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CR750 Replicas

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Phil:
Hi - I am putting together a CR 750 Replica and would welcome advice, photos etc of the genuine article. I have two engines - a K7 and a K6. I believe a K7 is an unpainted F2 and will have bigger valves and combustion chamber (?). Similarly it has a closer ratio gearbox. I intend to use a special 836cc Dynoman piston kit, race cam (Megacycle or Dynoman), s/steel valves with titanium retainers, stronger springs and Keihin CR 31mm carbs. I want to use standard rods. I need someone to port the head and fix the new valves and guides - anyone know anybody? The K6 engine will be tuned to rev higher and will use a Nova c/r gearbox and Carillo rods, etc. Any help/advice most welcome!! Phil (philipclark2@mac.com).

Voxonda:
Hey there Phil,

First the K7 is not a unpainted F2, I personally think the K7 is the better of the two. The advantage of the F2 is that it produces more power, but at a cost. The head of a F2 is crap, due to the sharper cam and the bigger valve the valveguides wear out very rapid, hence 'smoke' and oil consumption. Have build a Japauto Endurance replica with a K6 engine and am in the process of building a 850cc Turbo based on a F1 engine. Look out if you're using a sharp cam and heavy springs, the construction of the 'camtowers' cannot take to much stress. There are lying a lot of blown engines around.

Cheers, Rob

Phil:
Hi and thanks for the response. I have obtained parts books for F2 and K7 (thanks to this great site!) and you are correct: the valves on the K7 are the same as K6 and different to F2. I also note that there are slight differences in the gearbox. The K7 and the F2 are identical, according to part numbers, but different to the K6. Is this the 'closer ratio gearbox'? I want to run a standard gearbox on this engine so this is a bonus - or am I missing something?

Phil

SamCR750:
Hi Phil, check out my bike in this thread. http://forums.sohc4.net/index.php?topic=25400.0

Also check this thread in same forum.  http://forums.sohc4.net/index.php?topic=27902.0

PM if you need any further help.

Sam. ;)

Phil:
Wow! That is a lovely bike! The thread is interesting. The original CRs are very rare birds indeed. The only one I have seen in the flesh is in the old Honda museum at Suzuka. Sadly they would not let you take pictures (they do now). Is that the standard rear hub on your bike or one of those expensive magnesium jobs? What are the footrests - Disco Volante? Did you beef-up the cam holders? I have 101 questions ...
cheers,

Phil

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