harleyKmodel

I was told that the Harley factory race dept. did the finish work on all KHK models in 1955 and some early KHKs were fitted with KR heads due to a shortage of KH heads. Is this true or just another myth. I'm new to k Models (I've owned a few other flatheads) so I need an education. The heads on the the early 1955 KHK motor I just got use long reach plugs and have a -52R cast number I was told these facts indicate KR heads.

Yes, these are KR heads, but they were installed by a dealer or customer, not by the factory.

Std KK/KHK factory heads are slightly reworked versions of K/KH heads.

Patrick

Thanks for your input.

Thanks for your thanks...

These days, most folks come in here, ask, get a sensible reply and then just ignore you!!!

Where's education gone?????

They run great like that. I started buying every K part I could starting in the 80s. Many subtle changes some big through the years without much info. For a motorcycle that almost didn't happen. Often I've found non factory changes people did like your head swap and figured it out later. My first 56KHK had Chevy Intake Valves, 2mm larger than KH, KHK. So at first, ah, KHK valves are a little bigger! Than John Clued me in, no such K valve, and than I noticed the Chevy Style. So after collecting over 20 Ks at one point I started comparing parts. Many small changes some big. Lots of fingers had been in the pies also...haha. Erik

Chevy inlet valve in 55 KHK:



BIG

Patrick

Erik and Patrick, Are those Chevy valves from a 265 6 cylinder or from a 292 6 cylinder? Always, thanks for your great information and responses. Regards, Ron

My 54 KH also has KR heads. I'm guessing the big difference is the combustion area has been shaped for maximum flow - particularly for the KR valves, which are much larger than KH or KHK valves (I have KR valves in my KH cylinders). A side benefit of the KR heads is the brass or bronze spark plug hole inserts. Stock heads often crack at the spark plug holes, and I think the factory solved this problem for the KRs. I've been using NGK BR8ES spark plugs.

BTW, Enfield Racing sells the KR valves should anyone need them.

Hi Ron and folks. Here's my current mill. The one I use is a Sealed Power V1076. 235ci 1956 Intake Valve. 30° Angle, 1.76"? Head (2mm bigger than KH) can cut head down if wanted. For KHK you cut the stem down some and slot for keys. Leave a nice chamfer. I think KR valves might be 2mm larger again...The Chevy has the KHK Stem diameter. With 5" Strokers leave the stem length. and motor up!

Dave yours must run really nice! When they loosen up a little they go!! The Flathead makes its power with flow, not compression as far as conventional hop ups go. Len Andres racer/genius put the number at 5.99 to one for the high rpm KR. After watching my E420 cam & valve action it looks more like a 3 stroke than 4. Haha. Lots of breathing going on through open doors. The KR chamber is ideally designed to help the flow reverse direction and direct combustion a bit closer to the crown. The KH KHK heads are similar, with a definite shift on the Shelf location, and Chamber Shape, little more rounded, longer. Ice Cream Cone is what I called it straight out. Erik