HarleyTechTalk

By (real world) I mean first hand experience, not "I read about it" or "someone said." In other words it actually happened to you, or a friend, and you saw the results, or you're an independent wrench that has repaired such a failure.

FYI, I picked up a pair of these "new" that have a MFG date of May 2022 on the box, and I also have a CR512 cam. If I use them with my current 130 BBK my compression will be +/- 11:3.1 depending on the final deck height of my pistons.   

My local HD service advisor told me that they've installed several hundred of these heads with cams that don't exceed .540 lift, and have not had one fail yet... However, it seems that I'm the "guy" it'll happen to even if it's the first ever recorded failure!     

I know the original CNC ported SE heads have had a lot of stage 4 failures not shore on the extremes,but for the price I would change the springs with adaquit  after market springs from Star Racing or Cycle Rama,while your at it change the compensator ramp also.

I also asked the service advisors that I called about comp ramp failures, and they all reported failures even in completely stock configurations. So replacing it with an aftermarket unit is good advice. 

    

  

 

I had a customer bike ,Roadking 114 cu from 2017 ,stage 4 with broken valvesprings , bike had 10.000 miles when it happend .
I noticed that the max engine rpm in the tuner ,that came along with this kit , was set at 7000 rpm's !
Customer was on the highway and wanted to let the bike run like hell,all the way up the scale to 7000 rpm and then the spring broke . I replaced oilpump/valvesprings/cam /lifters in favor for an S&S kit .
Bike pulls a lot harder and boosts 134 rwhp ,and no problems with valvesprings breaking .

"My local HD service advisor told me that they've installed several hundred of these heads"

That alone would have me thinking that service advisor was handing out a load.

Moonshine HD say they have had them break. They have a Utube on the subject I watched em swap them out for a big name brand 

I have a low volume shop in a rural area. I have had two sets of SE heads come to me with broken valve springs and the resulting carnage. Weld 'em up, new guides and seats as necessary, AV&V valves, guides,  and springs. I've seen a number of stock M8 heads with cracked/broken rocker stands on the left side (sprocket shaft side) of the head. Again, weld 'em up and re-machine them. Crummy design!