Mileage

Captain scarlet said: ".... have you seen those little primates go! ;-D"

There should be a law against hanging around zoo's in a mac. ; D

Jag said: "The top gear or 6th gear would become an overdrive gear."

In terms of removing a source of relatively high losses, devising a transmission which, when in top gear, by passes the gear cluster entirely. How you would achieve that, I have absolutely no idea! You'd need an expert for that.

I can hear the swish as the technical stuff flies over my head (very interesting though!) so I will restrict my comments to experience. I've tried to compare basic like for like bikes here.

A 250cc bike does loads of mpg, I seem to remember a Honda 250 single (CB250R?) which did 80 odd mpg back in the eighties. Now a 250 is fine for urban use but not really enough for motorway cruising.

A 500cc bike has plenty of power for practical use but 55mpg seems about right for careful use, CB500/CX500.

A 400cc gives enough poke to cruise at 80mpg yet remains the same size and weight of a 250 (I'm thinking CB250N/CB400N etc...), and gives pretty much the same fuel consumption too. The size is light but fine for most usage, even with a pillion.

A 400cc single is a bit lumpy for easy use IMO, a 400cc 4 is smooth but doesn't seem to give as good mpg (Honda 400/4 vs CB400N), so a twin seems the best compromise, being simple and smooth enough for commuting.

Surely all this engine managment etc... development can make even a normal engine much more efficient than in the 80's. I'm sure advances in rolling chassis have also been significant and so weight savings should also be quite possible. As for style, the old fashioned retro style has an awful lot of practicality, which is why they looked like that in the first place.

As for 'flat out' efficiency. My little Mobylette will give circa 100mpg flat out at 30mph, which is way more than the V Strom would do trickling along at the same speed. Is this relevant? Maybe only in that a bike that only does 30mph flat out can be built a LOT smaller than a bike capable of 130mph, or is the engine more efficient when it's flat out all the time. Mind you I suppose the frantic pedaling on the hills does help mpg - now there's a thought....
Maybe we've found another use for the monkey?

As for the Guzzi, I found tacking on a half tonne Russian built sidecar to the side does effect mpg, but only by less than 20%, which considering the weight, frontal area and extra wheel doesn't seem too bad.
I suppose the reason there aren't many outfits around is they have a natural affinity with hedgerows & tend to combine all the disadvantages of a car with all the disadvantages of a bike (apart from the exceptions given above that is. Incidently they are also very good for bike rallys - like the 'Farmyard' next week - as one can ride them across wet muddy fields without falling off and looking a prat in front of 6000 other bikers).

Thank you Pittsy, and yes, it was the rs I was thinking of. My sister had one which she crashed regularly. The forks went one way and the frame the other but it refused to die.

As for the sidecar stories, I could stop, but then I wouldn't be able to tell of the time when I was trying to get an old Dnepr up a short, steep, snow covered road when a crazy bloke rushed out of his house and emptyed a fire extinguisher over me. It turned out a float bowl had worked loose and sprayed petrol up my right leg, which somehow ignited. I was concentrating so hard on getting up the hill I hadn't noticed. Took ages to get the powder out of the carb.

Or the time returning from The Woodman (near Hebden Bridge) on biker night on an ancient Ural. I usually went with a mate who dressed as Rommel while I dressed as a Russian soldier, we had a machine gun mounted on the chair which we had fabricated. On this occasion another mate wanted to go so I took him in the chair while Jim went on his GS550 rat. We were hammering along when some traffic lights went orange, he speeded up and went through (like you do) but Urals don't do that (speed up) so the lights had gone red by the time I noticed the cop car sat by the side of the road. I skidded to a halt then felt a tap on my leg, my passenger wanted to know what to do with the machine gun. We just sat there and looked innocent for a while until the lights changed. I can only assume the police decided that a Russian soldier on an machine gun equiped outfit in hot pursuit of Rommel through the Yorkshire night wasn't worth the paperwork.

You may laugh, but it's been tried. Google for an image of Rollie Free on his Vincent Black Lightning at Bonneville salt flats. He wore swim trunks and goggles. Just that, nothing else.

Hi Dean 15,

Flaming pink speedo's is the only way to go with matching helmet and sneakers. Got to prevent excessive movement. Keep things under control so to speak and prevent excessive wind flapping.

I know the picture you are refering to. Amazing !

Vincent Black Shadow, now there's a real bike. The heck with MPG with that one.

I know MPG is important to a lot of riders but when it comes down to it there's NOTHING like twisting that throttle in high gear and feeling the engine set down and pull away like crazy away from traffic.

I love it !

JAG

Just returned from a round trip from Yorkshire to Plymouth. Weather was constant, generaly good, light winds, some rain near Bristol. Traffic was busy but without any hold-ups. I rode pretty much the same throughout the trip, cruising at around an indicated 80mph, with the exception of about 6 miles in the Plymouth area (using Asda petrol) and the final 25 miles where I eased off the throttle as much as possible while maintaining a steady 70mph (using Shell petrol). The bike was a V Strom 1000.

I used 3 different types of petrol to gain a comparison.

Sainsburys expensive petrol returned 51mpg
Asda normal petrol returned 46mpg
Shell expensive petrol (V-power) which returned just short of 60mpg

The findings are pretty much what I would have guessed at based on previous experience.

(I have no connection with any petrol companies by the way!)

I have argued with the missus for ages about how 'expensive' posh petrol wasn't, and long suspected that cheap supermarket petrol wasn't as cheap as you'd think either.

As I was doing a long run I took the opportunity to test it. Even taking into account the variations (Plymouth, a bit of rain & the last bit) the difference surprised me, particulaly the Shell section. It was the longest continual ride I've done (Taunton to Wakfield) in over 30 years of riding due to the range and good fuel consuption.

I like Halifax :-) the Woodman has long gone though :-(

No, the V doesn't have a knock sensor, and yes the octane rating is higher for the posh fuels.

The general consensus on (USA based) V sites is that the bike should if anything run worse on high octane fuel and at best make no difference. I don't know about the theory, just the results posted. I wonder if US fuel is different to UK spec? Or maybe some posters just repeat what they've read elsewhere and the 1st bloke just made it up??? On a purely subjective level the bike felt happier on the Shell Vpower, a bit smoother, very hard to say with any reliability.

The last 25 miles I was trying to stretch the fuel out a bit to last until I got off the motorway & into town. Motorway fuel is silly expensive. My calculations indicated I would be fine but I don't like pushing! I didn't want to mess up the experiment too much so compromised on 70mph.

Thanks for the kind comment jesymall,

I just wish I knew the graph you were refering too?

JAG