Hey guys - resolution to your issues is simple trigonometry of arcs... You don't even need to do the maths... (you just gotta know and when to divide or multiply by 2) https://handymath.com/cgi-bin/arc18.cgi Enter into "Radius of Arc" (set units @ mm) 85 (i.e. Stroke spec. of NH 350) &...

Hi Graham 1/ There is a breather in the crankcase - it expires through the timing chest... just as any fluid will "find it's own level" and equalize, similarly gases behave in exactly the same way with respect to pressure & volume - if you put your tyre to say 30psi - that is per squar...

Perhaps you should cease talking to it as a cantankerous old hag or a spoilt teenage super bitch - treat it merely like the inanimate lump of metal & sundries that it is & book yourself in for a couch session with your local trick cyclist...

Correct statement from Pete, thank you! - but note such is ONLY true for the iron 4g - the ally Mk1 requirement is the large bore is the rocker feed.
(info c/o Bruce Longman).

Hi John; - I have no experience of the iron head but much with my ally Mk1's. I cannot really advise; - it's up to you to as to whether to risk damage by fully stripping to inspect & service or to leave & risk motor damage due to historic carboned oil crud & rust. Personally since the mo...

Hi Folks, Oil pipe sizes; - rockers & pressure guage on a Mk1 I am well aware there is contention here - so I checked it out with Bruce Longman (probably the most knowledgeable gent wrt Squares) It is DEFINATELY the Large bore to Rockers & the Small bore to the Pressure guage! (Apparently th...

Hi Bernie, please beware - ancient carb materials were not designed to be ethanol proof - (ethanol can leech Mazac & other alloys). Deposition within jets etc will surely occur after a months or so of dormancy. Some years back the Government deigned to warn us when UK petrol was destined to be l...

Hi Gui, the Amal spring streach may not necessarily procure a permanent resolution.
Plz refer to viewtopic.php?f=4&t=10688
where I state my intention to develop a more suitable spring...
Cheers, J.

Hi Xavier; - I do not know the clearance &/or tolerance but surely Bruce Longman will know these.
(please pm for his contact detail).

Hi Folks - with respect to streaching springs - such is unlikely to be a really permanent cure... the streach process will require repeating occassionally... I'm going to experiment by winding some heavier guage coils as permanent resolution 'cos AMAL don't make a heavy duty spring option. Such may ...