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I figured to post up here too, just in case anyone doesn't frequent the K440 Cars Bikes section.


Anyway, I'm heading to Kampong Cham in a few weeks, and the goal is to build a scooter that will get me there from Phnom Penh on 1 litre of fuel, which equals 353 mpg or 0.8L/100km.



The bike in question is a Honda Giorcub (not a Super Cub), 4 speed clutched manual full faring scooter. It features a 49cc, 3.5 horsepower engine and 0-100 time of impossible, top speed of 55 kph.



As of now, (this is my second one of these), I've managed to top out at "just" 70 km/l (190 mpg or 1.4L/100) but it think it can do better with a little tinkering. To be honest though, I have no idea if it's even possible, and this build is more shooting for the stars than anything.

Wanting to see what you all think (or if you care ) and if you think it's possible.

I'll be making the ride in a few weeks, building up the scooter in the meantime on this thread.


So far here are the preliminary build steps of the scooter. Engine is apart.

Alright, cracked open the motor and found a few areas where I can save on some internal friction.




Cases...



Firstly, big drive bearings that I suspect it had. I know bearings are bearings, nearly eliminating all friction in the first place, but the smaller the surface area, the lower the friction. Small gains, probably not worth it, too late bought the parts already...



Located some small cases for it.




Drive bearing size comparison.






Carburetor on these beast seems to flow well...maybe a little too well.




I think restricting it with a mini carb would help...




As would putting on a cylinder head with pea sized valves and ports.






Looks like there's some gains to be had at the expense of a little power. I'm guess I'll end up with a 2 3/4 horsepower machine when I'm done,


Have fun reading
-Akira

Can you add another choice to the poll? "Yes, under the right conditions."

Great idea! If you make it, get the newspapers to report on it.

^^I've been in U.S. and Japanese local news for hypermiling events and there's never any interest from the public usually. One of "our guys" did 30 mpg in a V8 Ford F-350 and the general response was "Fff, I'm not going to drive nicely to save on fuel..."

UT, that's just a "Yes" then?

you can do it boss, we have faith in you bro!

Got an engine cobbled together today:


Small port/valve cylinder head, small bearing cases, small oil pump, small final drive gear and small carb, but still kept the original 8.8:1 CR piston. 10W-40 oil. Standard rocker arms because I couldn't find rollers available for a 50.

Power is SEVERELY DIMINISHED

Preliminary runs have me sitting at 84 km/l (237 mpg, 1.19L/100km).

I haven't got the jetting right yet and it's running a tad rich, and the spark plug is one degree too hot, but I'm sort of doubting that jetting is going to find me the extra 40 km/l I need, so I'm now looking at a higher compression setup already and some more drastic engine measures.






To be continued.

Well that was boring.

127.7 km/l (361 mpg or .783L/100km) over a 1 hour ride today, GPS verified.

Backed off two sizes on the jetting, colder plug, thinner oil (SAE 30), pumped up tyres to 45 psi and cruised up the country side roads. Got stopped by the police even, but had docs in order and all was well. They found the external petrol bottle amusing.

I guess this wont be so much a "will I make it?", but how far can I go on how little. I guess I'll need to make a new poll or something.

Interesting that on this forum you have 3 Positive votes and 3 Negative votes.
OTOF it's all negative. 8 'No' votes.

I wonder if any of them change their tune after this latest information.

AE86 is the Gandalf of two-strokes.

Thou shall not pass me at 35kmh

Username Taken wrote:Interesting that on this forum you have 3 Positive votes and 3 Negative votes.
OTOF it's all negative. 8 'No' votes.

I wonder if any of them change their tune after this latest information.

I haven't been able to log in for the last two or three days, I keep getting a "Server Unexpectedly Dropped Connection", so I have no way to update over there. Not sure why though, here is fine, as is everywhere else.

The results were a bit of a surprise to me though. I wasn't expecting much passed 100 km/l with luck on my side, so to break 125 already kind of took the fun out of this whole challenge.

Tadpole wrote:AE86 is the Gandalf of two-strokes.

It's a 4 stroke though.

I'm a "Fool of a Took" when it comes to 2 strokes, therefore I stick 4 strokes.



Anyway, thinking of what next to aim for. Anything over the goal is just fluff, which seems kind of boring now.