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by john.bebb
Sun Jul 05, 2020 5:53 am
Forum: Four stroke
Topic: Angle BTDC - ignition setting
Replies: 9
Views: 329

Re: Angle BTDC - ignition setting

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) &...
by john.bebb
Wed Jun 24, 2020 2:05 pm
Forum: Four stroke
Topic: Squre Four Engine Breather
Replies: 10
Views: 272

Re: Squre Four Engine Breather

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...
by john.bebb
Wed Jun 24, 2020 1:33 pm
Forum: Four stroke
Topic: My Sq 4 hates me!
Replies: 6
Views: 379

Re: My Sq 4 hates me!

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...
by john.bebb
Wed Jun 24, 2020 1:25 pm
Forum: Four stroke
Topic: Which oil pipes square four
Replies: 3
Views: 173

Re: Which oil pipes square four

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).
by john.bebb
Wed Jun 24, 2020 1:16 pm
Forum: Four stroke
Topic: Iron 4G Head Question.
Replies: 6
Views: 230

Re: Iron 4G Head Question.

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...
by john.bebb
Thu Jun 18, 2020 9:23 am
Forum: Four stroke
Topic: mk1 square four . oil issues
Replies: 39
Views: 1668

Re: mk1 square four . oil issues

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...
by john.bebb
Wed Jun 10, 2020 3:22 pm
Forum: Four stroke
Topic: SQ4 Mk2 starting issues
Replies: 38
Views: 1812

Re: SQ4 Mk2 starting issues

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...
by john.bebb
Wed Jun 10, 2020 3:15 pm
Forum: Four stroke
Topic: Square 4 MKI - more troubles
Replies: 28
Views: 1128

Re: Square 4 MKI - more troubles

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.
by john.bebb
Wed Jun 10, 2020 2:51 pm
Forum: Four stroke
Topic: Crankpin to big end clearance
Replies: 10
Views: 391

Re: Crankpin to big end clearance

Hi Xavier; - I do not know the clearance &/or tolerance but surely Bruce Longman will know these.
(please pm for his contact detail).
by john.bebb
Wed Jun 10, 2020 7:19 am
Forum: Four stroke
Topic: Mk1 Sq 4 Carb
Replies: 21
Views: 735

Re: Mk1 Sq 4 Carb

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 ...

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