Setting up the engine for long range minimal maintenance running.

Re the generic cheap **** Chinese made 48cc, 2 stroke engine.

Just curious:

a) In Australia we have a 200W limit on the engines under 50cc... just wondering what kind of distance you get per liter, at 200W output.

In terms of setting up the engine for longevity... with an oiled air filter and proper allen key bolts, with thread locking compound, etc., etc., etc...

b) The clutch is a dry clutch, coated with a little grease on the hubs teeth, to lubricate this and the connecting engine gear. Me thinks, make an oil bath lubrication of the clutch gear. I'd rather ask this first, before I have to soak the clutch friction pads in solvent to remove the oil - but has anyone ever put half a cup of thin motor oil in the clutch housing, to lubricate the gears inside it - and has this affected the clutches ability to grip it's plates? Do they grip or do they slip?

(Most real motorcycles all use wet clutches in an oil bath...)

Mmm K.

See Americans think that the rest of the world uses their standard...

Americans are only 5% of the worlds population.

The rest of the world uses metric - Kilometers per liter, and I don't know if you are actually English or American - the Brits gallon is 4.5 liters and the Americans gallon is 4.25 liters....

And distance is 1.6Km per mile....

biknut said:

I got 145 mpg with my Flying Horse 48cc motor, running a 40T sprocket, and cruising about 26 mph. I think it had a 66 jet in the NT.

Click to expand...

Assuming your in the USA, with the US liquid gallon of 3.78 Liters per gallon, vs. the British Imperial gallon of 4.55 liters.

So 145 MPG = 235Km per 3.78 Litres = 61.4 Km/L travelling at 41Kmh.


In the UK - with the Imperial Gallon........

145 MPG = 235Km per 4.5 Litres = 51Km/L travelling at 41Kmh.



I wonder what that would be on a derated engine, travelling at say 25Kmh?

For instance, doubiling your speed = multiplying your fuel consumption (=power) by the cube. It takes 8 tiumes as much power to travel at 100Kmh as it does to travel at 50Kmh.

Foir instance, travelling at 50Kmh will use 1/8th the amount of power as travelling at 100Km, but you will also be travelling for TWICE as long.

So to back calculate from 45Kmhh to 25Kmh.... and to get the fuel consumption mathematically from this - excluding relative effiencies of the drive train (rolling resistance / chains and bearings and seals etc), the cross sectional area or CD of the rider, the load and the bike etc... (wind resistance)

61Km/l / 8 = 7.62 x 25 = 192Km/l - the fuel consumption at 25Kmh

It will take 1.8 times as long to travel a given distance at 25Kmh as it does at 45Kmh (45/25=1.8)

So therefore 192Km per liter will take 4.27 hours to cover the 192Km

At 25Kmh it will take 7.68 hours to cover the 192Km

Damn......


The power required to overcome the aerodynamic drag is given by:

P_d = \mathbf{F}_d \cdot \mathbf{v} = {1 \over 2} \rho v^3 A C_d

Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power.



So yes the limitations of legislation..... and the 200W engine restriction.

Dammit.

I am using the engine to "assist" with towing large loads over long distances...

The statuatory limit is it must not be capable of exceeding 200W in power which is about 25Kmh on a flat road.

The engine has a claimed 1200W @ 5500RPM.

I will gear it for 200W @ 4000 RPM @ 25Kmh - I will do that by making up my own auxilliary (secondary) carburettor - since it's not much more than a hefty idle - in terms of output.

The main carb will be lawfully used only for OFF road purposes because the fines etc., are pretty draconian where I live...

By off road I mean, very strong head winds or steep inclines - off road....

maniac57 said:

How do they measure your engine output?
Where the heck do you live dude?
Me? I'd simply make some fake documentation and dare any cop to prove different.

Click to expand...

The cops might have too much free time on their hands and they can also test them...

You need to spend time doing court work and reverse engineering / forensic investigation.

The simple test is to hop on the damned thing and open the throttle right up and if it goes sailing through 25Kmh - up to 40Kmh = you busted.

Unregisterd motorcycle.

Uninsured motorcycle.

Unroadworthy motorcycle.

Etc.

And if your involved in a crash....

IN Australia the issue is "Pedal Assist" - what a reasonably fit (????) person can do in a cozy going to the shops / commmuting kind of a speed and power output.


While I techhnically agree with the 200W limit - as it is all within the capability of the bike to handle it, I kind of grate at the idea of people using engines stuck on trailers that have 3 - 6 HP - and can cruise at 60Kmh...

And they can, and I can't. (legally)

I have LONG distances to cover with BIG loads....

And I think well...... "A 200Km round trip once a month, in one day.... while I sure appreciate the great out doors - at 25Kmh, that is going to take a long time and peddalling for 10 hours is not really my cup of tea..........."

40Kmh sounds like a good speed.....

But I suppose there is almost abandoned back roads, the legal engine pulling the trailer and the "spare emergency engine" inside it.

Naaaa just run twin carburettors, the SMALL one for all time running, under the legal 200W and 25Kmh, and the big one for those times where there are really strong head winds, big hills and huge loads on the trailer.

Basically to get busted, you have to be seen to be NOT pedalling, and going up a hill at 35Kmh...

I live in an area where there are wide open plains, and sometimes the prevailing head winds are 30 - 40, 50 - 60Kmh...

It's just way too much to be able to even pedal into them, when they are strong and there is like 100Km of them - and a trailer on the back.


So the little bit of extra assitance just to maintain a legal road speed - could be factored in.

Adding in a second 6.5Hp engine into the trailer, seriously derated, and running at a fast idle, with deep reduction gearing to help with the heavy loads - as well as being necessary at times, will also be a spare engine, if the 2 stroke conks out.

It's hard to haul 100 - 200Kg of gear 100Km over mildly hilly terrain into strong head winds.