Have finally finished----

The JAP model 55, theres a few pics at the link below. Will be giving it`s
first public viewing at Scone Palace show, hopefully.
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MartinH
Reply to
martin hirst
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Looks superb :-) There was one in the Honiton Hill auction but it didn't look like that ! regards Roland
Reply to
Roland and Celia Craven
That should be quite a rarity on the rally circuit. Does it sound good with the rather 'minimalist' exhaust system?
Reply to
Nick H
It sounds good, but every now and then it gives a pop. I ran it for 4 hours yesterday and it I think it still needs a bit more setting up. It appears to run on one cylinder and the pop is when the other cylinder kicks in. I have rechecked all the valves, manifold and compression, but still does it. I know of someone with another of these and he said he has the same problem when running at low speed. It seems to be ok at around 1800 rpm.
MartinH
Reply to
martin hirst
We had a very nice Ex-MOD one of these engines, liked the second flywheel and the generally better assembly quality of the engine compared to some earlier stuff they made.
This one was nearly new and came out of storage when we got it together with a couple of Lister CE's some years ago (must have been 6 years at least as we had the Midi then)
Peter -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk
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Reply to
Prepair Ltd
Looks excellent!
Presumably it's not allowed to skateboard now it's in it's Sunday best :)
Mark
Reply to
Mark Howard
Nice to see before and after photos. I've got a JAP 5 amongst my "to be done" pile, but the 55 is something really unusual.
As to the misfire, it should be easy to figure out which one it is by taking off the plug leads one at a time. First off, swap the plugs over and see if it follows a plug. Replace plug. No good? follow the ignition path back to the magneto swapping bits from one line to the other. Still no good? Narrow the plug gap on the failing cylinder.
So, it's not the ignition then ;o))
Make up a thick rubber manifold gasket to go between the carb and the manifold. By doing up the flange nuts a bit at a time, you'll notice it runs better or worse. when it runs evenly, make up an aluminium (or red fibre etc) angled flange piece to permanently point the carb towards one cylinder or the other. This happened to 1600 Datsun Laurels in the seventies and the factory mod was one of these tapered manifold spacers - and it was a 100% cure!
I'm now reminded that the CV flat four still calls to me ..........
Regards,
Kim Siddorn,
Reply to
J K Siddorn
Thanks Kim, have tried the plugs etc. It is no2 cylinder thats the problem. Will try the gasket as you suggest.
MartinH
Reply to
martin hirst
Perhaps a slightly hotter plug in that cylinder? I have had a similar problem with both air and rad cooled in-line twins. At lower speeds one cylinder is being overcooled and the plug oils up. just a thought Roland
Reply to
Roland and Celia Craven

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