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Re: Off topic Doncaster pick up

It's a damned site easier to ask for 19" tyres than the 482.6 mm type !

....but Norton spoil it by referring to the OD of 26" !

Re: Off topic Doncaster pick up

It's incredible when you start to think about it...
- bore / stroke sizes: millimeters
- engine capacity: cubic centimeters
- petrol tank capacity: gallons
- oil tank capacity: pints
- bearings: some are imperial, some are metric
- tyres: imperial
- chains: imperial
- tyre valve cap thread: Mechanical Engineering (ME)
- threads on most electrical components: British Association (BA)
- thread on spark plug: metric
- threads on (Albion) gearbox parts: Whitworth (BSW)
- threads on petrol taps etc: BSP
- threads on speedometer: metric
- threads on rest of motorcycle: Cycle (BSC)
- for most nuts and bolts you need W / BSF spanners, but on some adjusters you need AF spanners
- on electrical components you need BA spanners
Jan

email (option): wd.register@gmail.com

Re: Off topic Doncaster pick up

Yep, Jan and many of the cycle threads on Norton (and I believe RE) were 'specials'

On the other hand, this was all part of what made motorcycling accessible only to true enthusiasts :-)

Re: Off topic Doncaster pick up

Rik
... many of the cycle threads on Norton (and I believe RE) were 'specials' ...


Oh yes, I forgot to mention these...

The speed is measured in Miles per Hour, and a metric hour is identical to an Imperial hour! Yes, standardisation at last! And the charge is measured in Amps, even more standardisation!

On the other hand, engine power is measured in BHP, and although James Watt was an Englishman, not in kiloWatt.

The advantage with motorcycles is that British bikes and continental bikes have their handlebars on the same side of the vehicle!

Jan

email (option): wd.register@gmail.com

Re: Off topic Doncaster pick up

Do old European motorcycles have 1" handlebars or 25 point something millimeters ?

Re: Off topic Doncaster pick up

Doncaster M.B. has a total area of 220 square miles. Just thought I'd chuck another irrelevant fact in :-)

Re: Off topic Doncaster pick up

Rik
It's a damned site easier to ask for 19" tyres than the 482.6 mm type !


Yes, but those tyres are made in inches and labeled in inches, the piston is made in mm but that is denied and converted to inches AND rounded off.

And how about the oversize +.020 ?? would that be made in inches or also converted and rounded off from 0.5 mm? The difference is significant with 0.08 mm and in case of +.060 it would be 0.24 mm.

My guess would be that it is also converted but quite handy to know for sure when you have to bore the cylinder...

Re: Off topic Doncaster pick up

The key thing is not the piston size (diameter) but to bore the cylinder to the correct skirt clearance for a given application....

Metric versus Imperial is something I have often pondered, or rather the mixing of the two...

I could imagine spark plugs retaining a metric thread as they first came into use in Europe and were supplied by European manufacturers...

However, in the 40s and 50s, for example, when the Imperial system was supposedly the 'standard' in the UK metric and Imperial sizes were mixed as a matter of routine...

Regarding Smiths speedos I'm still unsure of the thread classification used...B.A. would (should) be the one used as an instrument thread and this is an Imperial thread form...
A check on its origins will reveal that whilst it is an Imperial thread, the form and specification is based on metric dimensions... but it is not a Metric thread..In other words it doesn't conform to standard metric thread forms..

Pitches, overall dimensions etc. are very close on these small metric and B.A. threads sizes and I suspect the use of a shadowgraph or similar would be needed to definitively determine which thread is used...

Any comments would be interesting on that question...Ian

email (option): ian@wright52.plus.com

Re: Off topic Doncaster pick up & more

Ian Wright
The key thing is not the piston size (diameter) but to bore the cylinder to the correct skirt clearance for a given application....



I know that is common practice but don't understand why the cylinder is not just bored to the given diameter so that the factory decides what the clearance will be instead of the men who bores it.

That seems much more logic to me and seems also very handy when you loose the info which normally comes with a new piston.

The cylinders I had done had the exact diameter which was on the piston when they came back.

Re: Off topic Doncaster pick up & more

And THIS Friday , my supplier of chimney materials , said , just to confirm your order thats, eight meters of six inch flue with a 25o mm long extended long tail adaptor of six inch internal dia, I replied as I always do all the flue is made on German machinery, and everything is metric,even the stainless is supplied to the manufacturers of the finished products in metric size, its not just the old boys who this mixing imp an metric thing, ALL the youngsters do this why?

email (option): warbikes@gmail.com

Re: Off topic Doncaster pick up & more

Regarding the handlebar sizes question, somewhere above (this thread is seriously hi-jacked!!)

There were inch and 7/8"sizes in Europe same as in the UK, but Zundapp before and during the war decided to use an inbetween size of 24mm. very strange indeed, so if you find any of that size, they must be Zundapp!

Cheers,

Lex

email (option): welbike@welbiXX.net (think about it!!)

Re: Off topic Doncaster pick up & more

Michiel,

Working on the M23 I see. The Hepolite piston number denotes an 82mm OHV piston for M22, M23, Q21 and Q8 (low compression).

Talking bout a serious hijack....

Kind regards,
Leon

email (option): leonhop3_at_planet_dot_nl

Re: Off topic Doncaster pick up & more

Thank you, Leon, I know what it is, but was triggered by the description of 3.2283" instead of 82 mm what they actually mean.

Next time will start a new topic, sorry for my part of the hijack, at least you get quite some attention for the pick up!

Yes, I started with the M23, luckally found the correct frame with the correct oiltank fixing so now full speed ahead.

Cheers, Michiel

Re: Off topic Doncaster pick up & more

Michiel,

I don't mind the hijack. Any attention is good. I knew you would know what piston you have. The funny thing is that I have been after that piston for a long time and now I have almost all sizes.

Good to hear that you started. It will be a beautiful bike no doubt when you are finished.

Regards,
Leon

email (option): leonhop3_at_planet_dot_nl

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