670\ Ho - Clutching Problems

[Walrus]

ARRRGGG! I had a nice long reply typed out.. pressed the wrong button.. lost it all. I'll have to type shorter and faster this time:

I thought multiangle stock helixes like my 53/47 change angle suddenly in the middle. Pretty sure I can see this when I have the helix in my hand. And, I run 7400-7500 until 80 km/h, then quickly hit 7900 and stay there until I back off, which backs this up.

I can see how changing to a progressive wide angle helix would help me.. wouldn't be on the 53 as long.

Only things changed this year: Stock pins (~16g) changed to heavier adjustable pins (~18g), and stock 200-290 spring changed to 200-320. I have noticed more acceleration from 80km/h and up compared to before.. flys right to 165 (on the speedo). Seems slower off the line though, used to be right at the flap of my buddy's clutched SRX with roller secondary, then start loosing ground as the speeds increase. Now, I am immediately 3 lengths behind, then stay there, and then start gaining on him a little.

Questions:

Can get a 53/40 (maybe not low enough finish), 52/44 (not low enough finish), or 50/38 (maybe to low a start angle) from Royal Distributing. Or.. the Doo 53/37 you mentioned, got a p/n? Or.. something from Dalton.. price seems a little high though at $123.95, plus tax, plus shipping.. but could get a 53/36 or 52/34.

Your recommendation? I only want to end up buying 1 helix. I WILL KEEP NOTES.

Why do the small screws go in first? Easier to vibrate loose and fall out if they aren't?

Heard it before, and it says so on the Dalton site: Only run the longer adjustable pins (which I have) on clickers 4,5,6. Is that at all times, or only when hanging out a set screw to get more weight in?

[H.O.RIDER]

Great stuff guys!!! Very interesting.
Walrus- Keep in mind the 297 ramp seems to like lower clicker settings rather than higher. I believe places like the CrankShop use to recut stock helix's quite cheap.
You could get your 53-47 recut and try it to see how you like the way it responds.
I have tried as much as 20g with the 297 with a 230-350. In the secondary it worked best with a 43-40 holeshot Black Ice. This setup was very fast in a drag situation. Not the best on the trail.

[Walrus]

Originally posted by Dynamo^Joe@Jan 20 2004, 08:19 PM
I am not sure of the angle measurement thingy. With a piece of paper, I have wrapped around a 44 HRP black ice helix and a Skidoo 44 helix. HRP has mentioned they measure different than skidoo so the angles are supposedly off. Well I traced out the helix button/roller path on both then measure with a protractor and both produced about 45 deg angles.

What you are doing, is measuring at the outside. You will measure less angle there.

Think about this: If you drew a line on the helix ramp face at the outside, and another right up the middle.

Both of these lines have travelled the same distance vertically.. but the outside line, being at a further radius, has travelled further horizontally. Rise/Run, the outside will measure a lesser angle.

Some manufacturers claim they measure at the outside, while Ski-Doo measures at the inside. IF they do, the angles will measure different. However, I don't see them being 4 degrees out. Today at work, I'll model up a helix in 3D, and do this measurement on the computer. I'll come back tonight with the results.

[Gasoline Man]

I don't mean to be too critical of you Walrus - but, man your all over the place. Here's my two two cents. Some one name Joe once told me if your content with try out what works for others, then you'll aways be an mediocre tuner. It's fine and dandy to know what others are doing but, you ultimately have to test it if you really want to make it work for you. Even though tuners test one change at a time you have to be aware of the entire set up, from engine to clutching, gearing, track and suspension, and how they react to each change.

Sorry I don't have any constructive suggestions. I just know the 670 HO rocks when its tuned properly.

[Walrus]

I modelled up 1/3 of a helix (one ramp). Made it 4" diameter, with the ramp 3/16" wide (I figured the ramp is 3/8 wide, so 3/16 would allow me to measure the arc length of the middle of the ramp). I made it 45deg, with a 1.25" vertical height and 1.25" horizontal travel (along the circumference) at the outside. Horizontal travel the the middle is 1.145". tan^-1 (1.25/1.145) = 47.5 deg. Confirmed this measuring the actual arc length up the ramp, and more calculations (sine instead) resulted in the same degree difference. If someone gave me the actual diameter of a Ski-Doo helix, the ramp width, height of the ramp, and where the ramp ends in degrees if the start is at 0, I can get you the exact numbers.

Gasoline Man - the only thing that is all over the place is your grammar Just kidding.. don't take offence. "If you try out what works for others, then you'll aways be an mediocre tuner." Sorry.. experience does go far, but to me, knowing the theory first and then when you apply it and understand why it worked.. that goes further. Testing and testing and testing to eventually find the best result tells you nothing, if you don't understand first what is happening with the clutches. I now know what will happen if I apply most of these suggestions, so I am just looking for from others, what works best for the HO. I now question all those who have said the following: Stock ramps, 18.2g weight, 200-320 spring, stock secondary spring, and straight 50 or 50/47 helix. Maybe they were just selfish and didn't want to give up their secrets, or that's as far as they went. Once I do find what works best for me on the HO, I'll be returning here to post details of what I did, what I used, and what the results were. If others want to use that, and not try to understand why it works, that is their perogative. I know I will still learn a great deal, even if someone hand feeds me the best setup for the HO. End rant.

[Gasoline Man]

Hey good Rant. Your right about my grammar as English isn't my first nor favorate language.

I kinda agree with you. The theory and the testing go hand in hand to understand what's going on. But, real world data sometimes contradicts what was calculated on paper. That's why I value the "real world data" you get from testing more then the theoretical data.

Any who... You and Joe had a great thread going near the end there. Good luck.

[Dynamo^Joe]

Walrus]...I thought multiangle stock helixes like my 53/47 change angle suddenly in the middle. Pretty sure I can see this when I have the helix in my hand. And, I run 7400-7500 until 80 km/h, then quickly hit 7900 and stay there until I back off, which backs this up.

Where the angles of a helix are more than 45, the length of those angles is shorter than 45 or any angles less than 45.
The steeper the angle, the shorter the path for the roller/button to travel per degree.

Less than 45 degrees, the angle's attitude is more laid down. The length of the roller/button path becomes longer per angle. The helix itself is a merely a rectangle wrapped in a curve. Being as this is, at 45 degrees on a multi helix this is where the transition is of where you start to see a visual dip on the path.

When a helix is drawn up, each angle is a chord of a series of circles. Each angle is a little chunk of a different diameter circle. Blend all the little chunks together in the confinement of the helix size...voila. A parabolic curve that the roller/button runs down.

don't pay attention to the paragraphs written on the page. This was quite a long time ago when I wrote that up. There is a much more accurate description where one day i'll post.


Walrus]...50/38 (maybe to low a start angle) from Royal Distributing. Or.. the Doo 53/37

Buy the most economical helix I guess. If it's coated, I would want the hub that mounts on the stub...want the mount to be coated also so it resists deforming like plain aluminum does under stresses from running.

Walrus[...Only run the longer adjustable pins (which I have) on clickers 4,5,6. Is that at all times,

You can run them right down to #1 clicker and clear. When you start to stick more than 4 threads out there will be contact with the governor cup.

[purple punisher]

Wlarus, I think if you are going to ask for Joes help and will take notes and test properly........then why not buy the helix from him. Everyone on here is quite happy with his stuff. He has had a few different one custom made and probably has the one you need. $120CAN is the normal price for a helix..especially if it is coated. You may get one for $100 but what is $20. I'll bet if you spent the $ on Dynos, you would get that $20 back in questions being answered.

[Walrus]

Hey.. Joe, if you have a helix that you know will work on my HO, I'll buy it from you. I just thought you figured out what works for 440's and 800s, and now 600s.. then get those custom made for your kits, and wouldn't have one (or don't have one figured out) that would work best for a 670 HO.. that's why I'm on here looking for suggestions.

[Dynamo^Joe]

Guys...I hope you all did not think that I was answering this topic because I was interested in flogging something I made. To me Walrus was asking questions where I offer comments merely being somewhat of an "amateur editor". Sometimes I can't help myself. he he

I always just try to convey message to believe in your exercises and quit asking people what they run.
Be your own "Think Tank" after you measure what is happening with your sled. Ala...temperature, rpms, seat-of-pants, mphs, compare acceleration/top end to similar cc sleds.
This to me is the difference where learning can stop, or keep on going.
How many people say "tried it but it did not work", then set the part on the side to collect dust.
It did not live up to your expectation, but you did not try to make it work the best it could.
...I didn't do this because someone told me not to...i did only that because I heard...
Clutching by "guilt of association" sucks.

When you make something work the best it possibly can, you learn WHY it did not live up to your expectation. This is where you get direction to go next.
maybe then you only have to buy one more helix...or take a educated guesstimate that is in your favor and make your own helix.
Gather information...believe in your notes "they don't lie" and it is not here-say.

I have not worked with a button secondary in a loooooooong time. Two seasons ago I did so some work for an afternoon on a Formula 583 and made that bad boy beat up on some 700's. So I never really play with the 670.
I think walrus can go ahead with his curiosity of getting one of the economical helix he mention and in no time get it to work great...
...then when it works great, he will not only have answers, have good data and more questions than he thought he could have. The best thing will be that no one can tell him otherwise. he he he