Honda CB750

1969–1978

The bike that invented the modern superbike — reliable, easy to live with, and still one of the friendliest routes into classic ownership.

Honda CB750

Overview

Engine
736cc air-cooled SOHC inline-four, 2 valves/cylinder, 61mm x 63mm bore/stroke, 4x Keihin CV carburettors, electric start with kickstart backup
Power
67bhp @ 8000rpm (K0/K1) — later years vary, see known_issues
Torque
Unknown
Transmission
5-speed, chain final drive
Frame
Steel tube cradle
Suspension (front)
Unknown
Suspension (rear)
Unknown
Brakes (front)
Single disc (a production-bike first in 1969)
Brakes (rear)
Drum through K6; some F-series got a rear disc
Tyres (front)
Unknown
Tyres (rear)
Unknown
Weight (dry)
218kg (K0)
Weight (wet)
233kg (K0)
Seat height
Unknown
Fuel capacity
Unknown
Top speed
125mph (201km/h) claimed, K0

Price guide

good
£2,000.00–£4,500.00
rough
£1,000.00–£2,000.00
excellent
£4,500.00–£7,000.00
sandcast_k0
£12,000.00–£15,000.00

Known issues

  • Cam chain tensioner wear (Check)

    The automatic tensioner's rubber-faced blades and roller perish with age and aren't available new from Honda. Listen for a rattle from the timing chest on a cold start that doesn't fully quiet once warm — this is a very common, expected fix on a bike this age, not by itself a reason to walk away.

  • Carburettor synchronisation and gumming (Info)

    The four CV carbs need periodic balancing, and modern ethanol fuel left sitting gums up jets and perishes diaphragms. Rough running or hard starting after long storage is usually this rather than anything structural — budget for a strip-and-clean if it's been standing.

  • Frame/engine numbers and sandcast authenticity (Check)

    A genuine early-1969 "sandcast" K0 (rougher, more porous-looking crankcase castings from the first ~7,400 or so built) commands a big premium over a later die-cast K0. TODO(verify) exact sandcast production cut-off/number. Cross-check frame and engine numbers against known K0 ranges before paying a sandcast price.

  • Front brake caliper seizure (Check)

    The single-piston front caliper corrodes internally if the fluid hasn't been changed regularly, and the piston can stick or seize. Check the caliper slides freely, the lever has a firm bite, and the disc isn't scored or blued from a dragging pad.

  • K2 (1972) is a detuned engine (Info)

    1972-model-year K2 bikes got smaller carb jets, a milder cam, and a more restrictive silencer, dropping rear-wheel power from around 67bhp to roughly 58bhp. Not a fault, but worth knowing if you're cross-shopping different model years on power alone.

  • Metal debris in the oil or on the sump plug (Dealbreaker)

    If the seller can't explain flake on the magnetic sump plug or in a cut-open oil filter, treat it as a red flag — it usually means a cam chain tensioner failed some time ago and has already chewed the chain guides, sprockets, or camshaft.

  • Oil weeping from points cover or head gasket (Info)

    Light seepage around the points cover, cylinder head joint, or output shaft seal is common on an unrestored engine and isn't automatically a red flag — but price a heavy drip into any offer.

  • Selenium rectifier and charging system (Check)

    The original selenium rectifier degrades with age and undercharges the battery. With the engine running above idle, battery voltage should sit around 14-14.5V — a lot lower than that points to a tired rectifier or stator.

  • Wiring harness connector corrosion (Check)

    The multi-pin connector block behind the left side panel is a known weak point: corrosion raises resistance there, and the block can get hot enough to melt. Check for browned or deformed plastic and that the connectors still click together firmly.

Upgrades

History

The CB750 is the bike that invented the word "superbike." Before 1969, a fast road motorcycle meant a British twin that vibrated, leaked, and needed the points reset every other weekend. Honda answered with an air-cooled, electric-start, 736cc inline-four making a genuine 125mph, wrapped around the first front disc brake fitted to a production motorcycle. It reset what buyers expected from a mass-produced bike, and half a century on it's still one of the most usable classics you can put on the road: parts support is excellent, the engine is a known quantity, and there's a huge community of owners who've already solved every problem you're about to have.

Which CB750 is which

Honda badged each model year with a "K" number. K0 covers the original 1969 bike, running through to K8 in 1978, alongside the sportier CB750F "Supersport" (from 1975) and the semi-automatic CB750A "Hondamatic" (from 1976). For most buyers it's the K-series you want.

The first few thousand K0s — built before Honda's die-casting tooling was ready — used sand-cast crankcases, identifiable by a rougher, more porous-looking finish than later engines. These "sandcast" bikes are the most collectible CB750s in existence and are priced accordingly; if a seller is asking sandcast money, get the frame and engine numbers checked against Honda's known K0 ranges before you agree anything — Honda built 7,414 sandcast units (frame/engine numbers CB750-1000001 to CB750-1007414) before switching to die-cast cases.

1972's K2 is worth knowing about specifically: Honda detuned the engine that year — smaller carb jets, a milder cam, a more restrictive silencer — dropping power from around 67bhp to roughly 58bhp. It's not a fault, and K2s are otherwise good, honest bikes, but don't be surprised if one feels noticeably softer than a K0/K1 or K3 on the same road.

By K6 (1975) and K7 (1977) the bike had matured: fettled electrics, a stiffer frame, and in the K7's case a fairly thorough overhaul while keeping the classic four-pipe look. They're also, not coincidentally, the best value entry point into CB750 ownership.

What to check when buying, common upgrades, and UK prices now live in their own sections on this page, below — see Known issues, Upgrades, and Price guide.

Sources

If anything on this page is believed incorrect, please let us know and we will update it accordingly.