Topic: F2 vs K6 head

[Dion]

Hi guys.
I the f2 has larger inlet and exhaust valves.
But I believe that the shape of the combustion chamber is different ...
Can the f2 head be used on the k6?
What mods are required.

[Jerry Rxman Griffin aka MuthaF'er]

You gotta swap out everything above the cases basically. Cylinders, pistons and head. I'd do the cam and springs as well.

[HB-1fan]

Thought Mike said once it was his preference to modify the 77' k head. He can correct me if I am wrong!!
I do have a K7 head on a fresh 836 that I would like to have him port.

HB

[Old Scrambler]

Yes, the F2-3 head has a larger chamber............so, as Jerry said, if you have K pistons, stay with the K head. The after-market suppliers make two types of 836 pistons........numerous suppliers of K type (also used for F and F1).......not so many for the F2-3 type. The valves and other parts need to be matched accordingly.

[johno]

This is a K head that Mike has on the go now. 34mm valves same as F head. but nice small chamber for compression, just that Mike has to work harder on the ports. ( he loves it dont you Mike)

K or F head you can have same valve sizes, to me the main two points of differnce is the F port size is a mm or two bigger  for flow ( just means Mike has to port a bit more or less) and the F head chamber is bigger so need to sort your compression options out.

I know being wise is often not in the equation but unless your into a class type competition the wise thing would be    bring what ya got"     and enjoy life with minimal stress.

[PeWe]

My K6 head has F2 inlet valves too Got it when ported at my local tuner 1983. EX still std 28mm.

[MRieck]

My K6 head has F2 inlet valves too Got it when ported at my local tuner 1983. EX still std 28mm.

That's interesting as the F2 valves are shorter secondary to the sinking of the valves/chamber.

[KJ790]

As others have said, the F2 head has deeper combustion chambers. There is room to run flat top pistons and shave the F2 head down to get the compression ratio up. I have an F2 motor running 836cc flat top pistons meant for a K model in it. I had to shave 0.060" off of the head to get the compression ratio up above 10:1, but there was plenty of room between the valves and the pistons to do so (check with your pistons first, as different pistons/cam combos may require some valve pocket relief). You will have to degree the cam after taking that much off of the head however.

[Dion]

U chaps r great. Thanks for all the info

[PeWe]

My K6 head has F2 inlet valves too Got it when ported at my local tuner 1983. EX still std 28mm.

That's interesting as the F2 valves are shorter secondary to the sinking of the valves/chamber.

OK, is that why I had to tighten the adj screws deeper on IN side?
Visible on the photo, less threads left for lock nut.