The beast was cobbled together with a MAC 4-into-1 exhaust, early model SOHC carbs, dried out UNI foam filters, 750K model rear fender, 750F model seat and black rattle-can paint veiling the wrinkles of age. It looked hideous with those awful stock bars that make you sit straight up. I felt the bike still had it's soul and was better than it looked. Probably just needed to be timed correctly and carbs cleaned to work well. I think I'm the type of person a seller loves to see walk up. After working on it a bit more, my guess is someone hacked this thing together, giving it the mere illusion of a motorcycle. No problem, my intentions were to give the illusion of a racer.

Without even riding the beast I knew the upright handlebars had to be changed. On the 750F, the conversion was pretty straight forward. I picked up a pair of 35mm clip-ons from Race Products in the UK, removed headlight ears to make room for the clip-ons, dimpled the tank to give clearance for my hands and fabricated a nifty bracket to mount the headlamp and clocks. It was like one-two-three. The bracket gives clearance for cables, brake lines and wiring, while making the front end look lower and cleaner than the stock mounting location on the upper triple clamp. I'm still waiting for the welds to break on the bracket to force a redesign.

To bring out the performance of this machine, I searched for the numbers to do some maintenance.

Valve Clearance

intake valve lash 0.002 " exhaust valve lash 0.003 " adjusted at the proper "T" mark on the advancer

Ignition Timing

point gap is 0.012 - 0.016 inches and should just open at the proper "F" mark on the advancer

Spark Plugs

NGK D8EA gapped to 0.024 - 0.028 inches

Cam Chain Tensioner

Adjust the cam chain tension by running the engine, loosening the tensioner lock bolt and manually pushing the plunger with something like an allen wrench and locking it down when the chatter subsides.

Carburetors (28mm "K" style adapted to "F")

Stock jets are K110 main and K40 pilot with float height set to 26.0mm, Idle air screw 1 3/4 turns out

Oil

The oil has to be drained from the remote reservoir and the bottom of the engine. Filter is removed at the front, just behind the header pipe. The capacity of the bike is 3.7 quarts of 10W40. Fill with the first two, turn the engine over and top off with the rest.

Drive Chain

Stock 77-78 CB750F bikes have 14T front, 43T rear, 630 chain; sag is 1" at middle. Mine is running the 17T front, 48T rear, 530 chain like the stock early 750K and 750F bikes.

Tires

3.25Hx19 front, 28psi (max load, 32psi); 4.00Hx18 rear, 28psi (max load, 40psi).

While moving dirt and grease around the bike, I noticed a crack growing across the beaten 750K fender. I estimated a couple more months of metal before I lose the brakelight. So, with the clock started, I began to sort out the seat, rear fender and lights. I had actually been thinking of mounting a replica CR750 seat, because it looks so cool. This seat design was originally offered by Honda as part of a kit to convert a CB750K to a racer. The tail section has tabs at the rear to attach the seat through the stock fender mounting location on the "K" frame. Unfortunately this CB750F frame is a little different at the rear, with the rear fender mounting bolts about three inches farther back than the early "K" frame. The "works" type seat might be a better fit and only requires cutting the frame just behind the gussets for the rear shocks and attaching a loop to hold the end of the seat. Either way, I was having difficulty imagining how to attach the fiberglass laminate seat so it wouldn't break. So, I decided to make my own.

Future mods are a long tank that fits the seat, relocate battery, oil tank and electrics, wire spoked wheels with alloy rims, paint and polish, personal inventory, make amends and pass this cycle on to someone else. In no particular order.