Home- Velocity/Engine Speed Programme
- Example
- Tomos - std cylinder and carb
- Tomos - fuel consumption tests
Velocity/Engine Speed Programme - Tomos
The Velocity programme allows the user to either calculate the velocity at a given engine speed or calculate the engine speed for a given velocity for a Tomos .
Top
Example
Suppose you have a Tomos in original condition. Your top speed on the flat is 50 km/hr on 26/22 gearing and the tyres are 2.25" wide. Simply enter this information into the program and select the engine speed radio button. Now enter 50 into the velocity box and hit the Calculate button. The calculated engine speed is 6,848 revs/min.
Tomos - mid 80's model
Shown below is a mid 80's Tomos . This particular bike is 100 % original bar the fitment of a Torqsoft design exhaust system.
The design brief for this pipe was to obtain the same top speed as the std pipe - 50 km/hr - but to have better hill climbing ability, particularly on the steeper hills. The hill climbing velocity for the steep test hill increased from 16 mph(25 km/h) for the std pipe to 22 mph(35 km/h) with the new Torqsoft pipe.
Shown below is the measured power(hp) vs road speed(mph) at the rear wheel for standard pipe vs Torqsoft pipe. The power has increased from 1.65 hp to 2.6 hp, an increase of 62 %. It can also be seen that the acceleration has improved considerably as has the overev power. At 30 mph(48 km/hr) the standard pipe gives 0.8 hp vs 1.45 hp for the Torqsoft pipe.
Tomos - fuel consumption tests
The table below shows the measured fuel consumption - in both mpg (imperial) and l/100km - for a Tomos at different throttle settings. The test course was 30.4 km long over undulating terrain. Fully kitted inc helmet etc, the test rider weighed 77 kg.
The optimum throttle position was found to be 1/2 throttle, resulting in a fuel consumption of 1.85 l/100km (153 mpg imp).
| Throttle | Consumption | ||
|---|---|---|---|
| Gearing | MPG | l/100km | |
| 1/2 throttle | 16/45 | 153 | 1.85 |
| 3/4 throttle | 16/45 | 144 | 1.96 |
| full throttle | 16/45 | 136 | 2.07 |
The table below shows the Port Durations for this totally original engine. The cylinder has open transfers - of which there are two off. It is immediately apparent that the port timings are very mild.
| Port | Duration (deg) | |
|---|---|---|
| Exhaust | 134.6 | |
| Transfer | 90 | |
| Inlet | 120 | |