[SNODOGG]

I was thinking about the F7 and the fact that with the deep lug track it has a 53/51 helix. Why woudn't be the same for the F5, they stayed with the 51.

any thoughts, <_<
SNODOGG

 

[Bullwhip]

The 500 probably doesn't have enough snort to pull the 53.

-bullwhip

 

[CatzAzz]

Originally posted by Bullwhip@Dec 13 2002, 01:55 PM
The 500 probably doesn't have enough snort to pull the 53.

-bullwhip

My F5 is pulling a 62/50 and it pulls hard from the minute I grab the flipper to the second I let off

 

[sled-head]

Originally posted by CatzAzz+Dec 13 2002, 06:38 PM-->

<!--QuoteBegin-Bullwhip

@Dec 13 2002, 01:55 PM
The 500 probably doesn't have enough snort to pull the 53.

-bullwhip

My F5 is pulling a 62/50 and it pulls hard from the minute I grab the flipper to the second I let off [/b]

Well put in the strait 53 then LOL.............the 500 wont pull it on the top

 

[Bullwhip]

Originally posted by CatzAzz@Dec 13 2002, 06:38 PM
My F5 is pulling a 62/50    and it pulls hard from the minute I grab the flipper to the second I let off

I haven't ridden the F5, so I'm not doubting you, the 62 just sounds pretty extreme! Do you have it shimmed to quickly transition to the 50? How is the backshift, and where do you run the spring? I set up a POO XC6SP with a Cat roller last fall, and we had no luck with anything steeper than a 60-55.

-bullwhip

 

[Ron]

You should not compare the two sleds on clutching ( F5&F7).
The helix that you use depends on seveal items.
1- The weight and curviture of the drive clutch weights.
A heavier the weight, the chance is the less the helix angle you will be able to run, exspecially the second # on the helix.
2- The setup you are looking for, drag racing, snocross etc.
3- The conditions you usally ride in.

By shimming the helix it will not make a quicker transition to 50.
What you are doing by shimming the helix, you are moving the rollers down the curve, taking some angle away from your first number. Making it a 60-50 or a 58-50. Fine tuning the helix.

The way I like to set my sled up is put a middle of the rode helix in.
Then find drive weights that just let the sled over rev a little on an AVERAGE day.
Then go back a put a little more helix into it, using the driven clutchs spring location to adjust to weather conditions.

Generally you do nut want to steep of a helix unless you are drag racing because it is harder to back shift.

I like to set my sled up so when you hit the gas out of the hole , the rpms run right around your high torque point, then creeping up to your high Hp point by 3/4 to the finish of the race or maybe a small over rev.

Again different lenght races, weather conditions, and snow conditions will all play a factor in how you need to set-up your clutchs. Finding a happy median is key for a trail sled.

On a closing note before you even think about changing your clutching, make sure your clutches are lined up right with little belt deflection. I have seen so many sleds lose with good clutch set-ups because of the basics. A loose or worn belt is like starting in 2nd gear in a race, and having no over drive.

 

[Roy T]

Excellent post Ron -- good info, and good advice! -- Roy

 

[Bullwhip]

Good basic info Ron- However I disagree with your take on the helix issue. Adding a shim to the helix places the rollers further down the ramps on the helix, it does not change ramp angle unless it is shimmed to the extent that the rollers are on the transition portion of the helix. In addition, starting furtner down the helix will result in the rollers quickly moving from the 1st angle to the 2nd on the helix as the moveable sheave opens. Since the rollers and the moveable sheave move as one, the position of the helix, as deterimined by shimming, effectively determines how long the rollers spend on each portion of the ramp.

 

[F7 Firecat]

Anyone know where I can learn more about clutching for sleds. Any books websites etc. I would like to learn more if possible.

Thanks

Bryan

 

[Bullwhip]

Originally posted by F7 Firecat@Dec 14 2002, 10:29 PM
Anyone know where I can learn more about clutching for sleds. Any books websites etc. I would like to learn more if possible.

Thanks

Bryan

Olav Aaen has published lots of good stuff. You can get his books through lots of snowmobile parts places like Dennis Kirk or Shadetree, or call Aaen Performance direct at (414)552-8981

-bullwhip

 

[Slider79]

I had a standerd track. Traded for a snopro track. Will I loose power because I have the standard helix. And will the guy I swapped with gain the power?

 

[LUVMYF7]

You guys should trade helix's also.

 

[Ron]

Bullwhip, I don't know what type of multiangle helixs you are using, but all the good machined ones have a transition with in the machining that you can not see, changing the angle as you go down the curve. I have seen some poorly machined ones that you can actully see the the step where the change angle, I stay away from them. So in turn if you shim the back of the helix you are starting down the curve or at a smaller angle.
I hope your rollers are hitting the helix in the begining. Read what you wrote about your moveable sheave, it still has to move the same distance as before (the clutch opening) because the belt is the same width and the clutch has to open to get full range. Hence the rollers traveling the same linear distance to open the clutch just in a different spot on the helix. What you are saying is your roller would not be at the bottom of the helix or the clutch would not open if you think it travels a shorter distance.

If you think those step helixs are good, how can you plan where they are going to be when your clutchs are changing 1000s of times or varibles when you ride. They may work better in a drag race, but still would stay away from the and get a good machined mutiangle one. <_<

 

[Bullwhip]

Originally posted by Ron@Dec 15 2002, 09:19 AM
Bullwhip, I don't know what type of multiangle helixs you are using, but all the good machined ones have a transition with in the machining  that you can not see, changing the angle as you go down the curve. I have seen some poorly machined ones that you can actully see the the step where the change angle, I stay away from them. So in turn if you shim the back of the helix you are starting down the curve or at a smaller angle.
I hope your rollers are hitting the helix in the begining.  Read what you wrote about your moveable sheave, it still has to move the same distance as before (the clutch opening) because the belt is the same width and the clutch has to open to get full range. Hence the rollers traveling the same linear distance to open the clutch just in a different spot on the helix. What you are saying is  your roller would not be at the bottom of the helix or the clutch would not open if you think it travels a shorter distance.

If you think those step helixs are good, how can you plan where they are going to be when your clutchs are changing 1000s of times or varibles when you ride. They may work better in a drag race, but still would stay away from the and get a good  machined mutiangle one. <_<

I wasn't suggesting the moveable sheave moves less if the helix is shimmed. The fact that it must move the same distance is exactly my point. I use a few different multi-angle helixes including Arctic Cat, Black Magic and some custom grinds. Most of them you can not see the transition, however if you place a straight edge on the helix, you can see there is a portion of transition, and two distinct "straight" areas. If the helix was cut such that the ramp slowly changed from the beginning number, say 60, to the final number, say 50, an unshimmed helix may never hit the 50. Obviously, the rollers travel the same distance regardless of the amount of shimming, so if you are hitting the 50 without shimming, you will hit the 50 quicker with a shim. Anyway, what ever you are doing works for you, and that's what matters. What are you riding this year? I picked up a standard F7, in black a couple week ago, but haven't been able to ride yet due to the lack of snow here in central MN. If you're on an F7, I'd be interested to know what you end up with for clutching/gearing.

-bullwhip

 

[sled-head]

I think you are bolth correct............It all depends on how you look at it. If you shim your helix you will run a shallower start angle and obviously hit the second angle sooner........the second angle is lowered as well because if you run a 53/51 you are not likely hitting the 51 angle without a shim and are at a 52 or very close to it...put in the shim and you will hit the 51..........

 

[Ron]

F7 Black Sno-pro.
Haven't had much time to test yet, lack of snow as well.

I'm studded with 150 woodys.
Pushed the centers to tighten up the belt delection.
Going to start with a 55 degree helix forth hole. We run close to sea level here so our motors usally make good HP.
I really need to get her broken in first to see if she will pull the 55.
I usally start with stright helixes to see where I can go with the top end rpms.
If she will pull the 55, might back down on the helix and add a little drive weight. That way I can still get good back shift.
Depends what I can find for weights, don't mind grinding them but I like finding a good adgressive curve the also has the same back profile to make sure I get the back presure, no slipping.
If she does not pull the 55, I will back down to a 53 and try a multiangle to see if it can pull some out of the hole. I have a good feeling that she will take a ton of clutch.
I like to run the driven a little tight, that way I have room to adjust as the weather and conditions change.

How about you?? <_<

 

[Ron]

Oh I'm leaving the stock gears for now.

 

[sled-head]

I am going to try a 57/50 or a 55/51....stock wieght..... orange/white cat primary and gear it up to 23/40

 

[Ron]

Why are you going with the orange/white spring? To raise your engagement?

 

[sled-head]

I wiegh in at 215lbs and if I gear it up it might bog out of the hole. so If I bump up the engagement i figure it will compensate for the higher gear ratio.........I played around with my F7 stock and it felt like it ran out of gear