Cast-in main bearing race. A cast-in race means big bucks to repair, instead of just pressing out/pressing in a new race. Usually the crankcase will simply be trashed as it's not economical to repair.

Chain drive cams with a tensioner. Timing is sloppy, varying up to 4 degrees. Tensioner wear seems to follow no apparent cause/effect schedule, with some going well over 60k miles, and some dumpingat 20k miles.

No tappet blocks; they're part of the engine cases. When they wear out you might be able to go oversize once, but then after that it's new engine cases.

Heads are a good design, but don't breathe as well as needed if you get into much motor mods. That means more expense.

Connecting rods have no races so they're not rebuildable.

These are the reasons I wrote what I did about a "throwaway" engine. Don't get me wrong, there are a lot of really good things about the Twinkie motor, but I'm just wondering what we'll see down the road, 30 years from now. My point is, in my opinion (and we all know about how they smell), there are too many non-rebuildable parts on this engine. And I will admit that some of these may turn out to be overblown, but we'll have to wait and see about that. And since I'm over 50 I may never find out!

 

I reckon when my motor wears out I will get a new factory replacement. I have 32K now and expect it will go 100K. I like the fact that I park it and no oil spots, ever. I have ridden it hard on the slab going 80+ for hours on end and no problems. Gas it up and hit the starter and go. 7K miles last summer on one trip and no issues. It may be a throw-away but I think it will last a good long time. I did just replace the tensioners and will probably go to gear drive or the new chains when I go back into the cam chest. I now have all the tools so going to gear drive (if my run out is ok - haven't checked it) next time and it won't be so expensive.
Tnicean

 

Man your right, Ive never heard it reference to a bike before.

 

+1

 

My evo loves to eat twinkies.

 

I've heard them called Twinkies since they first came out.

 

My Evo likes to eat my own Twinkie (Night Train) just haven't gotten around to doing the 107" build yet

 

yep , harley folk are quck to nickname engines LOL I've heard the term since almost day one. I agree with poco , built like a bic lighter, shovelheads and evos more like a zippo