K7 F1 engine parts on a K0

[AshimotoK0]

Hi everyone,

I tried to get a reply to this one on the US site but surprisingly no response.

My 750 K0 was purchased with 40 odd K miles on the clock and had not been used for about 17 years so I never heard the engine running. I have a heap of new or low miles parts for it including crank, barrels and pistons and new genuine chains etc. The original top end I am sure has been replaced as it is in very good condition and there are seals on both inlet and exhaust valve guides.

Here is the question  -  I have quite a few parts from a K7 and F1 engine and these include complete clutch (with the double 'B' plate), shifter forks and shift drum. Since these parts were upgraded on the later bikes (as detailed in Honda Service Bulletins for better transmission shifting etc.), is it worth me using them instead of the original K0 parts? Obviously I would retain the originals for historical reasons.  Also are there any other 'upgraded' parts I should look at using from the later engine?

[Seamus]

Interesting question that one. The only way to be sure is to compare with the originals, then fit them and see if they work on the bench. I would guess that you would be OK. The big plus is that bits inside don't show and no one would be aware of their presence, and you get a better developed part. (This does'nt run true for some of the heads though).

Seals on exhaust guides came in later (K2 I believe) as I suspect that you already know, so you are probably right in that these were replaced at some time.

I guess you also know that the early heads looked different to the later ones (from mid K2 I think) as the ribs between the fins were in different places.

Hopefully some one with more experience will agree with this.

Good luck

Seamus

[steff750]

hi ash it might not be what you are looking for but i got a f2 engine in a k0   i have a copy of a bulletin board showing how too put the k7 clutch internals into earlier ko's putting the bigger plate B in the middle and using the heavier k7 clutch basket it was supposed too eliminate clutch rattle, i have used later k series carbs they work great and mixed and matched gears, camshafts ,camshaft housings,gear selectors,rocker arms rocker shafts,but the final drive bearings are bigger on the k7 and don't fit in the  k0 cases, a friend of mine said that if you put Honda 900 pistons in a 750 it take the 736cc up too 810cc and you dont need to bore out the cylinders  

[AshimotoK0]

Great response- thanks folks - maybe we are more adventurous than our US buddies! Probably due to them getting engine parts dirt cheap there secondhand.  I have already researched it a bit and I think the parts will fit so long as you use the entire K7 clutch assembly. Having never had a CB750 before I don't know what the gearshifting is like, and how it improved over the lifespan of the SOHC's (I had 4 400/4's and a Z650). I will definitely keep the K0 parts though-just in case I ever need to part with it to a 'purist'. Do you ahve any links to that bulletin board article please Steff?  I think my head is a proper K0 as it only has the single 6 mm bolt. Has anyone tried K1 barrels on a K0? - I got some 20k miles barrels and pistons fitted with new rings for my bike. Or do I swap the liners over?

[steff750]

 hi ash here you go try this link     http://data.sohc4.net/Clutch_rattle.jpg   if it don't work go to main sohc site (USA)and have a look in the tech section its under clutch , there are lots of other bulletin boards as well so well worth a peek,   knowledge is power
BTW if your barrels look good no broken fins i would fit them don't bother changing liners too much hassle they will be the same except you will have extra stud hole on the front that cant be seen anyway