But you know... some guy mentioned he would ride 300 miles a day and use the clutch only to get gas at 150 miles. Myself, riding in the city most of the time, I'll probably use the clutch 500 times in that same 300 miles. Is he better at using the clutch than me? I'm pretty sure mine will fail way before his...

 

Yes, I've done both. I can do a 400 mile road trip and run through the gears maybe once every 150 miles for small Ohio towns.

Usually, it's a lot of city traffic and work commuting. I will run the clutch 10x as much in the same 400 miles in those conditions.

Like I said before, it is a fatigue failure. It's literally the number of times you pull the clutch. Not how many miles, because the action that stresses those rivets is not dependent on distance travelled.

I'm sure compression rivets make sense from a design standpoint in HD's spec world (there are a lot of constraints on us engineers for cost and manufacturing), but in this case it just doesn't hold up.

I also think that the transmission redesign in '04 has something to do with it (my current working theory is related to the switch from opposed Timken angular bearings to the antique plain rolling bearings on the crank pinion shaft). Not sure how yet, but I'm working on my theories. The '06+ bikes have more of a case being helical gearsets and all, but fitting that in to the '04 and '05 bikes still has me a little stumped.

 

That fits with my hypothesis, something with the rubbermount design may be a factor. The data supports you so far, versus the other theory. I think we can agree that DB's theory does not explain all the causes of failure. I'm thinking that even a 7% baseline is liberal for his theory of driver induced failures. Now we need to explain the other 26% of rubbermount failures.

Revised numbers: Rigid failure rate (40 responses): 7.5%, Rubbermount (109 responses): 33% Most rubbermount failures reported 10K to 30K miles. Still a significant difference IMO. I think the rigid number would drop if you have the same number of responses, just my theory.

http://xlforum.net/vbportal/forums/s...ing+plate+poll

Check the numbers and see what you think. Remember, rigids are old bikes now, several owners likely. Who knows the history.

Yes, you also you have another variable introduced with the helical gearset in '06. Another factor favoring something the factory changed has an effect.

Remember, you can NEVER prove a theory, only disprove it.

John

 

Agreed.

My current theory, obviously, favors the thrust loading of the helical gears. Only, this doesn't account for the '04 and '05 years where the spur gears were still in play. The engine castings and primary side crankshaft bearings were redesigned, so that could be a factor (my only major difference so far). The thrust loading is significantly worse with the roller bearings as compared to the angular bearings. The Twin Cams are evidence of this alone.

I'm working on getting info on the cases/transmission for the '04 redesign. It's just a tough point considering my company and HD have a lot of trade secrets and my work is not related to the drivetrain section.

Until then, it's all speculation based upon our experience and expertise. But when you factor in the transition from opposed Timken bearings to a single roller bearing and thrust washers, combined with the excess axial forces of a helical gearset on the main/countershaft (2nd-5th, 1st still spur) in the '06+ bikes, it doesn't look good.

The Twinkies went through a similar issue in '03+ bikes by moving away from the Timken angular bearings in the B engine. That is still an issue today.

I'm rambling now, but that is my opinion. I'm pretty sure it's related, but "how" I am not yet sure of.

 

I'm not an engineer, but I can do simple statistical analysis and see something sticks out like a sore thumb.

John

 

8 years old? Yep. Started out on dirt bikes.

Even with the amount of BS you talk about clutchs I personally refuse to talk bad about the service of another who has served. As a combat medic I know loss.

By the way, you do remember this little thing called leave right?

That doesn't mean I'm backing down about the clutch thing because you're totally off base. Nor does it mean that I don't think that you're a ********. Because you are. It just means that I respect the sacrifices. But you're still a ********.

 

Let's debate the gentleman on the facts, or at least some simple statistics. His theory has holes, debate that.

Name calling is kindergarten level. Especially on the internet. And unbecoming of a soldier, sailor, aviator, or Marine.

John

 

You dont have to back down on anything. Neither do I. The small, very small numbers online do not represent the even greater numbers who are not, and there is way more not than there is.

I am saying all the sporty owners I know who are mostly 04+ owners who all have more than 25K on the bike have not had an exploded clutch, and we dont expect any. They all dont explode, a theory was thrown out they do and I threw out a theory that the cause is abuse in one flavor or another.

Yall might scare someone off from getting one if they read that all the clutches explode. I am letting them know they do not. I am throwing it out there to them, not you few, that there are more who never have a problem than those few who do. Thats it.

 

I pulled my 04's clutch plates just over 30,000 miles, and the rivets were loose, but still there. The fiber plates were barely worn; the clutch had not been abused, not worn out. Brass is a damned weak metal in that application, but enough people get 50K plus to show that it sometimes works reasonably well. The "all over the map mileage" failure of these rivets makes me wonder if the manufacturing process is inconsistent in rivet installation. I don't see how different gears or bearings would make much difference; those plates are on a shaft in a basket, and the only real load I can envision is the grab when you engage the clutch and the plates lock together. One thing's for sure, it happens often enough with no obvious reason that I wouldn't take a chance with it; should I ever buy another one, I'd ditch that rivet mess real quick. As far as the lone opinion on rider ability, it would be next to impossible to prove it one way or the other, but short of just dumping the clutch repeatedly, I don't see how that's much of a factor.

For around $100, you can have a rivetless clutch, and nobody's admitted to having one of those disintegrate, so it's worth the piece of mind to me. Plus, as I found out when I pulled it, mine was going to fail. And it's easy enough you can give the next generation a little hands on training while you're at it....