Topic: 'Homemade' rockershafts CB750 k2

[CB350 Four]

Hi,

I've been busy with my dad's CB750K2. The bike wouldnt rev over 5k, so it was about time. The rocker surfaces were all gone, aswell as the cam it self. (probably due to those pressed-in oilrestrictors, and a previous rebuild in the 80's which apparently involved using a gallon of liquid gasket)



http://s292.photobucket.com/user/Hard_Ospers/library/CB750K2?sort=3&page=2 (more pics for those interested)

So i got a used set of rockerarms and a cam. I also installed new (cruzinimage) pistons, rings etc, because why not. Tossed the whole cilinderhead in a ultrasonic cleaner to unclog the oilpassages. Also had new valveguides installed with seals on the exhaust side. Robs HP, but my dad doesn't use it anyway. It add reliablity from what I read.

The original version of rockershafts had 1 groove in the middle. The ones I got with the used set have 2 setscrews. I read Hondaman's thoughts on the difference between these, and concluded I don't mind some noise if it makes HP and durablity. So I'd like to go with the old version, if those weren't so screwed up from lack of oil.


Start here to get to my question   
My idea was to get 1000mm of this 12mm h6 stockshaft to make my own. And also add 2 oil grooves on either side for the rockers.
https://www.damencnc.com/nl/componenten/mechanische-onderdelen/lineaire-rondgeleidingen/144
Diameter ISO h6
Hardness 62+-2 HRC
Steel CF53

I have a machineshop help me out. I know it fits and doesnt bindup, they had a small piece to testfit.

Problem is that the old shafts are smaller than 12mm; around 11,57. The inside dia of the rockers is 12,02.

Will a new 12,00 shaft screw this up, because there won't be enough room for a proper oil-film?

Thanks

[70CB750]

That 0.05mm is important IMHO.

[Bill/BentON Racing]

I got good condition old style shafts!

[CB350 Four]

Postage to the Netherlands will probably sum up to the same costs as here 

What is the STD diameter of these shafts? Shopmanual only lists max. play between holder and shaft.

Maybe i can order to the correct size.

[Bill/BentON Racing]

I'll sell you 4 good ones for $50.00 USD. plus shipping. Bet we can ship for $25.00.So if it's worth  $75.00, we can do it, Bill

[CB350 Four]

Thats sounds very tempting thankyou. Can you PM me your Paypal number/adress?

[CB350 Four]

For sake of 'finishing' a thread with an answer;

http://www.enginebuildermag.com/2013/03/bearing-clearances/

Is says here that a minimum of 0,05 to 0,07mm clearance must be maintained for an oil-film to buildup. Thinner oil in blue printed race engines might allow for 0,03mm. They are talking about crankshaft journals, but I'll just assume the same goes for rockerarms.

I have asked the shaft company if piece of 11,57mm shaft can be ordered. Within a reasonable price range ofcourse, but I think it has to be custommade, which has a pricetag.

A guy from the machineshop might have the old style shafts for me. Otherwise Mr Benton has good ones for me.