Clutch marks

[TD Max]

Took a peek at my clutches yesterday. I have had difficulty crossing 80mph and have pretty low RPMs. I was expecting to see some black at engagement maybe see evidence of how high the belt was riding in the sheaves, but not dual lines. The upper seems to be representative of my top speed/shift, but what is the lower line?

The sled has just over 200 miles on it now. Ulmer machined primary and secondary. Ulmer clutch kit.

Engagement is quite notchy. It wants to hang then jump in and grab. Very difficult to move short distances like trailer loading. On the snow, It hits really hard out of the hole, track hooks awesome but then seems to drop RPM possibly 7800- 8,000 and then builds slowly to 8400-8500 range. Hard to watch the tach and try to control a machine that is not steering due to ski carry. Sounds similar to the discussion about clutching RPM after studding.

Belt dust is there, I get it on my fingers, but I'd say minimal. Nothing has been cleaned prior to taking this picture.

While changing weight setup I left the clutch bolt in and removed the 6 screws that attach to the moveable sheave. I noticed that the moveable sheave slides, but has plenty of resistance. I did not test the cover bushing drag, but I suppose I should?

Do I live with/ignore the drag of the bushings and let them wear in or do I try to do something about it?

 

[Studroes144]

Is this with the stock belt or 8dn belt?

 

[TD Max]

8DN

 

[Studroes144]

Secondary wound too tight? That sounds very possible to me. If your secondary spring is too right then it'll stop the secondary from shifting while the primary is still trying to shift meaning it'll slip the belt giving you burn marks and/or dust. Are u at 6-2 on secondary?

 

[TD Max]

Yes 6-2 on Ulmer setup

 

[Studroes144]

I ran 6-2 with the red spring and got a lot of dust and lower speeds and jerky engagement, I think it needs to be loosened up to like 6-1 or 3-3. Just for a test if u wanna try it go do a wot run as is and then put your stock secondary spring back in at 6-2 and see if there's any difference. Either way your rpm is low

 

[NOS-PRO]

I had 2 lines this past weekend....but it was because the little rubber pad that is in-between the fuel tank and the clutch guard decided to come loose, stick to the secondary sheave and make a sound like cards in my bicycle wheel when I was younger.

TD has a couple things going on and his primary not being able to move freely is not helping his engagement. Also might be binding and slipping the belt in these areas??? Plus belt dust with the 8DN....something not right

 

[subaru2006]

I would suggest cleaning the clutches. That sounds like biggest problem. Clean them and see if it goes away. The primary should be able to move in and out freely/easy. Let us know if that works.

Subaru2006

 

[Studroes144]

Definitely needs clutches cleaned, but there's a reason why that happened. That's what needs to be solved

 

[NOS-PRO]

Definitely needs clutches cleaned, but there's a reason why that happened. That's what needs to be solved

Agreed

 

[Studroes144]

First things first, if it's ulmers kit I'd call him, not only will he help u with getting it right but he will want to know what's going on for the future. I know cannondale has done a fair amount of on snow testing with that red spring recently and in talking to him he confirmed that loosening the secondary spring wrap cured the belt dust issue. If I remember correctly he ran his at 2-3. You'd want to confirm that with him and ask Allen about it, but from what I saw with mine I bet your secondary is wrapped too tight

 

[titanrcr]

I lot of what you describe sounds like loose belt deflection especially with the jerky low speed and engagement issues. Your running an 8DN so I would expect to see that belt running higher than normal on the secondary. I personally set my deflection a second time after a belt has broken in a bit, after a few hundred miles it needs it. I set deflection on the tight side so that the track will just creep when the sled is idling and track lifted off the ground. I would blow out the primary, clean the faces reset deflection and give it another go. Seems odd that it's making black marks halfway up the primary face?

 

[TD Max]

Clutches are pretty darn clean, but I cleaned a bit anyhow.

So how loose should the moving sheave be? If I were to lay the clutch down flat with no spring it most definitely would hang and require a steady push to get it to fall. I'm going to put the cover back on w/o the spring and see how it slides when assembled.

Nos,

The rubber shim was still in place not getting into the clutch.

 

[titanrcr]

That primary should be totally free, zero force to move the face with no spring.

 

[Studroes144]

I lot of what you describe sounds like loose belt deflection especially with the jerky low speed and engagement issues. Your running an 8DN so I would expect to see that belt running higher than normal on the secondary. I personally set my deflection a second time after a belt has broken in a bit, after a few hundred miles it needs it. I set deflection on the tight side so that the track will just creep when the sled is idling and track lifted off the ground. I would blow out the primary, clean the faces reset deflection and give it another go. Seems odd that it's making black marks halfway up the primary face?

Burn marks half way could likely be from that spring being too tight and not allowing the secondary to shift while the primary is still shifting, belt becomes the weakest link and is slipping, just my opinion but that's what happened with mine