The engine that powers the world

[DomP]

Just watching this on BBC4 about the dominance of the diesel engine and it's made me wonder why diesel bikes haven't taken off. Is it a weight issue?

[SV650rules]

Originally Posted by DomP

Just watching this on BBC4 about the dominance of the diesel engine and it's made me wonder why diesel bikes haven't taken off. Is it a weight issue?

It's weight and engine size and complication - same reason diesel aircraft literally did not take off. Petrol engines produce more power than diesels as well (just look at F1) . Diesels do have a limited rev ranges as well, mainly due to the long stroke that is required to achieve 25:1 and greater compression ratio needed to have compression ignition. personally I am glad dirty diesels never made it into bikes, one of the reasons is that you could find yourself sliding off the road on one of your own fuel spills. Diesels are for tractors and HGV.

Diesels also produce horrible pulses that will destroy the gearbox and transmission, the answer was to have dual mass flywheel, a collection of sliding plates and springs held together with fairy dust that fail on a regular basis and cost lots of money to fix.

[DomP]

Ah yes good points, I've been looking at vans and I'm really put off the idea because of all the horrible stories of expensive failures of modern diesels. Seems to me what made diesels great was their reliabilty/simplicity but that has turned on its head with modern efficiency advances

[SV650rules]

Originally Posted by DomP

Ah yes good points, I've been looking at vans and I'm really put off the idea because of all the horrible stories of expensive failures of modern diesels. Seems to me what made diesels great was their reliabilty/simplicity but that has turned on its head with modern efficiency advances

It is actually mainly the controls and stuff that have been fitted to Diesels to try to control (unsuccessfully) their filthy exhaust that have made them unreliable and expensive to fix.

I think of power as torque x revs (or the size of the bang x the number of bangs per minute) diesels have long stroke (big diameter heavy crank) and limited rev range (not much over 4K for most of them) - petrol has a smaller torque but much higher rev range (most petrol cars will rev to 7K or more now, and as for bikes well we know that they go well over 10K). People get used to the low down torque of a diesel and mistake it for power.

Diesels are gonna find themselves banned from more and more city centres in coming years because of NOX (oxides of nitrogen) and particulates which cause smog and also kill people, buy a diesel today and in a year or twos time you may have a hard time selling it, also diesel fuel prices and VED will go up as governments try to drive them off the road.

[ophic]

Originally Posted by DomP

Just watching this on BBC4 about the dominance of the diesel engine and it's made me wonder why diesel bikes haven't taken off. Is it a weight issue?

Weight of engine required.

Diesel's primary advantage is that it contains more energy per unit volume. You can go further on a litre of diesel than a litre of petrol.

However bikes rely on being lightweight, so the added weight of a diesel engine reduces this efficiency advantage to pretty much nothing, and would also negatively affect handling and performance.

Then there's cost. A diesel bike would cost a lot more to produce. More metal and more complexity. Then there's marketing. Would you buy a big heavy slow poor handling bike for a lot of money or a GSXR for a lot less?

I think the only diesel bikes that have any practical use are the ones for the American army, and that's because every other vehicle they use runs on diesel, so they had to have special supplies of petrol just for the bikes.

[Trev B]

Ernie Dorset used to put Robin Diesel engines into Matchless and I think AJS bikes not so long ago !!

[Bibio]

http://www.pricepartmotorcycles.co.uk/

you can get a speed daemon staggering 13hp 456cc. wonder how far you would get on a tank full

i have know about the Indians doing it for years on their enfields.

[andrewsmith]

Originally Posted by Bibio

http://www.pricepartmotorcycles.co.uk/

you can get a speed daemon staggering 13hp 456cc. wonder how far you would get on a tank full

i have know about the Indians doing it for years on their enfields.

Knowing you, lands end to John o groates

Sent from my MotoG3 using Tapatalk

[Dave-the-rave]

http://www.dieselbike.net/BritishRal...ishrally14.htm

[BanannaMan]

Originally Posted by ophic

Then there's marketing. Would you buy a big heavy slow poor handling bike for a lot of money or a GSXR for a lot less?

Ever heard of Harley Davidson motorcycles?

Put some chrome on it and a Harley emblem and there will be Americans on a waiting list to buy one.