J.A.P 80 2-stroke engine setting-up & timing advice.

Hi all,
I have a J.A.P Model 80 2-stroke engine on my Landmaster80 cultivator
(1950's). Are there any J.A.P engine experts out there who can advise on
setting the thing up.
The engine refused to start last year so my father & I have removed the
engine to give it a check over. After much effort the Magneto flywheel
was removed and we can get at the points and condenser.
With no manuals or instructions how can we get it back together and
timed-up correctly?... Any advice would be greatfully received as no one
local seems to know anything about JAP engines.
The points gap is ok as it is stamped on the flywheel (0.018").
Removing the flywheel showed the magneto to be a Wipac series 161
magneto, There is no keyway on the flywheel and the cam is on the inside
of the flywheel so it can be positioned anywhere, which probably
explains why it was on so tightly and was an absolute pig to get
off.!.... (As I am only used to Brigg & Stratton 4-stroke engines this
has thrown us a bit).
There is a mark on the top of the engine casing, presumably to line
things up to.
There appears to be two small casting marks on the flywheeel (Are they
of significance)? And also what looks like a hand scribed mark on the
I have a manual for the JAP 80 2-Stroke but it only has references to a
Wico magnetos. It does mention timing to 25 before TDC... This seems
large to me but other references seems to suggest that this is correct!
I have also put some photos onto a web-page to illustrate the problem.
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Any advice would be welcome.
Reply to
Paul Waites
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Wico originally set up in West London, but later formed Wico-Pacey Corp'n which is where the 'Wipac' name turned up.
I have the factory data and service sheets for the Wico and Wipac flywheel magnetos, they are all pretty similar but I will check the timing tonight for the Jap engine, both in the Jap manual and the Wipac one.
Peter -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk
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Prepair Ltd
Can't find the 80 Book, but the Model O is timed at 3/32" BTDC, points just opening.
The 2S and 2A are both 30 degrees BTDC
Peter -- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:
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Peter A Forbes
Reply to
Paul Waites
you need to replace the key way it's called a wood key you need a new one and that will actually set the timing up when you slide the mag back on hope this helps?
Reply to
Hi Paul. I came across a J.A.P Model 80 Type 89 two stroke-engine working and maintenance instructions booklet amongst my fathers collections of books. Would you be interested in purchasing it?
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