Whoops, ran out of petrol

[nuttycyclist]

I found myself with a Sunday free, so had a great day on the motorbike pootling around the Kent country lanes and looking at the villages.  After calling in on Kathy I then had a good motorway blat home.

I haven't ridden slowly on the bike in ages, it's been mostly motorway commuting, but I did enjoy the 20 or 30mph pottering and admiring the view.  I think I puzzled some walkers when they heard the bike, stepped ot one side, then had a long wait while I trundled towards them at 15 to 20mph.


Trouble was on the dual carriageway coming home    There I was at 70mph passing traffic and with a car up me chuff when the bike started losing power.  Initial thought was "petrol" followed by shouldn't be I've only done 170 miles and usually get at least 185 before refuelling.

But yes, after reaching down for the fuel tap and turning it to reserve (and no doubt confusing the driver I was in the process of passing when I slowed down, and annoying the driver I was holding up more and more), the bike picked up and I managed the last 10 miles home.



I must remember that I need to ride faster to be more fuel efficient in future.  No more going slow for me.   

The car has a computer that shows the fuel efficiency and I've posted on here before that the car runs better at 80mph (as per the 130kmh speed limits in Europe) than at 70mph here where it is geared wrong.  Looks like the same is true of the motorbike.

[Kathy]

Looks like the same is true of the motorbike.

Or we gave you too much food before you went home and increased the load on your poor little bike. 

No more banana muffins for you!

[tatanab]

turning it to reserve

About 10 years ago I was on the M4 riding a BMW R80 (hated the damned thing).  I'd forgotten that I'd put it on reserve the day before and duly spluttered to a halt on the hard shoulder.  I thought "oh poo, now what".  Then I remembered that this machine had all the fuel from one tap on the left of the tank, but it was a pannier tank and so there was probably a pint trapped on the right hand side.  I laid the bike on the ground and prodded it and shook it enough to get some fuel to fall into the left, enough for the 10 miles or so to a petrol station.

[Moloko]

I've only done 170 miles and usually get at least 185 before refuelling.

Your sister sneakily siphoned some off for "fire breathing" high jinks after you'd gone.

[Kathy]

I've only done 170 miles and usually get at least 185 before refuelling.

Your sister sneakily siphoned some off for "fire breathing" high jinks after you'd gone.

 

No way! Pyromaniac fool I may be, but even I ain't mad enough to try fire breathing petrol!

(Too volatile - the vapour stream tends to ignite and track back and blow your lower jaw off).

[rogerzilla]

There's an optimum speed for efficiency where the sum of heat losses from the engine* and power required to overcome air resistance reach a minimum, usually about 40mph for a car.  For a motorbike it's probably a higher speed, since the engine is (I imagine) less efficient.


*a rule of thumb is that, for a really efficient diesel engine, you get 1/3 of the fuel as useful work, 1/3 goes to the radiator as heat and 1/3 goes out of the exhaust as heat.

[Jaded]

and what about the other 1/3? 

[rogerzilla]

Is it like project management, where the first 90% of the project takes 90% of the time, and the remaining 10% of the project takes the other 90% of the time?