Not sure it's a casting issue but Steve Cole mentioned if the rocker arm shafts are not tightened evenly, the rocker support in the head can snap off. On the rocker shaft, they changed the chamfer on the hole IIRC.

 

Thanks, guys. Max, yes I mean the cylinder head. And that's interesting about the rocker shaft changes. If they changed them, then I should be getting the new version of them. That makes me feel good. And yes, I have the stronger valve springs.

And Joe, you're right: that's exactly what the dealer said, that the valves did close, avoiding any damage to the piston. I did ask about the replacement of the pushrods, but they didn't see any damage. And I haven't had any chatter to speak of, so I don't know that I need adjustable rods. I go back and forth about those (on my shovelhead, people use them a lot when they take off the rocker boxes). For now, I'm going to leave what I have on there. I did ask why they were replacing the lifters - especially if they weren't replacing the pushrods. They were concerned about the bearings in the lifters being a potential issue down the road, perhaps because of whatever happened in the breakdown. I'm not sure I follow this reasoning, but I guess it's possible they took some sort of stress when the rocker shaft broke, thus potentially compromising the lifter bearings. But I'm getting new ones. These are the upgraded SE lifters.

Dealer said the cylinder is about a 15 day turn-around from the factory, in normal conditions. I don't know what sort of delay I'm going to see with COVID-19 raging across the country. Because I can't ride anyway, I'm taking an academic view of this whole thing and I'm curious how this will play out from a supply chain standpoint.

 

I have no personal experience with them, but I do know that many builders claim that the SE lifters are junk too.

 

There's always a better after-market solution for just about every component on the bike. I don't ride the engine hard, so I suspect lifters that are even slightly better than the ones on the 10's of thousands of properly-operating M8 engines out there will likely be fine for me. They weren't the part that died, after all.

 

Glad this is getting sorted out for you.
I have having less and less confidence in my two M8s ... which I plan on leaving stock for two years.

 

Well I love the way the bike ran. The handling was fantastic. And the M8 has a lot of pep. I'm going to write this one off as a one time thing and see what happens from here.

 

I also snapped a rocker arm shaft. I have upgraded using S&S parts to a 124. Builder said he has seen some do this with the increased HP and the heavier springs. I had to chase down the parts which came to less than $15 but 4 hrs of driving. The builder was nice enough to not charge for the replacement. Unlike yours though mine started with a ticking sound, I just thought the bike hadn't warmed up (engine was relatively new to me at that point. A mile or so later all hell broke loose. I could tell it was something in the top end but was thinking a rocker arm. Fortunately, like you, I had no other collateral damage.

scott

 

Looked all over on line. Don't see S&S rocker shafts for 2017 and beyond. So that doesn't look like an option. I'm not going to a 124.

 

I got her back yesterday. Thank goodness service departments are considered "essential". They said 2 weeks to get the new cylinder for the factory but the whole repair was done in a week. Had a nice ride home to give it a test. Ran great. I hope this is the only big ticket thing I have but I'm a little nervous. Kinda like a relationship. She let you down once, you still love her so you continue on, but you're a little wary. This gal has to earn back some trust! I have lots of plans (shocks, seat, bars, floorboard extenders, audio, head unit) but I'm gonna log some miles before putting any money into her. But again, she's running well now. Of course, that's what I thought when this all happened, too. As a positive, I would say the extended warranty probably paid for itself on this job alone.