What to look out for?

SERVICE COSTS:

Doing a home service on a CB350 isn’t beyond the average home mechanic, though a set of JIS screwdrivers will come in handy if you don’t want to butcher your screw heads. You might want to change the casing screws for stainless allen bolts (around £20). Oil filters are £7.99, air filters are cleanable, the sump takes two litres of oil (£15-20) and spark plugs are £4 each. Brisk plugs from F2 Motorcycles are worth considering. A new chain and sprocket kit is £40 from M+P, while a decent set of Dunlop K82 tyres will cost £170. You can get cheaper tyres; it all depends on how much your skin is worth.

LUBRICATION:

The original manual lists 10w-40 multigrade for the unit construction engine and gearbox. A good motorcycle semi synthetic oil will be fine. The most important thing to do is change engine oil every 1000 miles and keep the filter clean. Grease the swingarm pivot regularly.

CARBS:

A lot of US and Canadian imports will have been sitting for a long time, so expect gummed up carbs. At the same time those carbs will often have been untouched by human hand, which is a good thing. Take them off, carefully avoiding splitting any rubber parts, dismantle and clean. Ultrasonic cleaning makes them look good and may help but do make sure you clean all the jets. If the previous owner has binned the original air filters, replacements cost £32 from David Silver. The airbox is harder to find.

FRAME AND SUSPENSION

The 350/360 had a mixture of a tubular cradle and a pressed steel top tube hidden by the petrol tank. This stretches back under the seat. Where the lower cradle tubes meet the shock absorber mounts and where the single front down tube meets the cradle are both potential trouble spots, where water can get inside and rot the tubes from the inside out. You cannot lubricate the stand pivot without removing the stand, it seizes and can wear oval. Frames can crack around the swing arm pivot if not looked after. The rear shocks will, if original, be worn out. As they have a forked clamp at the base, replacements are limited, but pattern items and upgrades are available (Wemoto have both period pattern shocks at £78 or Hagons at £148). Forks are basic and replacement stanchions can be found (Wemoto £126.47 each)

EXHAUSTS:

The exhaust downpipes are good, but the silencers rot. Replica silencers for the CB350 models are around £114 from David Silver, but basic pattern pipes will do the job. Original upswept silencers for the CB360 cost £185. The studs holding the pipes into the head will have rusted, so take extra care removing the nuts. The CL exhaust is a different matter. The high-level exhaust changed every year, for a start, and on early models they came with easy rust painted mild steel exhaust boxes behind the heatshields. If you seek originality, make sure the bike you want to buy has decent exhausts. In 1970 Honda gave the CL and CB twin a refresh and the CL’s high-level two-into-one silencer box was replaced by a pair of British sausage-style silencers, which was a more practical and hard-wearing arrangement. Replacements are unobtainable.

ENGINE:

If there’s an issue with the engine, it’s nearly always going to be something to do with the camshaft operation. The camshaft runs in aluminium end caps mounted on either end of the cylinder head. An endless chain (David Silver Spares pattern £25, original £59.95) loops around the crankshaft and cam sprockets. There are two springs per valve and the outer springs are progressive. The cam chain tensioner roller was made of rubber and may well have become brittle and hard. Check the inside of the centrifugal oil filter where bits of crumbling roller will have lodged themselves inside a half-inch sleeve. The roller may need replacing (David Silver Spares £59). The cam end caps, and the cam lobes could also have suffered if the engine didn’t get the specified 1500-mile oil changes. After an increase in capacity to 354cc, a beefed-up crankshaft, revised oil pump and an extra gear, power was down by 2bhp. Although externally similar the 350 and 360 are completely different bikes with few interchangeable parts.

“but Honda clearly didn’t expect users to have serious off-road pretensions as they didn’t bother to fit a bash plate and it had road tyres as standard.”

BODYWORK:

Side panel lugs fracture. That’s one of life’s great lessons, and they will fracture on Honda 350s. Lugs can be plastic welded, and there are various plastic glues that might work. As you don’t want to lose your side panels, attaching them with ratchet ties won’t hurt. Watch out for the light-fingered stealing the expensive and hard-to-find side panel badges. Petrol tanks are made from good quality steel. Seat bases will rot, especially if the seat cover has split, allowing water into the seat foam to reach the metal seat pan. Pattern front mudguards are available if yours are rusty beyond patina. (David Silver £135).

ELECTRICS:

These were pretty good when new but can sometimes need a refresh. The bike came with separate regulator-rectifier set ups. A universal combined Reg/Rec will cost you £59 from Rex’s Speed Shop. Pattern coils and points are easy to find. British Bike Bits will sell you an electronic Boyer system for £189.60. Left-hand switchgear, both original (£59) and pattern (£29), are available from David Silver.

HEADLIGHT:

Like a lot of Seventies Japanese motorcycles, the CB/CL was fitted with a sealed beam headlight. This can be swapped for a superior H4/LED headlight (Paul Goff, £42.90-71.25). Make sure the shell is the right one, as the 360 shell is smaller and replacement reflectors may not fit.

BRAKES:

The drums on the early bikes are good items and don’t require major maintenance. The disc on the last models was a Honda design which uses a swinging pivot, and this can seize up and needs regular attention.