Royal Enfield and sidecar are natural combination

The famous 6 hp Royal Enfield and sidecar combination.

Blogger Jorge Pullin has called the Royal Enfield 6-horsepower sidecar combination the motorcycle "for which nothing was impossible."

His My Royal Enfields blog recounts myriad examples of these Royal Enfield outfits of the 19-teens and twenties overcoming obstacles, winning competitions, fighting wars and proving their general utility.

In fact, Royal Enfield was so closely identified with motorcycle sidecars back then that magazine writers reviewing solo Royal Enfields felt compelled to explain that, yes, Royal Enfield would sell you a motorcycle alone.

Recently I was delighted to examine a Royal Enfield and sidecar photographed on a vintage post card. The post card is in the Lang Collection at the Owls Head Transportation Museum in Maine. This Royal Enfield was identified by Richard Miller, who blogs at Red Devil Motors, as a 6 hp model from about 1913.

The post card's circa 1913 Royal Enfield and sidecar were well used by the time of the photo.
(Lang Collection Photo, Owls Head Museum)

Curious about what it must have been like to ride such a machine, I found a slightly later (1917) owner's manual for the 6-horsepower Royal Enfield sidecar combination on the Barnstormers New Zealand website.

This explained much.

For instance, the small protuberance seen poking up above the flat tank just the other side of the top frame rail is the glass dome of the drip-feed lubrication system. The rider — even while in motion! — uses an adjacent valve to adjust the rate of oil flow visible in the glass dome to 30-40 drops per minute.

This so-called "automatic lubrication of the engine" is powered by "suction." So, while the oily glass dome can be unscrewed for cleaning, it must be returned carefully — as "unless all joints are air-tight, the system will not work."

The slightly more sophisticated looking 1917 6 hp Royal Enfield and sidecar.

To my surprise, the manual contains very little about the Royal Enfield sidecar itself. Designed and made by Royal Enfield, and fitted to coupling lugs brazed to the frame when it was formed, the sidecar was apt to give few problems. Apply a bit of furniture polish every so often and you'd be fine.

The motorcycle was more complex. Supplied in either 6 hp (770cc) or 8 hp (965cc) form, the V-twin motors were marked "Enfield" on one side and "JAP" (for J.A. Prestwich and Company, the maker) on the other. Although Royal Enfield did not make the motors, it did recommend its own formula "Royal Enfield motor oil" to lubricate them.

The starting procedure requires adding oil and petrol to the separate compartments of the tank, adjusting various taps and levers, and making sure the two-speed gearbox is in its "free engine" (Neutral, to you) position. Use the oil pump plunger on the tank to give the motor a shot of lubrication before starting. The "extra air lever" is closed for starting. You will open it for normal running.

It is "very important" (I bet it is!) not to advance the ignition lever fully before starting. That's because you are about to grasp the starting crank (not a kick starter — a hand crank) with your delicate right wrist. If this thing kicks back it's going to hurt.

With your left hand you use a handlebar lever to raise the exhaust valves. Now, quickly rotate the starting handle and simultaneously drop the exhaust lever. "The engine should then fire immediately."

Now all you have to do is ride the thing.

Draw the gear lever gently backwards towards low gear, being careful not to stall the motor. As speed picks up push the lever "sharply" forward into high gear. Gradually open the extra air lever as the motor warms.

Control speed with the throttle lever on the handlebars. Don't use the valve lifter to reduce speed, you'll pit the valves! In traffic you will have to put the gear lever in neutral occasionally to shed speed. Probably there wasn't much traffic in 1917?

Mind the lubrication! If you encounter a steep hill you'll need to use the oil pump plunger to give the motor an extra dose of Royal Enfield oil.

Complication: this same pump can send shots of oil to either the motor or to the gearbox. You'd better know to which the oil is going. The tap that controls this is out of sight beneath the tank. Move it forward to oil the motor, backward to oil the gears.

Meanwhile, remember to watch where you are going.

By the way, all this motor oil you're using isn't being automatically recycled back into the tank. It's accumulating in the crankcase and will have to be drained out about every 300 miles. The manual is silent on the question of whether you can then pour the used oil back into the tank. The manual does recommend adding lubricating oil to the tank "through a gauze strainer, so that foreign matter cannot enter."

It's easy to make fun and complain about all the complications of riding a vintage motorcycle. In fact, Royal Enfield had solved many of the problems other motorcycles of the time dished out. Chain drive was far superior to the maintenance hungry belt drives others used. And the "cush drive hub" in the rear wheel (still a feature of Royal Enfields decades later) eliminated "the usual shakes and jars associated with chain drive."

Other conveniences: a tire pump atop the tank, and a detachable rear mudguard to make removing the rear wheel easier.

And here's one trick you wouldn't try today: if you run out of petrol, "endeavor to get a supply of paraffin."

You then lift the front wheel, tilting the machine to the rear so that the very last of the petrol flows into the carburetor and allows the motor to be restarted. Use its heat to warm the paraffin, pour it in, and get going again!

Or, so the manual claims. But, then, it also suggests testing for water in the petrol "by pouring a little of the mixture into the hand, when the petrol will evaporate and the water remain."