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Honda CB750-Four

Our Bikes - Honda CB750-Four K1 1971

(July 2020)

honda cb750-4

Stepping back in time

by Guy 'Guido' Allen; pics by Ben Galli Photography

It took several decades to once again throw a leg over a Honda CB750-Four - was it worth the wait?

There was a time, some four decades ago, when a very second-hand CB750-Four was my first 'big' bike. How times have changed. For a start, our definition of the term big bike has shifted enormously.


The history of the single-cam CB750-Four is all too well recorded. It’s widely blamed for the death of the British motorcycle industry in the late 1960s to 1970s, though many now accept the commercial collapse was largely a self-inflicted wound.

In any case, the humble CeeBee has developed legend status over the decades. It proved you could make a powerful and reliable multi while rapidly changed our expectations.


I started riding five years after this bike was built and, even then, the whole idea of an electric-start four was a topic for debate. “It’s a car with two wheels missing, mate,” was a very familiar argument. Too many cylinders and too convenient seemed to be the thrust. The implication was it wasn’t a ‘proper’ motorbike. A cynic in those days might have suggested that, ipso facto, a less reliable twin was a proper motorcycle. But who would be so cruel? (And before you get upset, I also own a Meriden Triumph...)


Former Motorcycle Trader mag Editor Greg Leech is to blame for this addition to the shed at Chateau Guido. He was the one who talked Brian Browne, ringmaster at TT Motorcycles in Mornington (Vic), into building a CB-based café racer as a give-away bike for the mag some years ago. It was a stunner. Without that connection, none of this would have happened.


I kept in touch with young Mr Browne and one day made the mistake of asking what was happening with the gold Honda in the corner. Given I can’t write an Irish accent, you’ll have to do your best with this: “Oh that,” he said, “Well I built that for myself but don’t get much time for it, so I’m wondering why.” Okay…how much?


The number was up there for the time, but given it was a top-to-toe restoration, done by a former Honda dealer who could build in details no-one else could, it seemed reasonable. Looking back, it was a bargain.

Honda CB750-Four


Its only wrinkle was Brian fitted a later fuel tank, because he preferred a left-side fuel tap, when the original was on the right. I’ve since bought an unrestored early tank and put it away, which will be sold with the bike. One day, far away.


Honda’s first CB was the K0 launched in 1969, which have become a hugely popular target for the investment end of the motorcycle market. Those bikes now have dedicated clubs and restorers. You can buy a fully restored/remanufactured version, but don’t expect any change out of US$40k (Au$60k) for a very early 'sandcast' example. All up, there were 7414 units built with gravity-cast engine cases.


Thousands of K0s and K1s were built, but survival rates are incredibly low. Keep in mind there was a time when a well-used one was worth next to nothing - it was just an old Japanese bike. One of the reasons they found their way on a trailer to the tip, which few people talk about, is the engine’s Achilles heel was pin-holes for oil galleries feeding the cam bearings and rockers. They were easily blocked and scads would have died thanks to poor maintenance and over-generous use of silicone-based gasket sealants during rebuilds.


Thankfully, this one survived.


It had been over a couple of decades since I’d ridden one of these things – I’ve owned three over the years – so I was more than a little curious to finally throw a leg over one.


Reaching for the ignition switch under the left front corner of the tank was a little weird, though the minimalist choke lever brought memories flooding back. So too did the distinctive flat drone of the long-stroke engine as it happily burst into life. I swear it’s unique – there are lots of inline fours out there, but a CeeBee has a cadence that is its own. For just a moment there, I was 20 again.


Geez it’s heavy. With the wide bars, the lairy paint scheme, and oddly menacing note from the engine room, you would have felt as though you were dealing with alien technology back in 1971.


Get it rolling and it’s a big happy motorcycle with plenty of straight-line urge. The carburetion is good, it’s smooth, and it’s a comfortable ride.


Tip it into a corner and you soon discover its limitations. This resto includes the original FVQ rear shocks – unkindly but accurately known in some circles as Fade Very Quickly – and they’re ordinary. Comfortable in a straight line, they bounce around menacingly when you are pushing on and hit a series of mid-corner bumps.


As for the front brake, well, we're talking early seventies – hardly a high point in disc technology. Treat it with caution in the wet, as the polished disc takes time to dry out and bite. It's okay in the dry. The rear is a drum and works fine.


Past experience has taught me the frame is also severely tested with any serious corner velocity – it can and will flex. My 1975 T160 Triumph will run rings around it in the handing stakes. Back off the pace to halfway sensible cruising speeds and the situation is a perfectly happy one.


With all those foibles, a well-built and cared for example is ultra reliable – always the ace card in the Honda CB playbook. It feels like it would take you across the country tomorrow. Plus it's a smooth and throughly enjoyable ride that you could happily plan to take away on a long trip.

Of the classics in the shed, it’s the one that causes me the least grief and is by far the most lairy. Now, where are the flares and the gold chains? We need to dress up if we’re taking it out for a ride…

***

Honda CB750-Four


Care & feeding

Oil is checked via a tank with a dipstick on the right side – this is a dry-sump engine – and regular changes are important. Both the bottom and top end bearings are plain rather than rollers, making good lubrication essential.

A note of caution when checking the oil: if it's cold and has sat for a while, expect a very low (but still visible) level in the tank. They have a tendency to 'wet sump' a little but, unlike (for example) a Commando of the same period, this isn't a problem. The real level will rise and reveal itself when the bike has run for a few minutes and warmed up. Use the latter to judge whether it needs more.


A CB of this age will be running twin sets of ignition points, so you will need to get familiar with the old-school idea of timing (static or dynamic) and measuring point gaps. It’s not particularly difficult and the skills transfer to many bikes and cars of the era. A workshop manual is very useful.


Access for tappet adjustment is very good and the process very simple. Similarly, access for the spark plugs is also good.

If you're considering a top-end rebuild, be aware that lifting the head is an engine-out job. Not complex, but a bit of a bastard to do. The powerplant is a super-tight squeeze (there's a technique to getting it in and out of the frame) and you're strongly advised to have an extra set of hands to help out.

Parts supply is excellent. Probably the best source in Australia is Pud's Four Parts.

See the 1970 K0 road test from Classic Two Wheels

Identification

Here's a really good ID and restoration resource: honda750expert.com

Honda CB750-Four

SPECS:
Honda CB750-Four K1

ENGINE:

TYPE: Air-cooled, two-valves-per-cylinder, OHC inline four
CAPACITY: 736cc

BORE & STROKE: 61 x 63mm

COMPRESSION RATIO: 9:1

FUEL SYSTEM: 4 x 28mm Keihin carburettors
TRANSMISSION:

TYPE: Five-speed, constant-mesh, 

FINAL DRIVE: chain
CHASSIS & RUNNING GEAR:

FRAME TYPE: twin loop steel
FRONT SUSPENSION: non-adjustable forks
REAR SUSPENSION: FVQ twin shocks, preload adjustment
FRONT BRAKE: single 290mm disc with single-piston caliper
REAR BRAKE: 178mm drum
DIMENSIONS & CAPACITIES:

DRY WEIGHT: 226kg
SEAT HEIGHT: 800mm

WHEELBASE: 1453mm
FUEL CAPACITY: 18.2L

WHEELS & TYRES:
FRONT: 19-inch wire spoke, 3.25-19
REAR: 18-inch wire spoke, 4.00-18

PERFORMANCE:

POWER: 50kW (67hp) @8000rpm
TORQUE: NA
TOP SPEED: 200km/h
STANDING QUARTER: 13.5sec, 160km/h

Honda CB750-Four

Honda CB750-Four


Honda CB750-Four

Honda CB750-Four

Honda CB750-Four

Honda CB750-Four

Honda CB750-Four

Honda CB750-Four

Honda CB750-Four

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