Just having fun with this rat!

[13bodies]

A 72 cheetah chassis with a 72 rotax 335.

[Coondog]

ha cool a Doo CAT

how does the Rotax push it?

CD

[13bodies]

The rotax pushes it great, but I have some bugs to work out with the clutching ("shifting").
I'll keep tinkering with it!

[GNR]

WICKED SLED

[olyman]

That looks like a pretty cool setup. That's the perfect engine for that rig (maybe I'm a little biased lol). Looks like you did a good job on the exhaust! Watch out with that air filter on it though, you don't want it to ice up and cause a leaning effect.
What kind of tension is on the belt? If it's too tight (or misaligned) you won't get good shifting.

[13bodies]

Jan 14, 2012 20:37:18 GMT -5 olyman said:

That looks like a pretty cool setup. That's the perfect engine for that rig (maybe I'm a little biased lol). Looks like you did a good job on the exhaust! Watch out with that air filter on it though, you don't want it to ice up and cause a leaning effect.
What kind of tension is on the belt? If it's too tight (or misaligned) you won't get good shifting.

I endured a lot of pains to be sure the alignment is right, however I'm afraid you may be right about it being a touch too tight. It has amazing low end power, but it just won't upshift to get any top end speed out of it!
So you think that is caused by a belt that is too tight?

[icebooger]

looks good nice fit ,,,
I never tried a 335 rotax how many more hp compaired to the 247 cc rota 12hp i think?

[olyman]

Jan 14, 2012 21:23:07 GMT -5 13bodies said:

Jan 14, 2012 20:37:18 GMT -5 olyman said:

That looks like a pretty cool setup. That's the perfect engine for that rig (maybe I'm a little biased lol). Looks like you did a good job on the exhaust! Watch out with that air filter on it though, you don't want it to ice up and cause a leaning effect.
What kind of tension is on the belt? If it's too tight (or misaligned) you won't get good shifting.

I endured a lot of pains to be sure the alignment is right, however I'm afraid you may be right about it being a touch too tight. It has amazing low end power, but it just won't upshift to get any top end speed out of it!
So you think that is caused by a belt that is too tight?

Ya, when it's too tight it's just anxious to go. and you wont have enough belt left to make it pull up high in the primary. Then on slow down, it will be reluctant to go back up high on the secondary.
Something else to watch out for is spring tension. With an old ski doo you would want to have ~8lbs of spring tension on the secondary using the OEM drive clutch. SO if you had much too much spring tension in the secondary it will wanna rev up high and not really go fast.
I still think that you just need to have either a longer belt or bring your secondary closer to the motor. I know old doo's are easy to adjust that, but don't have much experience adjusting a cat chaincase. Surely not that hard.

Page 40 - 62 explains about as much as you'd wanna know about an old doo clutch system CLICK HERE for 72' shop manual PDF

Another thing that might mess you up is if the Rotax clutch is getting worn out or sticky. There are 4 kidney weights that push against the end of the shaft. If the shaft gets grooves worn in the end, or the weights get deformed then you will have poor action there. You will wanna make sure the weights move freely & also put a little bit of clutch lube on the shaft. This will help make it move in/out freely - double check with your hands that it will actually move (when the belt is out of the way).

[jiggyjoe]

looks sweet

what type of exhaust pipe did you use? customized?

From what sled?

[13bodies]

Jan 16, 2012 1:31:38 GMT -5 jiggyjoe said:

looks sweet

what type of exhaust pipe did you use? customized?

From what sled?

Here is a picture of the pipe before I fabricated it to fit. It was off a Polaris storm originally!