Model 20 Miles per gallaon ? + speed

beerboy · Post by **beerboy** » Sun Aug 26, 2007 7:05 pm

hello

i have just had my model 20 restored and used her today for a first longish run to travel from Oxford to a local show at Uffington, a round trip of 45 miles.

Travelling at her top speed of 50 - 53 mph i have used nearly 2 gallons of petrol ie approx 23/24 mph.

i was just wondering if these figures are typical for this size of bike.

many thanks

martin russell

itma · Post by **itma** » Sun Aug 26, 2007 7:25 pm

you have something very wrong with your carburation it would seem.
you have had it "restored" by whom?

Biscuit · Post by **Biscuit** » Sun Aug 26, 2007 9:56 pm

Things to check.

Carburettor settings, ie. needle position, needle jet size.
Is the air slide fully retracted? (Lever pulled towards you.)
Ignition timing, is it correct? - are you pushing the lever forward for advance?

Apart from pushing a presumably overhauled engine to hard, is 50-53MPH
really all that it will do?.

Edited by - Biscuit on 26 Aug 2007 8:58:41 PM

Charles · Post by **Charles** » Mon Aug 27, 2007 8:40 am

At a steady 55-60mph, with luggage but no pillion, my 60 model 20 gives 70-75mpg. Top speed, well it is a particularly smooth engine (not of my doing) and tucked in with no luggage indicates well over 90mph with standard tyres and speedo.

GSAX1 · Post by **GSAX1** » Mon Aug 27, 2007 9:06 am

Seems something is wrong with your machine. Check choke lever first as Biscuit suggested, then air filter. What kind of carburettor do you have, and how is it set up?

My '55 model 20 gives 75 mpg at my usual cruising speed of 50-55 mph, with or without luggage.

Michael

bag-o-nails · Post by **bag-o-nails** » Mon Aug 27, 2007 9:14 am

Hello Martin
My bike is an ajs 250 csr top speed 70 + down hill with the wind behind me!
fuel consumption around 60 mpg (normal running)
sounds like your running with the air lever
partly closed
if you ring surrey cycles on 01483 272328
he can tell you which carburettor you should have fitted to your bike and the correct jet size's ask him to send you his book amal carburettors (hints tips spares) it explains how
Ama, monoblock and concentric carbs work, how to set them up.with exellent tuneing instructions it also explains how to set the levers cold start etc .
cheers b-o-n

Circlip · Post by **Circlip** » Mon Aug 27, 2007 10:13 am

I have an AJS 250 and what with leakage seepage and evaporation it uses more standing still than it does riding it.

Ive got a little Bing carb on it. It doesnt like to rev much but good torque and economy.

bag-o-nails · Post by **bag-o-nails** » Mon Aug 27, 2007 11:00 am

hello circlip
what is a ~bing?it should go ROAAAAAAAAR
cheers b-o-n

Circlip · Post by **Circlip** » Mon Aug 27, 2007 2:00 pm

Well it does'nt do any of those --it sort of goes FFAAAARRRRTTTT, On a good day.

But if its not a good day it sort of goes.-- Chp Chp Chp Futt Futt Chp

I dont know what the experts would make of this?

itma · Post by **itma** » Mon Aug 27, 2007 2:19 pm

either of those are ok, on a really bad day tho it goes fucfucfucshiiiiiiiiiiiiiii