What difference does it make? (just my theory)

 

dont know Max... just sharing.. if there’s wear, there’s wear. Odd that it’s in two different places, hence my theory on each. If there is misalignment between the cups, would think the fat rod would exhibit the wear at the end, while the thinner rod would have clearance. If the thinner rod is deflecting, it seems to follow the wear would be away from the ends. I’ve often wondered if the thinner rod harmonically whips while the fat rod wouldn’t. Just sharing what I saw...

 

Don’t think my rod had any such marks on the shaft.....just the ends, which Greg says is from his manufacturing process.

 

for sure.. my picture was to help illustrate how cup misalignment may affect both rods, not just the fat rod or just the OE rod. No bad intentions.

I do believe the larger the end radius the easier the misalignment can be hidden/masked. If the end radius of the rod is smaller, it would show up more drastically. After studying this over the last day or two, I think that may be some of the issue in my particular case. The other factors could be tip to tip runout or concentricity (either rod, OE or not), and rod straightness. My apologies as I’ve been vocal about the situation, but as info is exchanged, I think it’s the catalyst to improvement. I’d love to know why the stock rod has wear on it. Harley sucks on tolerances, and the consumers are the ones stuck in the end..

 

OK... So it's more your observation than theory.

 

LOL, I guess, although I can’t really see down inside the mainshaft while running at highway speed. That’s why it’s theory here... maybe speculation. Maybe hypothesis. Whatever word, lol

 

If the fatrod turns with the mainshaft its going to wear the shaft end on the slave cylinder as the slave is stationary and not intended to have a spinning rod on it. It may also damage the slave cylinder piston itself. It could also be the noise some have noted once the fatrod is installed. All in all, not a good thing to have taking place. Yep, when you place an oversize rod through the hole and not finish things so they are precise your asking for trouble, that's a given. The manufacture is responsible to look at that, all up front, before producing a product IMHO. I have not run a pin gauge all the way through the mainshaft to see what size it shrinks down to in the middle but I would guess they are not all the same and there could be some concentric issues in there, along with having a very loose tolerance in that area. You would have to check 10 - 20 mainshafts to make a good educated guess on what you might expect to see for a size range. It is most likely not a critical dimension in HD's eye's to start with, as they know that they have room with the smaller shaft size they run. Only the outer ends are done for the mating parts that fit into them with the necessary clearance.

Going from memory it was only about the outer 1 1/2" area that was the larger size as I recall on each end of the mainshaft. Like i said I never check the final size all the way through the mainshaft. I do not believe a little pushrod spinning is any big deal but spinning at or near mainshaft speed is! The long length of the rod only needs a small amount of misalignment, end to end to take up what little clearance room there was to start with. One other thing I seem to recall is the adapter that fits into the clutch hub side was a stamped part as well so it does not run true and kind of floats under the snap ring some. That could help or hurt in the right cases. Too many things are unknown but the wear showing in the pictures is real and not just from the machining process of the fatrod.

 

This is a funny thread. The MOCO does not have a fix for this problem. Actually their "fix" usually makes the problem worse. The best remedies have come from a couple people outside of the MOCO.
DISCLAIMER: I currently do NOT have a transfer problem. BUT if I did I will get the "Fat Rod". I would rather replace a the worn end cap every 10 to 15K miles than drain the primary and fill the trans every 1K miles or less.

 

Well, I haven't had any input here lately, so here goes.

I think the reason the fat pushrod works is because it does turn with the mainshaft. I think the clearances are close enough the oil adheres to the rod and the mainshaft causing it to turn as one unit, so it sets up a solid block to oil trying to migrate across the mainshaft. If the ends are machined the same as the stock rod so that the contact points are close to the same I don't think the little bit of wear that will be seen will be significant. Remember, it runs in oil. Occasionally you might have a mainshaft / fat pushrod combination that the tolerances are too close, those will have to be dealt with. Now, if the end is so narrow it is causing wear in the bottom of the cup, it could be a problem if it ever wears enough to penetrate the actuator plunger. I have an idea that could take longer than the life of the motorcycle, but to ease peoples minds I would make this problem go away.

 

Stone, it appears the fix is a moving target. I remember many many threads ago when the 3 piece was going to be the "fix". I also remember a Harley technician saying he thought it was going to create other problems. Now I'm starting to get it. I see the FATRD becoming a real player in this debacle. I also see your original "fix" as a more difficult to install option but I cannot see any downside, an I correct?