Thursday, July 14, 2016

Japanese Vintage Motor Cycle Suzuki GP 100 dimensions explained!

This blog provides kind of insight into my earlier blog post on the dimensions of my dad’s Suzuki GP 100. Readers came up with interesting technical questions and I would try my best to answer them, in a simple way.

Overall length, width and height of a motor cycle are not that hard to understand. Imagine the GP 100 as a wooden bench in your room. There is an overall length, width and height for that too. Got the point? Apply the same to GP 100 and you are okay.

Now, the wheelbase. Yeah. Take a look at the front and rear wheels of a motor bike. There are center points on each wheel. At each center point, there is an axle. Good. The distance between those front and rear axles is called the wheelbase. It is a sort of length.

Ground clearance. Ignore the wheels. Now what is the lowest point of a motor cycle’s underside? How high it is from ground level? Five inches? Seven inches? That is the ground clearance.

Seat height? Simple. You sit on a motor cycle and try to balance the machine between your legs. Are both your feet flat on the ground? Or is it difficult for your toes to reach the ground? That’s it. This all depends on how high your seat is above ground level. So the distance from ground to the top of the cushions represents Seat height.

Dry mass. Fine. A motor cycle needs fuel to keep it going. For the proper functioning of its mechanism engine oil and transmission oil levels should be duly maintained. Now exclude all this. Imagine the bike has only just rolled out from the production line. You weigh the machine at that precise moment and you get the dry mass of it.

Torque and horse power. Picture yourself paddling a push-bike. You put force on the paddle to keep it going. Where do you apply force? On the paddle. What happens then? The paddle turns a spike wheel that is coupled to the rear wheel. Right. Now, when you apply force to the paddle so that it turns, then there exists something called ‘torque’ there.

This same thing happens inside motor cycle engines. But the part you did when you were paddling a push-bike is now taken up by a piston. Force is applied on this piston when the engine burns petrol. (I am trying to be very simple, so I may sound off hand sometimes. However, my objective is that you understand this).

The piston then turns a crankshaft. Again there is a ‘torque’ here. That is; a force that turns something in a circular motion around a central point, transmitting energy. It is measured in Newton-meters, normally. Suzuki GP 100 torque is 10 Nm.

Okay we came to energy. The rate of transferring energy is power. It is measured in horsepower. This term is said to be used by James Watt when he invented the Steam Engine and explained its performance compared to the power of horses. It is now a unit of measurement for power.  

A Suzuki GP 100 motor cycle’s power is measures 12 HP.
Right. In this post we discussed the overall dimensions of a Suzuki GP 100 motorcycle in a simple way so you can understand these terms without much hassle. Then we explained the basic idea of torque and horse power of the GP 100.

We believe this post would greatly help readers who interested in Suzuki GP 100, specially the collectors of vintage Japanese bikes to get their bearings of the machine in more detailed, yet simplified manner. Meet you in the next blog!

Monday, July 11, 2016

GP100U specifications

To my surprise this bike has attracted lot of interest from collectors worldwide. All of them are full of admiration about the excellent mint condition of the GP100, although it is now more than three decades old. 

For their benefit and all future readers I am publishing a detailed summary (the link would take you to the origianl manuscript published by Suzuki Motors in 1980s) of the specifications of the bike. The technical terms I would explain in my next post. 

Overall length 1900mm (74.8 in)
Overall width 750mm (29.5 in)
Overall height 1045mm (41.1 in)
Wheelbase 1225mm (48.2 in)
Ground clearance 145mm (5.7 in)
Seat height 770mm (30.3 in)
Dry mass (weight) 89 kg (196 lbs)

Maximum horsepower 9.0 kW (12 HP) at 8500 r/min (SAE, NET)
Maximum torque 10.0 Nm (1.04 kg-m 7.5 lb-ft at 8000 r/mn)

Type - Two-stroke cycle, air-cooled
Intake system – Rotary disc valve
Bore 50mm (1.969 in)
Stroke  50mm (1.969 in)
Piston displacement 98cm3 (60 cu. in)
Corrected compression ratio 6.8 : 1
Carburetor - MIKUNI VM22SS single
Air cleaner - Polyurethane foam element
Starter system - Primary kick
Lubrication system - Suzuki ‘CCI’

Clutch -Wet multi-plate type
Transmission - 5 speed constant mesh
Gearshift pattern 1 down, 4 up

Front suspension – Telescopic, oil, dampened
Rear suspension – Swinging, oil, dampened, spring 5-way adjustable
Front brake – internal expanding
Rear brake - internal expanding
Front tyre size – 2.50 18-RP
Rear tyre size – 2.75 18-RP


Fuel Tank including reserve 9.8 liter / (2.61 / 2.2 US/Imp gal)

Tuesday, May 3, 2016

A Scrap of Paper

Last weekend I went home with my wife to see my parents - again. Whenever I get a break I make sure to pay them a visit. Over a cup of tea I asked dad if he has any document relating to this bike he owned for more than three decades. After reflecting a bit, he went to his study and brought out a worn out cardboard folder.

We both went through its contents carefully. My wife and my mom looked on. Most of the documents dealt with his painstaking maintenance work on that bike. No wonder it always looked ready for Grand Prix. Suddenly this poster caught my eye. Very eye catching indeed! My wife and mother both left the living room.

This was how the description ran:

Get the most out of riding!

   The best is now better inside and out!

The GP100U / 125U – It’s the perky bike that is gracing hundreds of city streets. Riders in a wide range of countries have chosen it for its acknowledged quality, performance and riding ease. With its sensitive response and light but durable construction, the GP 100U / 125U gives you the optimum precision handling, carrying you along in comfort and confident style. Going to work, going to school, for errands or even for touring, this on-road machine will give you the performance you want.

Wednesday, April 27, 2016

A Childhood Memory

Since the beginning of my early childhood years I was always in awe of this slim, dragon-fly like monster. Dad would roll it out majestically on to the lawn and after thoughtfully releasing the choke, kick start the beast every morning.

It would wake up immediately with a mighty snarl, reluctantly simmering down to a steady purr as dad tightened his grip on it, a bluish exhaust escaping its nostrils from the rear; a signal of healthy obedience.

As for myself, I would be dressed in my school uniform and lifted and placed on the petrol tank, and mom would straddle the back seat. When we are all comfortably set, dad would rev up the engine and we would be off, all three of us, to our respective destinations.

When I grew up I replaced mom. When I got to high school, I replaced dad also– well, occasionally.

He had purchased this sleek Suzuki GP 100 in 1981 for a price that would be little more than 100 US Dollars nowadays.  Looking back now after 35 years (I am in 2016 now, goodness me) it is hard to imagine how carefully he had kept that brute of a machine, sleek as ever, its threatening growl that is full of character, same as ever.

In weekends I go home with my wife to visit my parents in the countryside, and each time dad rides it (he still does though he is nearing seventy), the GP 100 proudly lives up to its name as of old. Yeah, Grand Prix.