JAP Engine

I have just purchased what I believe to be a JAP 4/3. Unfortunately someone has attacked it with a tar brush and Hammerite. Can anyone tell me where to scrape to find the serial no.?

If you look on the side of the crankcase where it meets the cylinder barrel you should see a series of numbers and letters then go to the dating thread and it will explain how to date your engine.
Cheers Bill

Heres a link to the place for Jap dating,

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Hope thats of use

Paul

Well thanks so far chaps. The no. is 4/3/N/1063/7 which makes it a 4/3 from 1941. The /7 indicates a deviation from std spec. The engine has what might be a reduction gearbox fitted onto the end of the crankshaft, three revolutions of the starting handle = one revolution of the pulley. I bought the engine from a man in Brixham who said his son came home with it 10 years ago having pushed it home all the way from the harbour (about a mile up a very steep hill). I assume the engine was plastered in its' awful Hammerite coat as it was being used either on board a fishing boat or at the harbour to prevent corrosion. If I can work out how to I will post some photos on the projects page.

Hi Alan, ( I take it thats your name)

Follow the steps in the link below on how to up load photos:-

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All the best

Paul

I know you say it's been painted with a yard brush with god knows what but on the positive side it looks as if this saved it from rusting away, so not all bad.

Stu.

alanjohnlew wrote:Well thanks so far chaps. The no. is 4/3/N/1063/7 which makes it a 4/3 from 1941. The /7 indicates a deviation from std spec. The engine has what might be a reduction gearbox fitted onto the end of the crankshaft, three revolutions of the starting handle = one revolution of the pulley. I bought the engine from a man in Brixham who said his son came home with it 10 years ago having pushed it home all the way from the harbour (about a mile up a very steep hill). I assume the engine was plastered in its' awful Hammerite coat as it was being used either on board a fishing boat or at the harbour to prevent corrosion. If I can work out how to I will post some photos on the projects page.

hi Alan...we look forward to seeing them..
regards..mike..

The JAP engine dating guide is a little confusing (mind you, the television guide pages are confusing to me) My JAP has the serial number 2A.I.83794.S. Now, I understand that it is a 2A model, if I assume that the next letter is an i rather than a one, ignoring the presumed misprint in the chart, would I be right in thinking that my engine is a 1947 and is a short stroke sports or special?

DanBoy wrote:The JAP engine dating guide is a little confusing (mind you, the television guide pages are confusing to me) My JAP has the serial number 2A.I.83794.S. Now, I understand that it is a 2A model, if I assume that the next letter is an i rather than a one, ignoring the presumed misprint in the chart, would I be right in thinking that my engine is a 1947 and is a short stroke sports or special?

it is normally classed as a short stroke 150cc or175cc of memory when i was dating mine last year
is yours with the 2 or 4 pole/ contact ignition sytstem the 4 pole ones feel like they are seizing up jump and judder as u pull them over
kev

kevjhnsn wrote:

it is normally classed as a short stroke 150cc or175cc of memory when i was dating mine last year
is yours with the 2 or 4 pole/ contact ignition sytstem the 4 pole ones feel like they are seizing up jump and judder as u pull them over
kev

Mines the 98cc engine. I'll let you know about the ignition once I get the flywheel off to replace the broken HT Lead

hi there
watch out with the soldering to the coil try to leave 1/2" of the wire still atached if you can and solder to that its out of sight and insulation tape work a treat if needed as some times the heat will break the coil down and not work after words
if your looky it might be the later bolt on cable
kev

DanBoy wrote:

kevjhnsn wrote:

it is normally classed as a short stroke 150cc or175cc of memory when i was dating mine last year
is yours with the 2 or 4 pole/ contact ignition sytstem the 4 pole ones feel like they are seizing up jump and judder as u pull them over
kev

Mines the 98cc engine. I'll let you know about the ignition once I get the flywheel off to replace the broken HT Lead

sorry dan
mind fail lol
im working on villiers 150 175 and 256cc at the minute
kev

this is a standard 2a 1947 of memory as it is stamped on the inside of the little carb side cowling on bolth my 2s

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and my propane jap 2a/s 1952
with the 4 pole electrics you can here them over the engine whearring a way
[You must be registered and logged in to see this link.] src="http://youtube.com/v/Ck7HJ_lCbPg" width="425" height="350" type="application/x-shockwave-flash" wmode="transparent" quality="high" scale="exactfit">

thanks kev

Is that the original tank on the 1947 2A as mine has a round one rather than an oval ?

kevjhnsn wrote:
it is normally classed as a short stroke 150cc or175cc of memory when i was dating mine last year
is yours with the 2 or 4 pole/ contact ignition sytstem the 4 pole ones feel like they are seizing up jump and judder as u pull them over
kev

I dont think the CC/engine type codes match up to the later industrial engines, more applicable to the Motorcycles.

Cheers Steve