What mpg can I get from
a classic British bike?
Mileage | Miles per gallon | Fuel economy | Triumph | Norton | BSA | Royal Enfield
Broadly speaking, classic OHV British bikes are fairly good on fuel, but are less so for sidevalves. Our old 500cc BSA M20, for instance, never returns more than 40mpg (Imperial), and sometimes as low as 35mpg—and the old Amal 276 carburettor probably leaks half as much as it drinks (such is the fun of British biking).
Sidevalves have notoriously inefficient induction pathways which leads to poor gas flow and overheating; hence fairly regular exhaust valve therapy (although well-fettled examples can carry on happily for tens of thousands of miles without more than basic servicing).
Tip: keep sidevalve ignitions as advanced as possible after start-up retardation.
Meanwhile our 650cc and 750cc OHV Triumphs both return a minimum of 50mpg, and sometimes as much as 60mpg. Or thereabouts. Easy cruising on the six-fifty gets us up to 65mpg. But if you're riding it that easy, you might not be enjoying your ride as much as possible.
Single-carbed twins (Triumph 650cc/750cc Tigers) are, naturally, always slightly better on fuel than twin-carbed twins. High performance Brit bikes are typically worse on fuel—but by no means always. A sorted, balanced, lightened and gas-flowed high performance engine can be very economical. It's just that owners tend to ride harder and faster.
Our old BSA A10 Golden Flash meanwhile is good for around 45 - 55mpg. It never seems to return more or less no matter how hard or how gently it's ridden. Our 250cc Triumph TR25W is good for maybe 70 - 75mpg. Well, a comfortable 65mpg anyway.
A 500cc Triumph 5TA, or a BSA A50, or Norton 600 Dominator should all return 55 - 60mpg upward. But around 70mpg for the 5TA isn't unheard of. And even 80mpg gets talked about by some owners (but we've never quite seen such numbers from a 500cc twin).
With careful riding, Royal Enfield 350 singles will return around 80mpg. Carburetted 500 Enfield singles will get a comfortable 65 - 70mpg—and even a little more for fuel-injected versions.
A 200cc Triumph Tiger Cub, meanwhile, should return around 80 - 90mpg.
Two-stroke British bikes generally return anything from around 70 - 80mpg (125cc BSA Bantam), but you'll have to factor in oil costs. And you'll get a similar mpg figure for a 250c Ariel Arrow or Leader.
750cc Triumph Tridents or BSA Rocket 3s are poor on fuel (but great fun to ride if you lean on 'em a little, or a lot). You can expect 40mpg, give or take 5mpg depending on how you ride it and what kind of load you're carrying.
1,000cc Vincent twins are good for around 46mpg on a good day (a little less perhaps on harder riding). And you won't get much more from a single cylinder Vincent (500cc Comet).
Any Ariel Square Four (600cc - 1,000cc) will return 40mpg, and you'll get another 5mpg from the best of them. A 500cc Sunbeam S7 or S8 will return around 50mpg. But as corny as it sounds (and it does sound pretty corny), classic bikes are all about smiles per gallon, not miles per gallon. Come to think of it, that's what all motorcycles ought to be about, isn't it?
Remember to look at our Motorcycle Buyers Guide pages too. We have plenty of tips and advice there with a huge range of bikes to discover or rediscover.
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