×Wednesday Workshop Special
Not quite the usual Wednesday Workshop Roundup today, but a special feature on the Honda CB750F Adrian’s been restoring for the last month or so.
It’s difficult to understand Honda’s product range thinking around the late 1970s as they had the CB750F DOHC, the CB900F DOHC and the CBX1000 in their sport bike line up, the 750 and the 900 being very similar. My take on it is that the CB750F and the CBX1000 were aimed at the American market and the CB900 at the European. Certainly the 900 was not initially available in the US and only customer pressure forced Honda to release it there, and while I remember lots of CB900Fs in the UK I don’t remember the CB750F being there. SA is a bit of a melting pot and just about every model of the Honda range of that period managed to find its way there, hence the proliferation of CB750, CB900, CB1100 and CBXs, seemly more so that the rest of the world.
This bike came to us as part of a job lot of classic Hondas we purchased about 18 months ago. It was in a dilapidated state, half disassembled, with what looked like many parts missing, the engine and other bits roughly sprayed black. Not good and we initially decided to use it as a parts donor. The redeeming parts were the tank and body work bits which had recently been nicely resprayed silver with blue decals, presumably the start of a previous owner’s restoration that never completed.
Adrian all fired up after finally completing his full nut and bolt restoration of a CB900F, after only 2 years! That’s actually not quite fair, the strip down, refurbish and rebuild took about 6 months, and some of that time was waiting for parts. Then it was discovered that during the vapour blasting cleaning of the motor, water and detergent had got in, so the motor had to be removed, again, then stripped and rebuilt and again so more waiting for parts from the UK.
So, as I said, fired up from the success of this CB900 project, plus getting both a CX500 and a CX500 Turbo up and running, he declared he was going to restore and rebuild this CB750. Great we said that should keep him busy for another 2 years. However, this time and unbeknown to us, he had a cunning plan, we also had a third CB750F at had already been stripped to component parts for spares and by using some of these parts he had most of the parts needed to complete a full bike. Plus, he seconded Robin to rebuild the motor right from the start. Major framework parts were quickly despatched to the powder coaters just around the corner, engine parts ordered from the UK and from Honda SA, and smaller parts sand blasted and sprayed in house. Big surprise was that Honda SA had piston rings and a few other parts in stock in J’Burg, they must have been sitting there for about 40 years, amazing, and even more amazing the parts were much cheaper than non-OEM parts from overseas.
In just over a week the powder coated parts were back, total cost R1800, not too bad, and the rebuilding commenced. Parts arrived from the UK and Robin build the motor putting in new piston rings, cam chain guides, cam chains, valves and refurbished cam shafts, the rest was in spec so reused. Carburettors cleaned, several times, and new jets, seals, floats, and needles fitted. More parts ordered from both the UK, David Silverman, and the Netherlands, CMS, unfortunately we can never seem to identify all parts needed one time at the outset of a project, which is a bit frustrating. Nevertheless, progress was made at an almost alarming rate, at the end of about three weeks the bike was basically complete, black plastics had been polished with boot polish, switch lettering repainted, instruments rebuilt, brakes refurbished, reflector boots resin cast, and electrics sorted. Wow, time to see if it will run, excited!
Well not quite yet, first the tank had to be acid cleaned and then epoxy coated internally, this is now standard practice for us as these old tanks may look fine but rust in the seams and other hidden places is a killer for the carbs. Not wanting to wait the 72 hours for the epoxy to dry, we set-up a small feeder tank and try starting, a few spins of the starter and the motor splutters into life, it runs. Well, sort of, after fitting the newly dried tank we discover one of the carbs is leaking, and then after that, its running very rich, carbs out again, adjust and now its running lean. Right now, as I write, Adrian and Robin are again removing the carbs for another look, but we have faith that all will be sorted soon. So not 2 years, not even 2 months this time, but about 4 to 5 weeks and around R10k spent on parts and outside work and we have a fully restored Honda CB750FA. Well done Adrian and Robin.
The picture of the finished bike shows it with a nasty black four into one exhaust, this is temporary while we wait for a second-hand original chrome four into two to arrive from the UK.