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RIDING AN EARLY BIKE #3: “Bodies in Motion”

May 1, 2010

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The author riding on Hwy 1.  Photo by Conrad Leach.

While underway, fiddling with controls will eventually bring the motor bicycle to a speed that IT is happy with. This may or may not be the speed that YOU would prefer for the terrain ahead. Like Newton’s 1st law states: “Bodies in motion tend to stay in motion.” The bike won’t accelerate with a surge of power, nor will it stop on a dime. They also do not turn with the roadholding ability of later bikes. Generally speaking, the older the bike, the less variety of speeds that the motor will comfortably pull. If you mentally settle down and enjoy whatever pace you are travelling at, you will soon notice that you enjoy that speed.

crashed ExcelsiorSometimes things don’t go right.  Photo by Richard Morris.

Breakdowns were common-1

Breakdowns are common, and vary from minor issues to catastrophic mechanical mayhem. But when they are going, there is no matching the fun of riding an early bike. The number of smiles per mile cannot be matched by any late model bike.

 

premier con rod bushing While tootling along, don’t forget that there is no automatic oiling for the motor. The rider must pump oil into the motor every few miles, or else bad things will happen. Here is a pic of the big end bushing on my Premier, after a long ride up a steep hill at high rpms, with not quite enough oil. The new big end bushing is in place, and the broken up old one is on the right. It seized up solid onto the crankshaft, and there was no more riding for me until the entire motor came apart and a new bushing was made…  😦

 

Riding a direct drive bike (no clutch) is a different experience that is hard to describe. You cannot stop the bike if you come across traffic or a stop light, without the motor coming to a stop. So the rider tries to avoid any stops, by whatever means necessary. But while underway, there is little to trouble the rider. No gear changes to contemplate, no clutches to engage or slip. Just set the throttle and timing and enjoy.

Belt drive bikes are peacefully quiet while underway, as the belt gently pulls the rear wheel pulley around and around, taking up any shocks that the motor gives out during its 4 stroke pulses. Bike designers didn’t start using engine drive shaft shock absorbers until chain drive became common. The chains transmitted the motor’s power pulses every 4th stroke right through the chassis, and riders complained. Many writers and riders in 1910 through the Great War thought that belt drives would be the de facto method of power transmission, so strong were the rider’s complaints of the harsh chain drives. Chains and engine shock absorbers did dominate from 1925 onward, due to their resistance to slipping in wet or oily conditions, plus their ability to fit around small diameter drive sprockets and clutch wheels. But recently, highly engineered belts have been used for primary and final drives, not due to their quietness or shock-absorbing qualities, but because they do not need to be adjusted or replaced often as chains do.

 

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Writers often wax poetic about riding a belt drive bike, referencing the quiet simplicity of days gone by. A common phrase is that “when riding a belt drive bike, all you hear is the chuff, chuff of the motor and the click, click of the belt fastener as it goes around the engine pulley” –As opposed the whirr of chains and throaty exhausts of later bikes. But the fastener should only click if it things are set up wrong. Correctly set up fasteners and pulleys do not allow the hardware to touch the pulleys, only the belt.

 

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DOUBLE CLUTCHING

Hopefully your Dad taught you how to double clutch. But if he didn’t, here is a short primer on it: When you have disengaged the clutch and are shifting up a gear, close the throttle slightly. When shifting down, open the throttle a bit. That’s it.

It will take some practice, but you will be rewarded with much smoother shifts, less noise and damage from the gearbox, and less missed shifts or false neutrals and less wear on the clutch material.

 

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That is the HOW of double clutching, the WHY is a bit more complicated… Early gearboxes had somewhat primitive dogs that engaged as the shifter was thrown from one position to the next. Shown in the image above, the dogs are labeled E1.  The gear labeled D slides to the left and the dogs engage with the gear F.  Think of it like the little teeth on two checkerboard pieces. As they spin next to each other at different speeds, it can be tough to engage them. But double clutching will help match the motor speed (through your use of the throttle) to the gearbox speed (dictated by the spinning rear wheel on the ground). As the clutch is disengaged, you can speed up one side of the gearbox to be at the same speed as the mating half of the gearbox. That allows the dog teeth to more easily slide into mesh.

 

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 In this photo from Victor Page, the relevant parts are labeled as Jaw Clutches.  You can see that they will mesh with their gears with very abrupt square shoulders.  Matching the speeds of the Drive gear and the Jaw clutch will allow the parts to mesh without damage.  This in an Indian 2 speed, circa 1913.

Another phrase that is used to describe double clutching is “matching the road speed”.

 

 

 

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Photo from Jeff Clew                                        Worn Burman internal dogs, quantity 21.

 

Now that things are sorted, you can get down the road. 

c1903 Rex

c1903 Rex and wicker sidecar.  photographer unknown.

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