force....
Example: 170/290 spring and you have rpms drift higher by 300 then can look at final force of primary spring and reduce it by 20 or 30 lbs. New spring to calibrate with would be a 170/260. You reduce 30 lbs of spring force that is resisting the push of the flyweight lever; The flyweight lever pushes harder now and will force the secondary open where you had higher drifting rpms.

When I get asked "What does a Helix do" I really have ever to been able to come up with one quick comment "It divides the load of accelerating and moving the sled that the engine "SEE's""

I agree on two loads; i)push from engine ii)ground load [for lack of better description]
The helix takes part in evaluating the push from the primary Vs the ground load.
Whatever combination of [spring/helix], they together look at the shape of the power delivered from the primary clutch and look at the shape of the ground load [your purpose]

guys go easy, you have to take the tangent on your helix and compare it to impendance. the more impendance or the greater the tangent the slower the backshift. the fellow simply asked what his helix would do.

uncle neil

edit: experience is a wonderful thing,no insult to anyone. the helix is reading torque from the track not the engine when it is backshifting. it is your responsibility to have the proper helix installed not the sled's.

uncle neil

I like to think of it like the gears on a bicycle. The helix angle controls the amount of time it takes for those back sprockets to go from 1st gear to 7th gear. Too steep of an angle, and it'll bog the engine down. To shallow of an angle and it will seem like there's no load on the engine.

ya there's lots of graphs,lots of herios, and the such, but when you boilit down. a tall helix shifts hard but does not backshift worth ####.a shallow helix will raise your rpm by the certain amount on wot and will backshift because it is reading the torque from the track or ground for that matter.this is meat and potatoes people

keep in mind, there are other factors to consider also. it's just not put in a helix and run with it.

the reason why roller secondaries work so good is not because of the lose of friction only, it's because we deminished the friction and more importantly the impendance. this is what i have bin taught.the first time my 800 backshifted, i dam near went over the hood.

clutching is not as simple as it seems.and you'll notice that those that are playing with their clutches are usually out front.

uncle neil

and as far as i'm concerned, there is not a whole lot of difference between any of the sleds each and every one of us ride. they are all one heck of an engineering accomplishment,one too be congradulated not kicked down.further, if i have have tried to hurt one sled from the other, i am truely sorry. we are all gods creatures. my appologies,please forgive old uncle neil