Grooves in Primary Clutch Sheaves?

[burg226]

Just doing some periodic maintenance over the past couple weeks in anticipation for the late start to the season and I noticed that the primary clutch faces have developed (or have had all along) grooves in them. They appear to be at bottom of the clutches and on both sides.

How will this affect the engagement, etc? Is this normal (don't think so) and how can this be repaired?

Is it as simple as taking a file or some sandpaper to it? Has anyone had success with repairing them this way?

Sled is a 2008 Apex LTX with 20,000km.

Your thoughts, experience and input would be most appreciated!

 

[shagman]

Run it. I wouldnt worry about it that low in the clutch. I have seen this many times.

 

[sgauthier]

wouldn't worry about it. i'd be more concern if there were fatigue cracks down there but by the pics you're good.

 

[YAttak07]

I have the same groves which developed very early on.....believe it is caused by the very hard yamaha belts. they are much harder compared to aftermarket ones.

 

[4Fighter]

Are these the grooves that some people have "cut-down" so the clutch can close more to gain a little more Top-end? At 2500 miles my new clutch has the same thing.

 

[burg226]

Are these the grooves that some people have "cut-down" so the clutch can close more to gain a little more Top-end? At 2500 miles my new clutch has the same thing.

No, the reason these grooves appear this low in the clutch as per Schmidt Bros Motorsports (The company that does the overdrive machining to the clutch faces), is because of late engagement. They offer a "Comfort Spring" that will lower clutch engagement and reduce the hard impact on the clutch faces. Not sure if I'm sold on doing all of this yet. Might just leave the clutches for the season and think about doing it in the off season if I start blowing belts or losing performance.

Would these grooves affect or destroy my belt? Anyone run for a long time with these grooves?

 

[sgauthier]

not sure why it would effect your belt, it's only there at idle

 

[thor452]

I got the same Grooves in my primary they are slowly getting worse thet is where the clutch first impacts the belt mine are alott worse then yours I would not put much worry into it. I plan to look into it in the spring for mine but from how yours loooks VS how mine looks you have a full season to get to the point mine are at at least. but if you find a solution please post.

 

[4Fighter]

No, the reason these grooves appear this low in the clutch as per Schmidt Bros Motorsports (The company that does the overdrive machining to the clutch faces), is because of late engagement. They offer a "Comfort Spring" that will lower clutch engagement and reduce the hard impact on the clutch faces. Not sure if I'm sold on doing all of this yet. Might just leave the clutches for the season and think about doing it in the off season if I start blowing belts or losing performance.

Would these grooves affect or destroy my belt? Anyone run for a long time with these grooves?

Yes, that makes sense. I put my Attak spring in the used Apex clutch I recently acquired. I had 11K on the last clutch in my Attak and it NEVER gave me a problem. I change the spring every other season though.

 

[Sasquatch]

Belt wear!

 

[burg226]

Belt wear!

???

 

[Sasquatch]

???

The Yamaha 8DN belt wears the clutches. ie Belt wear!

 

[87gtNOS]

Belt wear!

exactly....hard belts do this.

Same thing was a big problem about 15 yrs ago when GATES first entered the market with their 'extreme' belt....it was so hard it was putting groves in SkiDoo clutches very quickly!!

 

[Sasquatch]

Yep since 2003 at least, My Warrior has 18,000 miles with the 8DN, clutches have grooves but everything works normal. My Apex has 7,000 but I don't notice the grooves so much on it yet.

 

[Irv]

I also have the same grooves in mine and may switch to an Ultimax, or whatever else people have used and have had good luck with?