Mutch ado about clutching

[TheyCallMeSal]

So I at first chalked my having to change my clutch pack out at 6900 miles to a fluke, since I had found other rushmore riders experiencing premature clutch failure as well. Since doing this on Friday though, my friends all seem to have their own theories on how I brought this on myself, and so I'd love to get the thoughts from some of the more experienced riders here, as to whether or not this was my fault...

First and foremost, I definitely don't ride the clutch, so that's not a factor at play here.

Now for the first opinion, the mechanic (indy) who replaced my clutch pack: He showed me my plates and they were all solid black. He said it should have lasted around 50k miles and there should have been no way I could have caused this sort of failure if I tried.

Next opinion, friend #1: Says he notices I short shift a lot and that probably did it. I do tend to short shift, if lets say I'm getting on a freeway and want to quickly get my feet on the highway pegs. As I go up the on-ramp I'll up-shift at 2500 rpms like you would when breaking in the engine, in order to get to 6th faster so I can get my feet on the pegs as soon as I'm on the freeway. Maybe that's not a great habit, but I don't see how that shaves 44,000 miles off the life of the clutch plates.

Friend opinion #2: While talking to a group of friends about this, I mention the only thing I do that I think might adversely effect clutch life, is engine break. I engine break through all gears down to 2nd when I can. For example, if I'm coming up on a light turning yellow a few hundred yards away I get off the throttle, when the engine hits 2k rpm I pull the clutch in, drop down a gear, and blip the throttle just before releasing the clutch lever (to rev match). The engine goes up to about 3k rpm, and when it hits 2k rpm I repeat, until I hit 2nd gear, at which point I slide into neutral and use the brake to complete the stop. This friend says "well that's it!", and claims you should only down shift to 4th gear at most, and just pull the clutch lever, and click down to neutral while braking to a stop.

Again, I don't see how either two practices would cut the life of the clutch so severely. I do ride the bike aggressively, but my line of thinking is along with the mechanic in that even aggressive riding/shifting shouldn't result in a clutch failing at 6900 miles. I would totally buy the theory of my clutch failing at 30k instead of 50k because of me downshifting, but this just seems a bit much. Alas, I refer to your experience and opinions on the matter. Does short shifting drastically shave 10's of thousands of miles off of clutch life? Does engine breaking?

 

[BluesBelly]

I have ridden many many miles with riders of all styles and have never seen a clutch fail under normal riding conditions. My best friend, king of short shifters, has 90k on his original Bagger clutch and it still is good to go. I am the guy who down shifts matching revs w speed using the engine as a break and have never had issue in all my years and bikes. I also know guys that love to do burnouts and they have no issue.
I doubt that your riding style is to blame but rather look toward a defective part. One possible theory is that the original clutch spring is defective in that it does not produce adequate pressure on the plates and they slip as you ride.

 

[Happy Glider]

So I at first chalked my having to change my clutch pack out at 6900 miles to a fluke, since I had found other rushmore riders experiencing premature clutch failure as well. Since doing this on Friday though, my friends all seem to have their own theories on how I brought this on myself, and so I'd love to get the thoughts from some of the more experienced riders here, as to whether or not this was my fault...

First and foremost, I definitely don't ride the clutch, so that's not a factor at play here.

Now for the first opinion, the mechanic (indy) who replaced my clutch pack: He showed me my plates and they were all solid black. He said it should have lasted around 50k miles and there should have been no way I could have caused this sort of failure if I tried.

Next opinion, friend #1: Says he notices I short shift a lot and that probably did it. I do tend to short shift, if lets say I'm getting on a freeway and want to quickly get my feet on the highway pegs. As I go up the on-ramp I'll up-shift at 2500 rpms like you would when breaking in the engine, in order to get to 6th faster so I can get my feet on the pegs as soon as I'm on the freeway. Maybe that's not a great habit, but I don't see how that shaves 44,000 miles off the life of the clutch plates.

Friend opinion #2: While talking to a group of friends about this, I mention the only thing I do that I think might adversely effect clutch life, is engine break. I engine break through all gears down to 2nd when I can. For example, if I'm coming up on a light turning yellow a few hundred yards away I get off the throttle, when the engine hits 2k rpm I pull the clutch in, drop down a gear, and blip the throttle just before releasing the clutch lever (to rev match). The engine goes up to about 3k rpm, and when it hits 2k rpm I repeat, until I hit 2nd gear, at which point I slide into neutral and use the brake to complete the stop. This friend says "well that's it!", and claims you should only down shift to 4th gear at most, and just pull the clutch lever, and click down to neutral while braking to a stop.

Again, I don't see how either two practices would cut the life of the clutch so severely. I do ride the bike aggressively, but my line of thinking is along with the mechanic in that even aggressive riding/shifting shouldn't result in a clutch failing at 6900 miles. I would totally buy the theory of my clutch failing at 30k instead of 50k because of me downshifting, but this just seems a bit much. Alas, I refer to your experience and opinions on the matter. Does short shifting drastically shave 10's of thousands of miles off of clutch life? Does engine breaking?

No offense to your friends but none of what you describe should cause clutch failure that early. And…I certainly wouldn't describe your riding as aggressive. When they/you changed the clutch did you inspect fluid for anything abnormal?


Sent from my iPhone using Tapatalk

 

[TheyCallMeSal]

No offense to your friends but none of what you describe should cause clutch failure that early. And…I certainly wouldn't describe your riding as aggressive. When they/you changed the clutch did you inspect fluid for anything abnormal?

No offense taken! I thought they were full of it, which is why I wanted some opinions from here. Now, when the fluid was drained it was black, and the tech said it looked thin but that could be because it was synthetic. It was in fact synthetic: it was Mobil 1 Racing 4T 10w40 motorcycle oil. After doing as much due diligence as I could on oils to use on the bike when doing my first (1k) service, I went with this in the primary over the Mobil 1 V-Twin 20w50 I use in the engine, because I had read multiple people mention this slightly thinner fluid was better at penetrating the tight spacing between plates on Harley's 6-speed clutches. The fluid did come out black, but the tech didn't seem to think that was the cause of the premature failure, as there are plenty of guys running 10w40 in their primaries. Although, to be safe, he used the Bel-Ray V-Twin Primary Fluid he ordinarily uses when he buttoned up the primary after replacing the clutch. And noted that although Harley calls for changing primary fluid every 10k miles, he recommends doing it every 5k along with the engine oil.

Edit: Mobil themselves in fact suggests the use of their 10w40 Racing 4T fluid in Harley primaries on their website. So I'm pretty confident it wasn't a fluid issue. (And the fluid level was measured as being the exact amount called for in the service manual)

 

[EvilTwin]

I don't think your ridding style hurt the clutches , mine takes a lot more abuse than what you are doing and if the oil said it was ok for a wet clutch , I would think it was a defective clutch pack. I do run primary oil in the primary. I know most v-twin oil says its ok to run but I would much rather run the fluids that were designed for each application . I like the Klotz fluids. I noticed my clutches bite better than when I was running motor oil in the primary..

 

[y22c]

No offense taken! I thought they were full of it, which is why I wanted some opinions from here. Now, when the fluid was drained it was black, and the tech said it looked thin but that could be because it was synthetic. It was in fact synthetic: it was Mobil 1 Racing 4T 10w40 motorcycle oil.

The oil wasn't thin because it was a synthetic it was thinner compared to a 20w50 because you are using a 10w40.

Base stocks had nothing to do with it.

Ken

 

[Klmack]

My first set of plates failed at 3,000 miles- while going up a hill in San Francisco with a passenger. I had HD replace with the Screamin Eagle (SE) plates. Second set was replaced at 5,000 miles- I was hearing a squeak/rub/grind while taking off from a stop light when bike was cold. HD replaced the clutch basket and bearing- bearing had come loose from the basket. I had them replace the SE plates with OEM plates- they were either going to put back in the used SE plates or new OEM, so I went with the new. I was telling this to an HD engine builder and he suggested I replace the OEM diaphragm spring with an HD Screamin Eagle spring, as the OEM spring does not cause enough pressure and promotes slipping. He said that once I do this, I will never again have slip problems. I replaced the OEM with the SE at 10,494 miles and am now at 15,106, with no problems at all. It's a little heavier pull, and I do feel it in my hand after rides with heavy twisties, but I now have clutch confidence. Here are the parts used:
* HD SE Clutch Spring: PN37951-98, $34.12
* James Primary Gasket: PN 264035, for HD PN 34901-07, $16.38 at Dennis Kirk
* Red Line V-Twin Primary Fluid- 36 ounces used, $12.95 at Cycle Gear
Make sure you torque the primary bolts to spec and in the order listed so you don’t have any leaks. I will be changing out the Primary fluid after my trip to Hollister this weekend. It's full synthetic, but I stick with the maintenance schedule when it comes to fluid changes. Hope this helps

 

[TheyCallMeSal]

Awesome info, thanks for that!

I went to an indy mechanic and had them put in an aftermarket clutch pack and spring (I can't remember the brand at the moment), after hearing other have had similar premature failure with the OEM setup. I'm hoping that this does the trick (the gears do tend to bite in a way they never did before - indicating the stock spring certainly did promote slipping), but I appreciate you sharing this info as if I encounter more problems I'll definitely be giving those items a try!

Edit: I see you're going to Hollister Rally! I'm thinking about trying to go up from SoCal and come back the same day (Saturday) - I just posted about it in the 'Pacific' rides section. Hopefully I'll see you there!