Hot Spots on Bully First Night Out

[tx3587]

First night out with a new Bully, same setup as my other one and it made a horrible grinding noise and was super loud when engaging. Took it apart and here are pics of the pressure plate and floater, are the hot spots normal or do I need to get it resurfaced?

 

[CarlsonMotorsports]

"

First night out with a new Bully, same setup as my other one and it made a horrible grinding noise and was super loud when engaging. Took it apart and here are pics of the pressure plate and floater, are the hot spots normal or do I need to get it resurfaced?

New" as in brand new from Buller, or do you just mean freshly rebuilt?
The pressure plate looks as though it could have use a bit more break-in time on it while the floater looks well used and has been hand sanded at some point in its history. (which is why I question the "newness" of this clutch.)
It's also common for aftermarket (hard) friction discs to created hot spots like this while not wearing the steel at all. The higher ceramic content of the aftermarket discs makes them harder/tougher and they can take heat abuse better, but the rest of the clutch is still the same steel material and the heat abuse is taken out on those parts.
I don't know what noise it was making, but that may be attributed to air gap if this was a recently rebuilt clutch. Let us know what air gap it had and maybe that's a big part of the problem.


-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
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34 years of service to the karting industry ~ 1Cor 9:24
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bcarlson@CarlsonMotorsports.com

 

[JPMKarting]

A few things to check for:

-Lever movement - make sure the levers move freely in the activator plate
-Spline tolerance - make sure the pressure plate and floater are able to move freely up and down the teeth of the drive hub spline

These 2 issues are the number 1 reason you see hot spots in the wear of the plates. I have even had brand new ones from Buller that the tolerances were so tight, that the slightest bit of dirt or heat warpage caused the levers and plates to hang up.

 

[tx3587]

Thanks for the replies. The clutch was brand new, never run and bought from a very reputable dealer. This wear is only from attempting the break-in process on the stand, 3 laps on the track and running it on the stand again. Just trying to figure out if it should be resurfaced before I rebuild it?

 

[UAS Racer]

I would send it to Buller to see what went wrong. If the clutch was used in the Buller recommended application; it's highly unlikely it would have not performed as intended right out of the box.

 

[ColeAchey]

Looks like normal for a new out of the box Bully to me. I agree with both Brian and JP, either something is hung up or the air gap is a little tight or the springs need to be adjusted depending on the spring/weight combo and the engine it's bolted to.

 

[Colt sr]

In my past experiences with new clutches is that they are not setup properly right from the box. Unless this clutch was bought directly from a clutch builder it may not be set up properly for your weight or class.

 

[tx3587]

Update: Put it all back together, checked air gap and spring heights, ran it on the stand for break in and made a couple of loops around the parking lot with no issues or noises, so hopefully no issues in the future

 

[CarlsonMotorsports]

Update: Put it all back together, checked air gap and spring heights, ran it on the stand for break in and made a couple of loops around the parking lot with no issues or noises, so hopefully no issues in the future

Could have just been the floater hanging up on the splines of the drive hub. I've caught more than a couple that were tight over the years. Glad you got it lined out.