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Post by admin on Jan 16, 2012 22:03:42 GMT -5
I have a slight issue with my 69' Mark III where the primary drive clutch on the engine does not always disengage when coming to a stop, causing an engine stall when I hit the brake. My idle is not set too high!  From what I have read, the cause might be a weak spring which are available NOS here and there. I have also read where an incorrect belt size can cause this problem. I am toying with the idea of installing a Comet 94C clutch someday. I thought I would post a few links for us. Here's a link to cross our Scorpion sled models to the Comet clutch models, www.psep.biz/store/scorpion_snowmobile_clutch_-_complete.htmHere's one link where I found new Comet clutches. I would probably buy a used one somewhere, www.mfgsupply.com/snowmobile/snowclutch/snowcomet/snowcomet94c.htmlFor example, I think my 69 Mark III would use the Comet CO211493 if my 370 Sachs engine shaft is the same size as the 280cc single Sachs listed (30mm). Does anyone know if the crankshaft end for the clutch is the same for all the Scorpion Sachs singles? Does anyone have any experience with their original clutch not disengaging and the fix is the spring or? Has anyone ever swapped out the OEM clutch for one of these Comet 94C units and how would you describe the improvement in performance? Feel free to share any feedback you have, and thanks for your contributions! |
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Post by pararailer on Jan 16, 2012 22:48:04 GMT -5
scorpion clutches have rollers in them that often wear flat spots in them. that could be part of the problem.
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Post by ddub on Jan 16, 2012 23:39:40 GMT -5
Pararailer is correct. Another thing to look for is that the clutch is aligned and the proper distance. along with that it is the correct clutch. Check with Jack P or Chip, they should have those rollers. That was a VERY common problem from what my dad told me. They were flat on the 69 and he said that he had replaced them several times previous. A 94C would be a better clutch from my limited knowledge from heresay, BUT does that 370 need a better clutch?  If you want, I can check my catalog as to the comet for the 370, but the crankshaft SHOULD be the same I THINK! |
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Post by obj1 on Jan 17, 2012 18:51:23 GMT -5
For your 370 single just get a clutch off of a newer super stinger. It'l work fine. We run 94c's on our 400cc race sleds and 102c's on our whips and tk's. On our 3 70 stinger 340ss sleds we have the super stinger type clutches. A 102 will require clutch guard modification.
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Post by ddub on Jan 17, 2012 19:07:39 GMT -5
obj1
So from what you are saying the clutches from the newer twins will fit the Sachs? INTERESTING!
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Post by obj1 on Jan 17, 2012 20:22:39 GMT -5
Yep, check the taper. If the sachs has the 25mm taper crank, a bushing is available to go from 30mm down to 25mm. Or, leave the fixed sheave in place and just install moveable sheave and cover off of a super stinger. The difference is the newer clutches has a snap ring after the bearing, the old "L" arm clutch did not. All of our singles have newer clutches on them. If you look in the parts books you will see a few different #'s for the fixed sheaves but, if i remember right other than the taper, the ccw's might of been different off set for clearence on the cyl head. not sure though, i'd have to check my stuff. I know we have a clearence issue on the 340ss motors cuz the cylinder head sticks out some. set alignment off set with straight edge at 3/8" and center to center at 10 1/2" or slightly less.
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Post by admin on Jan 17, 2012 20:53:19 GMT -5
Thanks for the excellent info! I am thinking the 370 single Sachs has the 30mm shaft since the 277cc and 280cc both use this Comet Duster 94C clutch for 30mm shafts, www.mfgsupply.com/211493a.html |
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Post by admin on Jan 17, 2012 21:01:28 GMT -5
scorpion clutches have rollers in them that often wear flat spots in them. that could be part of the problem. This information is going to help a lot of people in the future too. Thanks! |
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Post by admin on Jan 17, 2012 21:02:38 GMT -5
Check with Jack P or Chip, they should have those rollers. That was a VERY common problem from what my dad told me. They were flat on the 69 and he said that he had replaced them several times previous. A 94C would be a better clutch from my limited knowledge from heresay, BUT does that 370 need a better clutch? Great question! ;D |
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Post by admin on Jan 17, 2012 21:07:36 GMT -5
Pararailer is correct. Check with Jack P or Chip, they should have those rollers. That was a VERY common problem from what my dad told me. They were flat on the 69 and he said that he had replaced them several times previous. In all my hours of scouring the net, I never saw this issue pointed out before this thread. A weak spring was mentioned a few times. Then again, there is very limited info posted on the internet about the fine arts of Scorpion loving - LOL |
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Post by admin on Jan 17, 2012 21:14:09 GMT -5
For your 370 single just get a clutch off of a newer super stinger. It'l work fine. We run 94c's on our 400cc race sleds and 102c's on our whips and tk's. On our 3 70 stinger 340ss sleds we have the super stinger type clutches. A 102 will require clutch guard modification. obj1, can you give me a year range of Super Stinger that would have this good clutch on it for 30mm shaft? I find it interesting that with all the resources and experience you have, you are using the Super Stinger clutch on your 340SS sleds. I think what this tells me is, that is a very good clutch! Is it accurate to say, I don't really need a Comet clutch because the Super Stinger model will give me all the performance I will ever need at a more reasonable cost? I am just driving my Marks recreationally, no racing. |
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Post by admin on Jan 17, 2012 22:03:37 GMT -5
set alignment off set with straight edge at 3/8" and center to center at 10 1/2" or slightly less. obj1, can you go into a little more detail about your clutch alignment procedure above for us slower inexperienced people? |
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Post by obj1 on Jan 17, 2012 22:36:00 GMT -5
Find a clutch off a 73-74-75 sled. It will have #042911 on the back or fixed sheave. check rollers, must not have flat spots. clean it good, make sure it works smooth. The drive clutch and driven clutch must be off set 3/8" of a inch. Check this with a straight edge on the back side of sheaves. last. distance from center of crank to center of jack shaft is 10 1/2" We have tried different clutches on our race singles. We could never get the right weights and springs to have a hole shot and "pull" all the way down the track. The scorpion clutch is a little slow off the line due to low engagement but they pull all the way down track. At mid track we start pulling away.
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Post by mooreperformance on Jan 18, 2012 12:39:33 GMT -5
I may be wrong here but you should be able to leave the original fixed clutch sheave on the engine and just install a new movable sheave (with new style H-arm weights). Then you won't have to worry about what diameter (25-30MM) the crank is!
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Post by obj1 on Jan 18, 2012 13:11:24 GMT -5
Your right. I said just that up a few messages.
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krainz
L1 Scorpion - The Great Snowmobile
Posts: 7
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Post by krainz on Jan 19, 2012 0:27:30 GMT -5
Agreed, that simplest fix is the flat spots on the orignial nylon rollers. There was an after market 'reinforced' roller that held up better. We found the lubrication of the clutch spline to be critical. At that time, Ski Do had a clutch lube that was a synthetic plastic type that was extremely low temp that would not fly off the spindle.
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Post by admin on Feb 3, 2012 21:40:08 GMT -5
I'm just getting around to taking my clutch apart for inspection on the 1969 Mark III 370 Sachs single. The big bolt holding the clutch on is larger than any socket I have, so I'll have to buy a socket. What size is this bolt and do I just hit it with an air impact wrench in the normal counterclockwise rotation to loosen it?  |
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Post by admin on Feb 3, 2012 21:54:16 GMT -5
Find a clutch off a 73-74-75 sled. It will have #042911 on the back or fixed sheave. check rollers, must not have flat spots. clean it good, make sure it works smooth. The drive clutch and driven clutch must be off set 3/8" of a inch. Check this with a straight edge on the back side of sheaves. last. distance from center of crank to center of jack shaft is 10 1/2" We have tried different clutches on our race singles. We could never get the right weights and springs to have a hole shot and "pull" all the way down the track. The scorpion clutch is a little slow off the line due to low engagement but they pull all the way down track. At mid track we start pulling away. obj1, How would this clutch from a 1975 Whip 440 work on my Sachs 370 single?  |
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Post by admin on Feb 4, 2012 9:02:08 GMT -5
Find a clutch off a 73-74-75 sled. It will have #042911 on the back or fixed sheave. check rollers, must not have flat spots. clean it good, make sure it works smooth. The drive clutch and driven clutch must be off set 3/8" of a inch. Check this with a straight edge on the back side of sheaves. last. distance from center of crank to center of jack shaft is 10 1/2" We have tried different clutches on our race singles. We could never get the right weights and springs to have a hole shot and "pull" all the way down the track. The scorpion clutch is a little slow off the line due to low engagement but they pull all the way down track. At mid track we start pulling away. I have not touched the alignment yet. How does it look here by eye?   |
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Post by admin on Feb 4, 2012 10:11:49 GMT -5
Unrelated to my little clutch project, I found this clutch on the internet. It is listed as a DRUMMOND POWERBLOC CLUTCH for SACHS SA 290 SMALL TAPER CRANK Does anyone have any knowledge of this type of clutch?    |
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