Board index Flathead Power-Technical Questions, Answers, and Suggestions K-Models rake of K vs KH

rake of K vs KH

Post Wed Apr 30, 2008 12:51 pm

Posts: 217
Location: Palo Alto, CA
Hi everyone,

I am guessing that the -52 neck casting has less rake than the -52A casting, and was wondering if the lower fork clamps & stem were also this way?

I have heard that flattrack racers like to use the -52 part - was this because it reduces the rake, or increases it to compensate for the rake built in to the neck casting?

Thankyou!

Post Wed Apr 30, 2008 1:39 pm

Posts: 591
Location: Crewe, Great Britain

Hi Suicide Shovel,

No, the 52/53 frame rake is the same as the 54/55 frame rake.

They changed the fork rake by modifying the top and bottom tree.

The 56 frame was in fact the same frame and angles with a bit of a goose neck to lower the whole frame by 1" in relation to where it was before.

I still have my 54 KHK original trees/forks, my bike is about 200 numbers after the rake change: They are actually K trees that have been factory moded to the new fork angle by welding... Morality, H-D didn't throw anything away, it can always be moded!!!!!!!!!!

Patrick

Post Wed Apr 30, 2008 1:58 pm

Posts: 217
Location: Palo Alto, CA
Thanks Patrick, so do the earlier trees reduce the rake?

BTW from examining two 53 frames, I can conclude that the change to the 52A neck casting was made early to mid-53. The 52-early 53 frames have no date code, and an upper engine mount with a -52 casting number that is absent in the mid-53 frames onwards. The very early frames seem also to have very crisply defined casting numbers.

Post Wed Apr 30, 2008 2:04 pm

Posts: 591
Location: Crewe, Great Britain

Hi again!!!

My tired brain still have difficulty in differentiating rake and trail!!!!

The earlier forks have less trail and more rake. The later ones have more trail ans less rake!!!

Yes, the more recent they are, the uglier the castings... The late 70s Sportster's ones really take the bisquit on that account...

Patrick

Post Wed Apr 30, 2008 2:08 pm

Posts: 217
Location: Palo Alto, CA
thanks again Patrick! So I'm thinking the set with more rake will be more stable for high speed use...

Post Wed Apr 30, 2008 2:21 pm

Posts: 591
Location: Crewe, Great Britain

No, more trail is more stable... So later geometry is more stable, but less easy to flick about...

patrick


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