73 cb starting to take shape

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You are oh so close ben!  I am sure you have told me in the past, but what all did you do to the engine. I see the CRs, so i am guessing 836 with some porting?

Well, let me see, The whole business started because I bought an old original bike with 7k miles on it and noticed a headgasket leak. That was before I noticed it had been in a head on accident that left the steering stem bent, and as I later found had sheered off the oil filter flange, precipitating an artistic attempt to weld on a new flange by some  maniac who could form aluminum blobs to tack a new flange, but left a large hole that probably did not help filtering.

I replaced the steering stem, polished and used the original races, and fitted new balls. The inner fork tubes had been replaced but the lowers bore signs of the head on as well. JB weld in one of the fender mount holes, retapped, presto!
So what, I did not have much into the bike!

I had rebuilt my top end twice before with Mike Rs help(as time went on more and more help from Mike, until this last build which was mostly Mike). First time with a higher lift, longer duration cam, heavy valve springs and a little porting. Dyna S. Blew oil into the compression chamber. Next decked the cylinder casting and head, heavier cylinder studs,more porting, bigger exhaust valves, hardened lifters and cam lobes. Stopped oiling on one side after a couple of hundred miles, spewing metal vomit everywhere.

This time, Started from scratch. I had a set of later cases that I had squirreled away with 4 oil returns rather than the earlier two. Balanced and lightened crank, Carillos, more head work, hardened everything and cam from my bosom buddy Barbara at Megacycle. Ti retainers, big exhaust valves, more decking, 10.5 836cc JE pistons and rings. Compression probably higher than 10.5 due to significant removal of material to make sure jugs and head were flat. Undercut and polished tranny, heavier clutch basket,springs,extra plate,  Dyna 2000, coils, and wires. CR carbs. Flanged stud nuts allowing higher torque during assembly. Completely rebuilt  oil pump. Earls oil cooler with spin on adapter by Terry from Australia, which allows more circulating oil, somewhere around 5 quarts.
Probably other stuff I cannot remember.

Wow....that thing is going to have some pep.  Have you had the engine running since the lastest rebuild?

Yes, about 100 miles, and I have started it up each month and run it up to 180f( I am running an oil temp gauge as well as oil pressure)
I will be replacing the jet needles with a leaner taper as the big could pull more at 4-4500 RPM. It was a bit difficult to tell what it had on tap as my front brake was partially seized, but I figured that would be good for the break-in. ;D

I think I will dyno it at some point to see what I can do to optimize timing and fuel metering.


Here is a photo of the Earls oil cooler you asked about


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