Whilst a family bereavement has caused its fair share of emotional turmoil for Vincent Page and Lesley White over the last week their hard-core Dunlop Maxima rider Neil Berry brought smiles to their faces over the bank holiday weekend taking a very credible 4th place overall in the O.R.P.A. two day British Championship.

The annual two day event takes which place at the Horsham circuit on the Sunday moving to Northchapel for the second days racing on the Monday provided a contrasting mix in terms of weather conditions this year with rider's capabilities being seriously challenged on Sunday with pounding rain and heavy mud. Twenty miles down the road twenty four hours later and the Northchapel paddock awoke to sunshine and superb racing which eventually started throwing up dust. (Typical British weather)

Keeping up with the frantic pace of promotion, Maico International's latest excursion took on a rather emotional tone last weekend when the new Maico M.M.X. shed a few quiet tears as its wheels touched down outside the birth place of its forefathers at Pfaffingen in Germany.

Between them bosses of the U.K. Company Vincent Page and Lesley White share an almost unrivalled passion for the marque and felt it a fitting tribute to let the company's M.M.X. race bike sample its unique background before a wheel is turned in anger this year.

The transmission is a collection of gears that change the revolution ratio of the drive shaft which rotates the rear tire. The input to this system comes from the clutch which is rotated by the crank shaft via a gear driven system or a primary chain. This section I will provide an example of how gears work and this example will be the 1982 Maico 490 GS transmission.

The Maico 490 GS has three shafts in the transmission. The "MainShaft" which is the power input, the main shaft is attached to the clutch and rotates the transmission gears. The "Layshaft" which is the shaft that is rotated by the main shaft and finally the drive shaft which is rotated by the lay shaft. The full sequence of events that occur in the Maico 490 GS are as follows.

Horsepower is generally used to relate how powerful an engine is in relation to the number of horses it would take to equal it's power and is generally stated to be "33,000 foot pounds of work per minute". The horse power output of an engine varies depending on the torque and the RPM of the crankshaft. The formula for computing horse power is HP = ((Torque)*(RPM))/5252. The 5252 is a constant that represents 1 horse power, if Torque (foot pounds) * RPM is 5252 then you have 1 horse power generated as output. This constant is calculated by taking the amount of foot pounds in 1 horse power (33,000) and converting it into radians per revolution (2*PI) so 5252 = 33000/(2*PI). The general equation is "Power = (Force * Distance) / Time" which in this case force is torque in foot pounds, distance is the revolutions per minute of the crank shaft, time is calculated as 1 horsepower in a single revolution and power is in units of "horse power" or 33,000 foot pounds.

Let's take a look at severals specifications for the KTM 495's maximum power output.

The speed at which your tire rotates and the size of your tires determines how fast you are able to move. You can compute the amount of ground your tire would cover in a single rotation by computing the circumference of a circle. PI * Diameter = Circumference so with a tire of 18 inches you would get 3.14 * 18 inches = 56.52 inches or 4.71 feet. This is how far your bike will move after the tire has rotated a full turn.

This can be further used to determine how many times the tire needs to rotate to cover an entire mile. There are 5,280 feet in a mile and your tire coverse 4.71 feet for every rotation so 5,280/4.71 feet = 1,121 rotations of the rear tire covers one mile. Please note that these are just estimates.

Power band is a very controversial word when talking about dirt bikes. It is commonly believed that "power band" was a new concept for some race bikes/dirt bikes and it was a common question "Does this bike have power band?". I remember one time my dad was working on a bike and one of the kids I hung around with asked him what was wrong and he said "I'm putting in a new power band, the old one was worn out". People would talk about "Power Band" as if it was a physical peice of the bike that you could replace.

I remember "Power Band" was explained one time that a normal motor goes up to about 8,000 RPM however a motor with power band (i.e. a race bike) goes up to 12,000 RPM. The "Power Band" kicks in when the motor has reached peak RPM of 8,000 and then it kicks into power band and keeps going beyond the peak RPM to 12,000 RPM. That's a power band!

Changing the front and rear sprockets of a motorcycle has the affect of changing the gear ratio. That means you will either gain more power/torque but lose top end speed or you will lose top end speed but gain more power/torque. The gear ratio is computed by dividing the number of teeth on the rear sprocket by the number of teeth on the front sprocket. This means that for example a motorcycle with a 51 tooth rear sprocket and a 15 tooth front sprocket has a gear ratio of 51/15 = 3.4. You can affect this ratio by changing the number of teeth on either the front sprocket or the rear sprocket. Adding more teeth to the rear sprocket is the same affect as lowering the number of teeth on the front sprocket. The opposite is also true in that lowering the number of teeth on the rear sprocket is the same affect as adding more teeth to the front sprocket.

A 12 tooth front sprocket and a 48 tooth rear sprocket is the same as having a 60 tooth rear sprocket and a 15 tooth front sprocket. Notice the example math below (gear ratios are written as 1:ratio):