1961 CB72 Project

sarals · Post by **sarals** » Wed Aug 05, 2015 10:23 am

I know. My computer froze on the upload, and that's how it ended up. Maddening....

:)

G-Man · Post by **G-Man** » Thu Aug 06, 2015 7:42 am

Sara

Cannot find Freddie Spencer. This is Barry Sheene at Donington around the same time.

He was past his best but still looked stylish...... :-)

G

sarals wrote:I know. My computer froze on the upload, and that's how it ended up. Maddening....

:)

G-Man · Post by **G-Man** » Fri Aug 14, 2015 2:36 pm

Had to make a trip to pick up the latest batch of chrome plating from Prestige this morning. They don't like to be kept waiting once their work is ready. Their turn around time is a little long so it's always a pleasant surprise to see what they have for me.

It seems like ages ago that I prepped these "not quite so early" shock bodies. They are the ones that came after the early ones with alluminum covers but befor ethe ones with the welded-on clevises and plastic top covers. These ones have steel top covers similar to a CL77.

I really like the built-in lower clevises which are similar to CB160 but a bit more sturdy. I asked Prestige not to polish the 'as cast' sides of the lugs to keep them original-looking. The stops for the preload adjusters are spot welded rather than brazed-on like the really early ones. One pair of these is desitined as a durable spare set for my 1961 CB72, one pair will go to Alan Curtis for his 1962 CB77 and one pair will go on my upcoming 1962 CB72.

I just have to find / make a set of suitable internals and find some covers for each set, now....

G

G-Man · Post by **G-Man** » Fri Aug 14, 2015 3:00 pm

I managed to get a bit more head-work done. After getting the seats to a nice width I lapped each valve with fine grinding paste.

I don't like the slots that Honda put in their regular valves so to clean them up and to help get my valve lapping suction cup some purchase, I clean up the valve face just enough to get rid of the slots and to give a nice finish. Hopefull it will help this engine, with its higher compression 010 pistons to avoid detonation.

It's always a chore getting rid of all lapping paste from the head afterwards so I managed to suspend the head on a couple of bars in my ultrasonic cleaner. All trace of the paste and my grubby fingerprints were erased to leave a nice bright surface.

The cleaner makes a nice job of the hard to reach parts of the cooling fins, too.

You can see the difference that a dunk in the tank makes here....

I made sure to mark the lapped valves and their respective locations and put the head away clean and dry ready for putting the valve springs in when I get my next bout of rare workshop time.

G

R100 · Post by **R100** » Fri Aug 14, 2015 3:15 pm

Beautiful work G-Man.
I think you are right about the compression. It will probably come back closer to where you want it with that slight dishing of the valves.

Steverino · Post by **Steverino** » Fri Aug 14, 2015 4:10 pm

Thanks for the update. Your work is inspiring. No detail is too small in your pursuit of perfection. I wish I had access to the level of plating service you have in the UK.

G-Man · Post by **G-Man** » Fri Aug 14, 2015 4:30 pm

Steve

I was talking to them today and they are fearful that they will be put out of business by upcoming "eco laws" on chrome. That will be a sad day indeed......

G