18 Clutch Specs

Rotax_Kid · Jul 14, 2017

2018 Calibration Changes have been released.

Here's a link to the bulletin:

http://cdnmedia.endeavorsuite.com/i...21c-0564a405117f/2018 High Altitude Specs.pdf

Attached is a spreadsheet I maintain for some clutch calcs that summerizes the year over changes. Apologies for the quality - I wanted to post a PDF but the server is complaining about the size...hopefully the JPG is readable. If not let me know.

ferniesnow · Jul 14, 2017

Is this more readable.......no it wasn't. Carry on.

Rotax_Kid · Jul 14, 2017

ferniesnow said:
Is this more readable.......no it wasn't. Carry on.

You just get whittier with age don't you? haha Let me try this again at a A4 size...woul dbe much easier to read on 11x17 but site won't let me upload even a Legal sized PDF

TylerG · Jul 14, 2017

Rotax_Kid said:
You just get whittier with age don't you? haha Let me try this again at a A4 size...woul dbe much easier to read on 11x17 but site won't let me upload even a Legal sized PDF

I changed some settings in the back end, see if you can get the larger one to upload again

Rotax_Kid · Jul 14, 2017

TylerG said:
I changed some settings in the back end, see if you can get the larger one to upload again

Thanks Tyler but no dice..here's the error I get...

Clutch Tuning Workbook Excerpt 14 Jul 17.pdf - The Dimension limits for this filetype are 1000 x 1000. We were unable to resize your file so you will need to do so manually and upload it again. Your file is currently 1224 x 792.

TylerG · Jul 14, 2017

Rotax_Kid said:
Thanks Tyler but no dice..here's the error I get...

Clutch Tuning Workbook Excerpt 14 Jul 17.pdf - The Dimension limits for this filetype are 1000 x 1000. We were unable to resize your file so you will need to do so manually and upload it again. Your file is currently 1224 x 792.

adjusted some more

ferniesnow · Jul 14, 2017

Rotax_Kid said:
You just get whittier with age don't you? haha Let me try this again at a A4 size...woul dbe much easier to read on 11x17 but site won't let me upload even a Legal sized PDF

Hahaha..........I tried to do some adjusting in iPhoto/Preview but it was blurry, so I deleted it.

I tried to help to no avail.

Rotax_Kid · Jul 14, 2017

TylerG said:
adjusted some more

Thanks for the magic! Fixed first post

Rotax_Kid · Jul 14, 2017

ferniesnow said:
Hahaha..........I tried to do some adjusting in iPhoto/Preview but it was blurry, so I deleted it.

I tried to help to no avail.

So iFix didn't work?

Bnorth · Jul 14, 2017

Not sure on the ramp but the rest of the differences are pretty minor. Little more finish force in the primary, still the crappy blue secondary spring, and in typical skidoo fashion have geared it down to make up for inadequate clutching.

Edit: there's an error in your sheet for the 4-8k on the 175 .076 should be .066 in the grams/lbs column.

Edit Edit: I is an idgit.

Rotax_Kid · Jul 14, 2017

Bnorth said:
Not sure on the ramp but the rest of the differences are pretty minor. Little more finish force in the primary, still the crappy blue secondary spring, and in typical skidoo fashion have geared it down to make up for inadequate clutching.

Edit: there's an error in your sheet for the 4-8k on the 175 .076 should be .066 in the grams/lbs column.

Agree with you...curious on new ramp profiles.

I use the grams/lbs column as a check - it's the pivot weight divided by the total primary spring force. In this case it would have been 15.2g (33mm pivot weight) /200lbs (G/W 200/400 spring) - 15.2g/200lbs = 0.076. Doesn't mean a thing...just a ratio check to look for a trend.

Deano670 · Jul 18, 2017

Bnorth nailed it. Low gearing= Band aid for poor clutching. Problem is the gearing is already so low its IMO the root cause of alot of belt blowing problems. Or the fact the front engine mount flops around like a fish out of water. Either way we made fixy fixy lol.

Deano

Mad Motorsports

snochuk · Jul 18, 2017

Deano670 said:
Bnorth nailed it. Low gearing= Band aid for poor clutching. Problem is the gearing is already so low its IMO the root cause of alot of belt blowing problems. Or the fact the front engine mount flops around like a fish out of water. Either way we made fixy fixy lol.

Deano

Mad Motorsports

So did you make a stiffer mount?
What fixy fixy did you make as this appears to be beyond the realm f BRP.

Deano670 · Aug 1, 2017

No I made some very simple shim kits ranging from .060"-.090" to take out the excess clearance between the rubber mount and the aluminum casting. This way the engine is at least tight before your on the throttle. The way they are stock the engine moves that .060"-.090" before the rubber is even against the aluminum casting.

Deano

Mad Motorsports

Deano670 · Aug 2, 2017

Near impossible to keep a belt on anything when your shaft centre to centre distance is constantly changing, no matter what clutches are on the machine.

Deano

Mad Motorsports

jpmez69 · Aug 2, 2017

New engine mounts on 2018 models.

snochuk · Aug 2, 2017

jpmez69 said:
New engine mounts on 2018 models.

Read one post above yours......don't get to horny on the changes when the real issues not addressed, just bandaided.
Wobble wobble wobble

drew562 · Aug 4, 2017

snochuk said:
Read one post above yours......don't get to horny on the changes when the real issues not addressed, just bandaided.
Wobble wobble wobble

I'm back on a cat for the first time since 2012. The 2018 mountain cat is the sled to buy. $3000 cheaper and one belt for a spare. If I had a new 850 I would need a belt every 3 days.

Caper11 · Aug 4, 2017

Interesting pic of the jackshaft, either doo forgot about the secondary or maybe the secondary is removable finally.

Daag44 · Aug 5, 2017

Hope it's removable.

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