No, there were two flats on them. No problem. There were arrows on them showing the orientation, if I recall.

 

Everything I've ever been able to find...read...hear...learn...has led me to believe lifter cuff failure (by itself) is so rare as to be a statistical non-issue in reality. It can happen but so can a myriad of other unlikely things. Primary lifter failure on the other hand is well documented and much more likely to happen.

I admittedly got fixated on the billet cuffs when I did my work. Fuel Moto told me it was a coin toss and some guys do it while others don't. I figured 'why not' as long as the cuff bolts came out nicely, which they did for me. I'm not sorry I did them, but I also don't think they're doing me a lot of good...again, statistically speaking.

 

So they are different than the originals..

 

 

Nothing wrong using them if your in there especially with a high performance motor.. It might save the cases if the lifter fails. The lifter bore can tolerate some damage to the sides at the bottom and still be useable if it's a pin failure (common on the 99Cs) and caught early enough..

 

Check this out off YouTube. It apparently happens.

You Tube

One other thing I have learned from recent research is that the housing bores are inconsistent.

You Tube

 

Again, the video shows the aftermath of a failed lifter. How it got twisted in the cuff is speculation. IMO, it probably spun after the lifter failed, not the other way around. Sure makes for a good reason to sell an aftermarket part though.

 

did you stick with the stock cuffs with your 128 build? Just curious. I did go with the S&s cuffs with my stage 2. When I asked fuel moto about the switch they were honest as usual. They said there are not a lot of reports of stock plastic cuffs failing, but why would you not while your in there. Again they are cheap plastic. The cuffs and plastic intake had to go. Also went with S&s lifters.

 

I'm admittedly a non-expert on engines. I'm only speculating on the oem lifter cuffs. I think H-D probably had a good reason for going with the plastic cuffs, which was to prevent wear on the lifter if there was contact between the two surfaces. There's just enough play between lifter and lifter bore for a lifter to possibly rub or make contact with the cuff. That's why the cuffs exist in the first place...to help prevent lifter rotation, and to keep the lifter tracking straight as it reaches the top of it's stroke. If there's a tradeoff in going with plastic it would be durability and strength, though neither of these probably matter as long as everything is properly within spec'd tolerances and working correctly.

The main concerns I had with installing billet cuffs were 1) bolt removal and 2) adjusting the cuffs for lifter clearance. I didn't have any problems with either. Obviously the billet cuffs need to barely clear the lifters or the potential for friction and undue wear exists.

Based on CR's images of the parts involved, I feel very strongly that lifter failure happened first...leading to distortion and forces that caused rotation which the plastic cuff couldn't resist. A billet cuff wouldn't prevent lifter failure in almost all cases, but I suppose it might inhibit rotation during failure and could thereby reduce fragmentation and perhaps some engine damage. Complete speculation as we await the outcome here.

 

I am not arguing with you. You know this better than me. I’m learning after the fact from behind.

You originally implied the cuff was not broken or damaged. Mine looks great but the tech said it was turned. You’re probably 100% correct, just showing that what my tech described is also documented with another bike.

I want to help others see what can happen. Mine will have the better cuffs and lifters moving forward. The question now is what lifters.

Thanks