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Re: 1949 M21 Carb Tuning
Howley #826729 10/15/20 9:51 pm
Joined: May 2004
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Australia has only 2 oil refineries that between them make less than 40% of the petrol consumed locally.
This is because our crude is better suited for lubricating oils than fuel .
Most of the petrol consummed here is imported and is nothing like the petrol you get in Europe.
There is no standard for what has to be in Australian petrol, just pollution laws about what can not be in there and the maximum amout of various fractions.
Thus what comes out of pumps down here is a mix of every flamiable solvent or scrap liquid that can be bought bulk & cheap blended with what ever is available .
Thus one day it smells like a boot shop ( excessive solvent benzine ) and the next day it stinks like paint stripper ( excessive tolluene )
When I was running the 932 on the M20 it became very sensitive to WHERE I got fuel from .
Back then Burma oil had retail outlets and they imported refined petrol , sorry fuel ( not the same stuff ) directly from their refinery .
I tried to use it all the time because it did not change day to day week to week & month to month like the local stuff did.

Now yes the bike was over carbed but it really forced home fuel quality on yours truly to the point that it would idle nicely , if a little fast on a tank of Burma but if there was any more then 50% of any other fuel in there it either raced or would not idle at all .
I do not know where West Australia gets it's fuel from .
Both of the local refineries are on the east coast so I doubt that that WA would be getting fuel from Melbourne or Brisbane as local costal shipping is near twice the price of international shipping .

Then there is weather
Perth has an average winter temp of 20 C , go a bit inland and it gets closer to 30 C and the tar roads are oft better than 40 C .
In summer you can add anothe 10 C to those + some more .
Nothing odd about a day where even the M20 can not be parked on a bitumen surface because it has become so hot the stand sinks in to the point that the rear wheel touches the road & the bike falls over .

These sorts of days boil fuel in the carb very easily .
Even in winter when running hard I have needed to let the bike sit for over an hour to cool off because it would not start due to overheating.
And this is even after a 3/4" insulating block between the engine & the carb .

BSA recommended carb tuning was correct for the time it was printed in the place it was printed and an engine that was fresh off the production line.
None of these apply to Howleys bike.
After that is is no more than a starting point where the bike should at least start so that it can be tuned properly.

Howley's bike starts & runs so there is no reason for him to go back to the starting line .
His description matched an overheated carb .
Now from further posts it might be also a miss matched set of carb parts .

On the web every one's opinion is equal
We are just electrons floating about in cyber space .
I am happy that you have found thigs that work well for you in The Netherlands
And there is a chane that they might work for Howley but every person I know in Australia is running a plug at least one grade hotter for Champions and 2 grade hotter for NGK's where the heat ranges are smaller .


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Re: 1949 M21 Carb Tuning
Howley #826944 10/17/20 8:52 pm
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@ BSA_WM20

Thbh, i am rather speechless...

Impressed what you know..... even about the weather in The Netherlands.... (we don’t have summers with 38 deg celcius right? And if so, we do not drive old bikes in that weather right?)

What is in the BSA service sheets is written regarding WM20 and M21 is based on POOL petrol....( commercial 68 octane, No. 1 grade 75 octane) lead introduced in Europe only after 1968 as far as i know... Not much better than the shitty petrol we have today in both europe and Australia i suppose, but... then Again, Australia may be very different


I am sure your help is meant and done with the same intentions as mine..


Harold / Motolab.nl
BSA: WM20 '40 M21,B31 '55 B33 '54, ZB34GS '49, DBD34GS '58
Triumph 5T '49 + T100 + speedkit
Sunbeam S7 '48
Moto Guzzi LeMans '79
BMW R51/3 '51, R100GS '89
Re: 1949 M21 Carb Tuning
Howley #826979 10/18/20 10:24 am
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I am sure your intentions were just as well meant as mine .
People in Europe tend to have very little understanding about riding condiions down here .
It just need to be remembered that what works in one location might not work in another and no tuning secifications are a hard law written in stone.
What works for me in Sydney does not work for others in Melbourne which is only 1000 km away.
When rifding down there I have to be very careful not to allow the bike on over run for extended times or the plug which never fouls here will foul down there.
I found that out the hard way twice ( cause I am a slow learner ) .

As for riding distances , most of the locals and the USA riders who were with us considerd the rides at the Halls Gap BSA International to be a bit on the short side. All of the write ups in the various BSA newsletters from overseals complained that they were too long.
It is just what prople are used to doing .

If Covid restrictions werenot in place the M20 would be hauling my fat backside up to Brisse for the opening of the Motorcycle , Art & Design exhibition in November , a 2400 km rounf trip + 300 km diversion to check the rides for the 2022 BSA National on the way back


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Trevor
Re: 1949 M21 Carb Tuning
Howley #826989 10/18/20 12:17 pm
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Are you really writing that?? Without knowing me? “People in Europe”. Really?

Sorry i am out..


Harold / Motolab.nl
BSA: WM20 '40 M21,B31 '55 B33 '54, ZB34GS '49, DBD34GS '58
Triumph 5T '49 + T100 + speedkit
Sunbeam S7 '48
Moto Guzzi LeMans '79
BMW R51/3 '51, R100GS '89
Re: 1949 M21 Carb Tuning
Howley #826991 10/18/20 12:47 pm
Joined: May 2013
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Having attended the Aussie rally the other year (and being from the UK) I like to think I have a good idea of the riding in Halls Gap and having toured Western Europe I have a reasonable idea there as well as riding around Petaluma. (There’s a lot of Europeans who have ridden further and have a broader knowledge) I tends to be that those within Europe travel more internationally than many of the countries which have a much larger land mass.

Although I was lucky, I borrowed Shane’s bike in Aus which was set up perfectly for the fuel that the bike was being used with. Also in Petaluma I was fortunate to borrow Rusty’s bike which was also set up to work with local environment and fuel.

It’s also a valid point that in Europe we tend to have the best pump fuel on the market. Although this does vary. The Dutch fuel is on par with the UK and the available fuel in Germany tends to be better still with RON Octanes around 101 for super grades.

Ps. I liked the runs in Halls Gap, it was good to be on the road and enjoying the breeze

Last edited by Allan G; 10/18/20 12:49 pm.

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Re: 1949 M21 Carb Tuning
Howley #827006 10/18/20 3:55 pm
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Yuppp, “we drive” from Norway, till Rome Italy, where +40 degrees celcius is quite normal. Crossing the Alps also that is... all on the same (standard grade plug..)
As i live on the german border, i buy often fuel for my M21 of 91 octane, still available in Germany, at least last year.. very cheap, rather low quality fuel. and far better than the Pool petrol in the UK back in The day...
That 91 octane contains even E10 (partial alcohol that is) .... good fuel for a M20 / M21 and even the B31 and B33... with their low compression..
Ohw sorry, i was out..

Last edited by Motolab; 10/18/20 3:56 pm.

Harold / Motolab.nl
BSA: WM20 '40 M21,B31 '55 B33 '54, ZB34GS '49, DBD34GS '58
Triumph 5T '49 + T100 + speedkit
Sunbeam S7 '48
Moto Guzzi LeMans '79
BMW R51/3 '51, R100GS '89
Re: 1949 M21 Carb Tuning
Howley #827014 10/18/20 5:49 pm
Joined: Nov 2012
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I thought the whole idea of military service vehicles of the WW2 era was that they could get by on pretty much any fuel they could get hold of in the field (as well as being repaired crudely by non-experts).

I would imagine North African desert service was as tough as modern Australia.

Ted Simon (of Jupiter’s Travels) on his T100 crossed the equator several times (including the above very hot/dry region) as well as across Australia, without mentioning any difficulties with fuel or plugs, though of course experiencing many other issues which he does detail.

It is too easy to assume that owners of classic bikes in small European countries only ride locally, while those in large countries ride enormous distances routinely.
There is no such obvious relationship.

Bikers are individuals who derive pleasure in different ways from their enjoyment of riding motorcycles. For myself, I’m happy with local forays for the most part (50 or so miles on a small island is enough not to feel like a stylus on a record), occasional jaunts to a festival (so up to maybe 500 miles on the mainland), or once in a blue moon a 2000 mile whistlestop trip of Europe or a 4000 mile odyssey to Morocco.
On that last journey I encountered many other Europeans, Aussies, NZ doing similar things on bikes, sadly only one was a classic Brit bike (an Aussie couple on a Commando). When we crossed paths at a campsite near Tetouan he jokingly asked if I was Ted Simon (I was with my same old Triton).

Is petrol in Australia truly as poorly controlled as Trevor suggests? Do others experience the need for plug/jetting changes when going from region to region?
Could it be just an M20 with borderline A/F ratio (rather than mid-way ratio) that makes it sensitive to minor changes in fuel composition and environment?

Just thoughts.

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Re: 1949 M21 Carb Tuning
Howley #827053 10/18/20 10:43 pm
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Standard fuel here is 91 RON Premium is 95 Super is 98 some E10 is 94 although normally sold as 91.
You can buy E85 which is over 100 but it's rare really.

The super fuels vary quite a lot over the course of a year and are best bought from a station with a high
turnover.

I have not really had any problems with our fuel on any of my bikes, i normally use BP98 which was always
a good benchmark test fuel anyway. A long time ago mixing leaded super with BP98 would give a better
result but all leaded has gone now. Just now set the bikes up to run on what's available so a little richer and
a degree or two back on timing. Above 6000 you don't notice anyway..........................

1 member likes this: koan58
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Moderated by  Allan G, Jon W. Whitley 

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