need help Rotax muffler spring lugs - distance?

[Marty_d]

Hi all,

 

Can anyone tell me how far apart the spring lugs should be when the muffler pipes are in position? Or failing that, how much should the springs be stretched?

 

I'm taking the stainless steel lugs up to the welder tomorrow, but it'll probably be a while before he gets around to it anyway.

 

 

Thanks!

 

Marty

[skippydiesel]

I am sure someone will have definitive an swear for you my contribution is - make sure the "lugs" line up. My, off the shelf, system seems to have the "lugs" almost randomly situated, making for difficult assembly/disassembly and makes me think that the forces applied are not symmetric.

[Marty_d]

Thanks skippy, everything is held on a jig while he welds it, so if he does the lugs after welding the bends in the pipes there's no excuse for it NOT to line up...

[Downunder]

I'm not able to measure mine at the moment.

I'm guessing you want about 5mm spring stretch seated and will probably pull twice that to get them on.

[IBob]

Can't help with that, Marty: the Sav comes with it's own pipes/muffler/springs and I'd be surprised if they are the same.

[IBob]

....that is, the pipes and muffler are quite different, I doubt the springs are the same...........

[Blueadventures]

Marty you can also check some images and note the gap between the coils and you can measure your coil guage of wire. THis wioll allow determination of spacing. Also decide were you want the lug loops as you may have access requirements to fit and remove the springs. So a little thought as to thier location may be nice later on when servicing, as you will need to remove and Kopa Kote evey second oil change. Cheers

[turboplanner]

You can scale up from this at 1:10

 

I broke quite a few springs and found that less tension was batter than more, but mine were running very hot at around 10,000 rpm.

Edited August 19, 2020 by turboplanner

[Kiwi]

From rotaxowners..

 

https://www.rotax-owner.com/en/912-914-technical-questions/5448-exhaust-springs-912-uls

[Marty_d]

Marty you can also check some images and note the gap between the coils and you can measure your coil guage of wire. THis wioll allow determination of spacing. Also decide were you want the lug loops as you may have access requirements to fit and remove the springs. So a little thought as to thier location may be nice later on when servicing, as you will need to remove and Kopa Kote evey second oil change. Cheers

Thanks - the position of the lugs is set by the muffler which already has lugs welded on the ball holder stub thingies.

 

So - there's no standard spacing or stretch for the standard Rotax muffler springs?

[Blueadventures]

Thanks - the position of the lugs is set by the muffler which already has lugs welded on the ball holder stub thingies.

 

So - there's no standard spacing or stretch for the standard Rotax muffler springs?

There would be, I have at CKT exhaust so cannot help with a measurement. Mark Kyles mate Danny may have some info as he makes bits for rotax engine mufflers, he will be in the Balance master thread as he sells them. Cheers

[DeanT]

Marty

This is my first post so I hope I get it right and that it helps you.

The transversely mounted muffler on my Rans S7 has three springs each side and the loops that hold them vary in distance from 70 mm to 90 mm apart.

They have been there for 20 years without any problems.

Dean