How "economical" is a Scott?

[Erik]

Hey all,

Since I own my Scott I find this bike far from ecomical. Not that that was the main reason for buying it….

I cannot get more than about 9-10 km out of one litre of petrol. If my conversion is correct that’s about 27 Miles to a gallon. Does this sound normal?

Erik

[efr215]

I make it 28mpg and even if you go flat out all the time that is terrible for a road bike! I’d have expected 55/60mpg at least.
For comparison my little Moto Rumi 2stroke twin does about that, it’s only 125cc but then there is this big fat bloke sitting on top of it! I used to do a daily commute to central London in rush hour traffic (80miles/day) on an 850cc Norton Commando and that used to turn about 63/65mpg. I’d expect 73/75mpg any day from my old Vincent Comet and I’ve even managed 85mpg on a run by being very careful with the right wrist.
That pedal down by your left foot rest is usually the brake on British bikes, you could try taking your foot off it? Te! He!

[chstorm]

Hey Eric!

All two-strokes are great “gas-guzzlers”. Mine is a bit more economical, but not much. A 600cc two-stroke will have a consumption almost equal to a 1200cc 4-stroke.

If I remember correctly, you have a 210 main jet. Try to reduce that. I use a 200 now, and it seems to work OK. A 190 may also be more correct. Standard on Scotts seems to have been 170, but with a gas-flowed engine a 170 is too lean, as I discovered when one of the gaskets under a transfer bridge blew.

Try the old trick: Warm up the engine properly – run full throttle for as long as you dare – at least a few hundred meters – cut the ignition – declutch – stop the bike. Unscrew the spark plugs. Their condition will tell you if the main jet is correct. They should be quite clean and light brown.

Kind regards,

Carl

[Jan Buchwald]

To the best of my memory, mine runs something like 14 km/l

[Ian Parsons]

I reckon that my 596cc TT Replica does about 45 – 55 miles per gallon depending how it is ridden. The carburettor settings and jet are what The Book of the Scott recommends and the plugs seem fine. I also got the same from a 498cc Flyer with a DPZ engine fitted.

My 2 Speeder does about 65 mpg but this is a much softer engine. What do other owners get from their Scotts?

[Richard Moss]

Ian said it .. a lot of this will be ‘depending how it is ridden’
The Crossflow is a bit of a blunt instrument for scavenginve at higher revs i think, and of course if you have a tendency to ‘wring its neck’ then youll be getting through the juice. mostly unburnt and down the exhaust!

The recent advances in two stroke technology have been in the use of Direct fuel injection so that the fuel is only administered to the cylinder once the exhaust port is closed. The Air is admitted as usual with a sensor on the butterfly valve to give relevant information to an Engine Control Unit which controls the fuel flow.
This stops the amount of fresh unburnt gas escaping down the exhaust, i assume mainly during the rev band in which the exhaust is not charging the cylinder.

Economy is an indication of efficiency.. and of course can be improved by deliberate testing through incremental changes. I would imagine that atomisation is achieved more successfully with some carbs than in others, though i dont think the three jet is generally hailed as a sentinel of metering effectiveness (no offence intended ). It will be a combination of things.

I am studyng exhaust technology for two strokes at the moment and the possibilities to raise the efficiency of an engine through the exhaust is huge.. but the problem with the Scott is that it is so low revving that to get an expansion exhaust effective within the range .. you are looking at a system a metre and a half long even before the silencer!

Ive just got to get those revs up otherwise ill have to make a roll cage out of the exhaust!

Its all so interesting. : )

[David J Waring]

I agree with Ian on 3 speeder expectations for both vintage, and also my 1947 Flyer.

My vintage 2 speeder experience is limited to a 10 year ownership of TK 5209, a 1930 2 speed super 498cc, which it’s previous owner ran with a 2 jet Binks carb., on an inch & a quarter OD inlet stub. I found cold starts & running were good, but hot re-starts were dreadful.
Short supply of Binks jets caused me to swop to an Amal, which just happened to be available at the time, with a range of jets off the shelf. It was an Amal 276 on an inch & an eighth stub, where I experimented with No 3 and No 4 cutaways, and jet sizes 110, 130, 160, 170 & 180. I settled for No 3 and 160, where I’d expect the upper end of the 45 to 55 mpg; don’t think I ever made Ian’s 60 mpg.
However, the late Chris Boorman ran KU 8343 (1926 2 speed super 498cc) on No 4 and 180, for many years. It’s present owner has since made changes – Scotts obviously play up when they are sold !

An exception is my 1914 veteran 486cc on a 3 jet Binks, set up to a level of reliable satisfaction by it’s previous owner, which still performs very well for starting and running, but only delivers 35 to 40 mpg.

[Springming]

I have found with most of my Scotts that the fuel consumption is rather like an aircraft engine and best calculated in time of hours running, rather than MPG.
Perhaps that is why the “flying flea” Scott aircraft engines were developed !

Regards to all…Peter.

[Erik]

Thank’s guys for all the replies, it makes nice reading…;o)

I know old two strokes are not known for their moderate use of fuel. All my Vespa scooters (from 125-200 cc and 1954-1967 do about 20 km a litre (roughly 55M/g) and given the cc this I did think this was not very economical too… Especially as I once had a Yamaha 250 fourstroke V twin that happily did 95-100 M/g doing two up, in the hills with trailer!

But, Holland has so much petrol stations that even with 5 M/g I would never get stranded without fuel..

Kind regards,
Erik

[efr215]

There is one other possibility that might be worth considering and help get things as good as they are going to get. Many moons ago I treated myself to a Colortune kit, (their spelling). I have just checked and they seem to still be in business but now sell at an eye-watering £35.00 and up to and over £65.00!!!

I think I paid £7/10s/0d for mine and while I can confirm that they do work well and would be useful for ensuring that each cylinder is getting its share you’ve got to ask yourself if they are worth 70 litres of petrol!

[Jan Buchwald]

Quote efr
“That pedal down by your left foot rest is usually the brake on British bikes, you could try taking your foot off it? Te! He”

Knowing several british bikes ability to brake, it won’t make much difference.

[efr215]

Isn’t it nice to know that you are not the only one with an evil sense of humour?

Even if it is another perishing Viking!

[Author]

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