Baz's Drak.

[Buggybaz]

30mm 1.75:1 taper? Please explain?
If you mean 1.75:10 then that still does'nt match mine.
The small end start is 27mm diam on both tapers in pic.
At 1:10,it is 30mm diam at 30mm in from the front small end.
That works,as 1mm rise per 10 mm length-27+3=30
Mine is 27mm start also,but finishes at 31mm diam at 30mm in,mine has risen 4mm over 30mm dist.
So mine is more like 1.33:10 taper to finish with 31mm diam at 30 in..That make sense?
Where would I find some specs on the Rotax tapers?

[Ozpilot]

I thought one was 1:10 and the other was 1:7.5 (or 1:7 - can't remember).  And I can never remember which is which.  But looking at the measurements I took of mine a couple of days ago and Baz's measurements (which are the same) reminds me the new SkiDoo is 1:7.5 and the (majority of the) others is 1:10.

[Admin]

30mm 1.75:1 taper? Please explain?
If you mean 1.75:10 then that still does'nt match mine.
The small end start is 27mm diam on both tapers in pic.
At 1:10,it is 30mm diam at 30mm in from the front small end.
That works,as 1mm rise per 10 mm length-27+3=30
Mine is 27mm start also,but finishes at 31mm diam at 30mm in,mine has risen 4mm over 30mm dist.
So mine is more like 1.33:10 taper to finish with 31mm diam at 30 in..That make sense?
Where would I find some specs on the Rotax tapers?

Look for clutches comet etc, I am certain the crank is 1.75:1.. just as a cat is 10:1 shit sorry, 7.5:1 were the hell i got 1.75 i havent a clue, lol....

[Admin]

yup i am all messed up tonight lol, 1:10 and 1:7.5...

[Admin]

So 30mm 1:7.5 taper.... That is what your crank shaft is...

[Admin]

That is why i asked my original question, how do you cut a 1:10 taper to a 1:7.5, I can see doing it the other way...

[Ozpilot]

BTW Baz, you need to get (if you haven't already got) an Aaen Clutch Tuning book.  Keep an eye out for one on the web and when you're buying something from somebody that sells them, buy one and get it sent over.  I think I have a spare (they update them and the girl at Aaen threw one in when I was there getting some stuff) so if I can find it I'll send it when I next send something (but try to buy one in the mean time as I may take ages before I send anything!!!)

The taper details may be on an aftermarket clutch site (Comet etc) or a site where they sell different aftermarket clutches (Goodwin etc).  Otherwise that CD I sent you may have it in (most likely in the Race Manual section).

[Ozpilot]

[Ozpilot]

Well ... you could actually cut a 1:7.5 taper clutch to 1:10 but I think it would then slip on too far as you're cutting lots out near the outside.

[Admin]

I had someone draw the two angles together one day, cad in 2 different colors, cant remember who, but a 1:10 taper will fit a 1:7.5, it had about 5 mm contact area at the big end, and was to small at the small end... Ill see if i can find it and rethink your suggestions!!

[Admin]

ok try this out...

A 30mm base with a 1:7.5 taper at 30 mm length will be 22 mm

A 30 mm base with 1:10 taper at 30mm will length will be 24mm

thus making the 1:10 taper larger at the small end correct?

[Admin]

Now unless i am totally wrong, you could not machine the 1:10 female taper, to accept the 1:7.5 male, but you could do it if it was reversed, a 1:10 male into a 1:7.5 female...

[Admin]

Tapers.... Rick the red is 1:7.5 correct?

[Buggybaz]

EUREKA!
Finally you 2 have nutted it out,and it makes sense.
Small end starts at 27mm,1:7.5 taper will have 4mm rise over 30mm length in,so it's 31mm diam at that 30mm mark.
Now at 37.5mm in,it should rise 5mm & measure 32mm diam? Mine does.
So the RooTax then is a 32mm 1:7.5 Taper?

[Admin]

Depends on how deep the clutch actually goes on, Ski doo is 30mm 1:7.5,  Were do you come up with the 37.5mm, Maybe alain bored the cat clutch 2 32mm so he could get more of the taper to machine out of the clutch... with the larger base diameter he could have machined it some, but i am guessing it does not have full contact the whole way in....