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Post by stinger440 on May 17, 2017 10:30:57 GMT -5
To be honest, I have no clue on the spring. I have some springs and I just pop em in and see what happens. The initial rate is what gives engagement. I do know the 300lb zone engages in the 5000 rpm range (depending on weights and profile) Try what you originally ordered first and see if you like it. Then you can tweak from there. Springs are pretty cheap at swaps. Any setup you read posted by OBJ is for the trail. He ain't giving up any racing set ups
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Post by weverat on May 17, 2017 15:06:06 GMT -5
Rene, The shim washers against the spring do cause a little more pre-load and a touch more engagement, but I never mess with that. The shimming I refer to is the shims to accomodate differant belt widths. Sometimes when you add shims to fit a 1 3/8" belt, you wind up tucking the weights, which can bring the engagement way up. All them dam clutches and weights are different. Sometimes the clutch bottoms out against the weights, other times against the shim washers. You have a good set up coming, just a final tweak, and you will love it. The adjustable weights are real thin, and hard on the rollers (not good for trail riding) but for drag racing they are real handy because you can add, delete,or move the weight around. You would really have a lot fun with them, as you can quickly make a huge change and see what it does (I learned a bunch about clutches by messing around with adjustable weights). The ones I use come from Thunder Products, they have a must read free clutching manual. thunderproducts.com/wp-content/uploads/2013/09/Clutch-Manual-2013.pdf I have had good luck with the TSK-100, they cost $100 for the kit.
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Post by weverat on May 17, 2017 15:14:08 GMT -5
You see with drag racing it is paramount to hit your desired engagement and top rpms, but also we must be able to adjust the shift speed.
We want that dam thing to go to top gear asap with out bogging the motor, but almost bogging, as to fully load the engine. Back shift is never considered.
I am following this thread, as I have never set one up for trail riding, you are the man!
Enjoy that Comet.
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tkjoe
L3 The Proven Snowmobile that never lets you down
Posts: 117
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Post by tkjoe on May 17, 2017 16:07:50 GMT -5
I was contemplating using a Polaris P85 clutch on my 78 TK? anyone know what set up to use?
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Post by weverat on May 17, 2017 17:09:57 GMT -5
tkjoe, You can use the exact same set up as Rene, the only difference is the Polaris clutch will be set up for a 1/3/8" belt. You need the grunt tools and a blow torch to un thread the spider and remove 2 shims in order to fit the 1 1/4" belt.
Ok, this tucks the weight a little, and will cause more engagement.
On one of my old scorps with the Polaris clutch, I shimmed open the driven pulley a tad to accomodate the wider belt, and this worked good too.
What I did was remove the snap ring, then drilled and tapped the end of the driven pulley shaft. Tossed the snap ring and used a bolt to hold it all together. All sorts of crazy shit like this happens in my shop!
The Polaris clutch is bigger diameter than the comet, so you will not use the whole thing, I mean the belt will not make it all the way to the top.
But the Polaris is bigger, stronger,and better built than the Comet.
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Post by 80sting440 on May 17, 2017 18:03:27 GMT -5
Hey guys, I really do appreciate your help. I found the spring chart and my head is itching even more!!! It's a good thing I ain't got any hair left to rub off . I've got the spring rate thing figured out (lbs at engagement and at shifted out point). The shape of the arms, I can make some sense of that. I may have limited experience playing with snowmobile clutches but I have modified the heck out of scooter ones with great success. There are a lot of similarities with some differences here and there. Some differences from some of you racers in the know that I have to keep in mind...back shifting for true trail/deep snow/ditch riding along with good fuel economy or racing my friend's '75 TX440. I'll probably have two setups, one for civil riding and another for when I ride with my TX buddy!
I'm looking forward to the challenge ahead.
Rene
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tkjoe
L3 The Proven Snowmobile that never lets you down
Posts: 117
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Post by tkjoe on May 17, 2017 20:01:41 GMT -5
Thanks Weve!
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Post by 80sting440 on Jun 27, 2017 11:58:59 GMT -5
I've got it set up with a Dayco 3014, which is 43 1/2 x 1 1/4.
I added a narrow shim, 1/32, between the secondary sheaves to accommodate some of the extra belt width .
I'll report back this winter on how this setup works out.
Rene
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Post by weverat on Jun 29, 2017 17:24:41 GMT -5
Yes, I like using the full 1 1/4" belt too. The belt winds up riding a tad high in the driven pulley, and it works good. Some how OBJ runs worn out super thin belts, but with great success! He definitely has some top secret shit going on.
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Post by 80sting440 on Jun 29, 2017 18:16:53 GMT -5
Yes, I like using the full 1 1/4" belt too. The belt winds up riding a tad high in the driven pulley, and it works good. Some how OBJ runs worn out super thin belts, but with great success! He definitely has some top secret shit going on. Maybe he has a side job with the C.I.A., F.B.I. or the Royal Canadian Mounted Police, eh?
Rene
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Post by weverat on Jun 30, 2017 6:47:19 GMT -5
Collusion with the Mounties.
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Post by obj1 on Jul 11, 2017 16:37:14 GMT -5
You guys are too funny!! Now remember, coming into Willow River this year, we are the defending D-STOCK champs. The Merc guys, the Rupp-sters and the Yamaha racers do NOT want to let a Scorpion win it again!! Last year it was 2 mercs, a exciter and our TK in the final. So....send me your worn out belts and some old race gas and we will at least let em know we are there!
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Post by 80sting440 on Sept 24, 2017 12:08:11 GMT -5
I took my sled out for a grass test run yesterday.
My clutch engagement is spot on for me.
As far as the weights go, I'm not sure as I'm not used to running on grass in the summer.
I don't have a tach and the engine surely has enough revs. I realize that high friction on the skis may prevent the clutches from shifting out.
I may have to temporarily install a tach or switch back to my to my newly rebuilt stock clutch and compare back and forth...I'm so impatient. Can't wait for snow.
Rene
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Post by 80sting440 on Oct 5, 2017 10:37:51 GMT -5
I was able to find a set of new k2 weights on eBay. As a few of you have pointed out, these are the recommended weights by Comet. Also as pointed out to me, the heavy tipped weights should prevent over revving and give the belt a good squeeze along with good upshifting.
Thanks again for the good advise guys!
Rene
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Post by weverat on Oct 5, 2017 17:13:35 GMT -5
The weights that have a lot of curve are very aggressive, and have a tendency to begin to shift too soon, causing a bog. This may not be noticeable on the snow as your track is spinning out. When you run on grass or ice with studs you will have this problem.
The straighter weights will allow the rpm,s to come up a little higher before beginning to shift, or you could say they hold you in first gear a tad longer.
When you have a ton of traction, these clutches can begin to shift to soon, and your engine will not be able to pull the load or catch up, and there you are draggin ass at 6500 rpm, and the power is at 7200 or 7500. This is epically true when tuning a modified sled with a very tight power band. We do not have this problem with our stock Cuyunas as they have good ! bottom end grunt and will pull hard from 4500 and up.
Those weights with the big curve need to be lighter and or have a heavy spring. What I am saying is, cam arms can weigh the same, but act way differently if they have more or less curve.
I keep all my cam arms separated by shape, then I adjust the weight and spring as needed. If I change the shape, then I start all over with weight and springs.
I try to use a spring that gives the desired rpm through the shift, and then adjust the engagement by grinding a notch.
Ok, all that shit said, I only have 2 different shape cam arms, I know they made a lot of different shapes over the years, but it seams almost all of them fit either a curved pattern, or not as curved patern.
Rene - If you get that thing to pull like gang busters on the grass, you will love it on the snow!
Let us know how it goes
Hang in there
WeveRat
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Post by 80sting440 on Oct 6, 2017 6:37:15 GMT -5
Hey weve! That's great insight . About the only things that I had figured out were tip weight and engagement notch...thanks to some tips from you guys. I can now visualize how that curve affects shifting. You've now removed that part of the mystery for me...Thank you.
When I first started this journey, I'd stare at the cam weights the same as when my wife drags me into a "home" store and asks that question, "which flower pattern do you like best?"
WHEN IS THAT SNOW COMING?
Rene
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Post by 80sting440 on Oct 6, 2017 9:01:10 GMT -5
With all of this said, I love how my stock Power Thrust II works. I just want to have the Comet copy that one. I don't need to re-invent the wheel...silver spring with k2s is Comet's recommendation and that's what I'll settle for. I've got enough parts to rebuild the PT II one more time, so either way, I'm all set for many more happy trail miles.
Rene
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Post by 80sting440 on Nov 8, 2017 19:34:51 GMT -5
My $.02 I think you are going to want a little higher engagement then the silver spring will provide. In my experience with these, the cuyuna with scorpion secondary like a heavy tip weight Like the K weight. I have tried using modern Polaris 10 series weights, they take off great but seem flat on the top end. The base combo you ordered might be fine for what you want. You're right Stinger.
The initial engagement rpm is fairly low.
For any kind of racing or aggressive starts, it's probably too low.
I got a chance to try it today on snow and actually prefer it this way...maybe I'm just getting old!
I'm also liking my A1 48.5 gram weights.
Maybe I'll install my K2 set next year to check out the difference.
Rene
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Post by weverat on Nov 9, 2017 7:06:35 GMT -5
Looking at Comet book, I see the K2s for 80 Sting, and B-1 for almost all of the Stings, TKs, and Whips. And then they have F-2 for the 340 Whips.
What is the difference between the K2, B1, and A1
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Post by 80sting440 on Nov 9, 2017 16:19:58 GMT -5
Hi weve.
I don't have the k2 arms with me...I got them shipped to my in-laws in the USA and will be picking them up latter this month.
The A1 have less weight, 48.5 gr, with it's weight more in the middle. The K2 weigh 54 gr and has the weight more at the tips.
I don't know about B1 arms.
The K profile will be more agressive in upshifts but the A will be better for back shifts...that's how I see it anyway?
Life for me on my snowmobiles is 99.9% regular riding with maybe one race against a buddy per year.
Rene
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