My little JAP

I've started doing some work on the JAP that I can't name yet... Is anyone interested in seeing how it goes?

I know it's 'just' another small air-cooled 4 stroke but I like the simplicity of them if nothing else so I thought some others might do too.

Anyway, if there's any interest at all I'll post pics and some words to got with them

Paul

we all have or have had air cooled engines
so yes there are a number of interested partys on this forum
from big to small ,horizontal to vertical, 2 stroke, 4 stroke ,hit and miss, petrol/ paraffin, gas diesel ect ect
they all are in our past and getting older by the year
i have 4 different japs myself
loads of villiers aircooled
and a couple of watercooled villiers two strokes ,
petter a1 aircooled"s
jlo 2 stroke marine
just sold a lister a
and bought a opencrank amanco 2 weeks back

so show us your engines and dont be shy we dont bite ,and were not biast on this site
all engines are welcome on our freindly site
enjoy and post your pants off
kev

Yes post away the this forum is for every type of engine
Nice to see members posting more you never know you might start anew craze
Jonesey

Yes don't be shy, we hope that new members can get tips etc on engines how to overhaul or repaint it's all we can do to help the hobby along to anyone new.

Stu.

kevjhnsn wrote:
enjoy and post with your pants off
kev

How do you know about that???

Aaaanyway...

So here it is not long after I picked it up



I'd given it a bit of a scraping off to get rid of some of the gunge. After that it sat around for quite a while while I looked around for motivation...

I found some in a box the other day so thought I'd use it to make a start on the JAP. I got it a bit stripped and found these governor parts in the sump...



To be fair, I knew it was broken - looks like the external arm was removed at some point and the engine run, the weights over-extended and hit the inside of the crankcase as well as a bolt, this broke some of the weight mounting lugs off the governor gear and let all the bits fall into the sump.

It's actually not as bad as I thought it was going to be, at least I found all the parts so I can see how it's supposed to work which means I can fix it.

The exhaust valve was properly stuck and needed drifting out, I was going to ream out the guide but I couldn't find my adjustable reams so I used a drill bit (yes, I know) and it's now moving nice and free with next to no play.

Currently, it's stripped and partially cleaned. I haven't taken out the camshaft or the crank bearing and seal (not sure if I'm going to yet).

Known 'faults':
Broken governor gear (to be remade)
Top compression ring was seized in and broke on removal (I'll either move the middle one up and live with the remaining two or see if I can find a suitable one in my boxes of bitses)
Head has some broken fins and partially stripped spark plug thread (I'll either clean it up and leave it or experiment with chemical metal)
Valves need some serious lapping (in progress)

Missing or wrong parts to be 'found' or made:
Air shroud / cowl missing
External parts of the governor missing
Totally wrong exhaust (I'll make a nicer one)

Neither of those lists are complete

I'm not looking to spend any more on parts than it cost me to get the engine (nothing, it was free) but I'm not counting consumables (paint, grinding paste etc.) that I already have, same with any metal stock.

Let's see how it turns out

Paul

p.s. I've got some more pics of how it is but I have to get them off the camera - I might do that tonight, or maybe tomorrow...

hi there
just to say JAP did make that style of exhurst for the smaller ones and 2 strokes
not just the pepper pots we see most of the time
is the a serial number stamped onto the block
normally around the 1-2" below the finns on a flat section ??????
i do have a smaller jap cowling air shroud
its one smaller than on the jap 2a size engine
with a mounting point on the front for a fuel tank ???????????
does this sound promising to you
if so will post a pic of it tomorrow when i dig it out again lol
kev

Paul you sound a bit like myself, when I pick up a cheap engine I don't like to go wild spending a fortune getting them running again, so I tend to have a look a auto jumbles and ebay to see what I can pick up cheap or even try to make some of the parts up. I know this can take a long time to restore an engine but these engines can be picked up cheap so if all else fails just pick up another engine for spares and build one out of the two. When I stripped my Jap 2a I found that one of the governer weights was damaged on that so I've took it from 4 weights down to 2 and hopefully it should be ok once rebuilt as it's not going to be run at high revs.
Good luck with the restorations and keep the pics coming and you never know someone might have the parts you need.

Stu.

kevjhnsn wrote:hi there
just to say JAP did make that style of exhurst for the smaller ones and 2 strokes
not just the pepper pots we see most of the time

I've seen them use this style on some engines but I think this one is originally from a villiers 25c. If I'm anywhere near with the ID then it was a plain manifold stub on these with a remote silencer...

kevjhnsn wrote:
is the a serial number stamped onto the block
normally around the 1-2" below the finns on a flat section ??????

Nothing like a serial number anywhere on it, and I've had a good look! I've found a few stampings, but these have been either patent numbers or (possibly) a date or production number. I'll put some pics up of these at some point.

kevjhnsn wrote:
i do have a smaller jap cowling air shroud
its one smaller than on the jap 2a size engine
with a mounting point on the front for a fuel tank ???????????
does this sound promising to you
if so will post a pic of it tomorrow when i dig it out again lol
kev

Possibly promising, if you could get a photo then I can see, then maybe get some measurements to see if it's close?

Progress photos to follow...

stationary stu wrote:Paul you sound a bit like myself, when I pick up a cheap engine I don't like to go wild spending a fortune getting them running again, so I tend to have a look a auto jumbles and ebay to see what I can pick up cheap or even try to make some of the parts up. I know this can take a long time to restore an engine but these engines can be picked up cheap so if all else fails just pick up another engine for spares and build one out of the two.

I never like being parted with my money! Another engine for spares might be a good idea apart for two things:
1. I've never seen another of these engines 'in the flesh' before and
2. every time I've got a second anything for 'spares' in the past I've ended up doing that one as well!

stationary stu wrote:
When I stripped my Jap 2a I found that one of the governer weights was damaged on that so I've took it from 4 weights down to 2 and hopefully it should be ok once rebuilt as it's not going to be run at high revs.
Good luck with the restorations and keep the pics coming and you never know someone might have the parts you need.

Stu.

It's likely to be fine on 2 weights rather than 4, if you're running it slow then you're unlikely to hit the governed speed anyway - if you find it does over-rev or start to surge then a change to a lighter throttle spring should sort that out right enough.

Paul

OK, on with the progress so far...

Valve seats looked positively lovely once I got the valves out - can't see a thing wrong there at all



Same with the valves - pretty much perfect.........



I thought I'd give them a little wipe off anyway



Honestly though, that was more than 2 hours of lapping/grinding to get them like that...

Here's where we are tonight, everything ready to clean up.



I think the plan now is to clean it up a bit so I can handle it easier and then put it back together without the governor for now. This way, I can check it's going to run right (can't see why it won't with a bit of stroking) and get the 'trolley' for it built. Before it's painted it'll be easier to make or find new or replacement parts too.

The intended use is strapped to an old car alternator (I've got a few in the shed) and use it as a battery charger / jump start unit.

Once I know that it's a goer and it'll drive what I want, I'll strip it back down, fix the governor, clean it properly and paint then rebuild it again. Thankfully, the head gasket is copper so re-using that a few times will be fine, it'll just need annealing between uses and the rest of the gaskets are going to be Kellogg's finest (well, cheap tesco cornflake packets) so no expense spared there either!

By cleaning properly, I mean blast it - I've got the proper kit to do it, just need to finish building the compressor (that's another thread for later - two 1940's/50's receivers with an auto-start petrol driven vintage compressor unit...) and get the shed to put the cabs in done... Why I can't just have one project I'll never know...

Paul

hi there paul
will dig it out tomorrow for definate
and post the pics
kev

Some nice attention to detail there. Should be a reliable little show engine when finished.

Great work Paul, your very much like me with a few projects going at once, I'm trying to sort out a cabinet to shot blast as well but everytime I get a cabinet I end up using it as storage LOL.
I understand what you mean that even an engine bought for spares could be a runner so to good to break, I tend to end up buying a few the same so I can make a few good ones and have one as spares.

Stu.

DanBoy wrote:Some nice attention to detail there. Should be a reliable little show engine when finished.

stationary stu wrote:Great work Paul,

Thanks for the compliments

To be honest though I can't take all the credit, I have had some help...



That's my supervisor in the red top

Paul

any use mate
kev

kevjhnsn wrote:
any use mate
kev

Possibly... I'm going to make a cup of tea and take some measurements

Paul

a little rusty but not to bad for its age
not as bad as it looks on camera
no dents to be bothered with to me
and its all there in one piece
ok mate have a brew and well measure up and see
kev

This is where it'd have to mount



I think it's offset the wrong side, on my engine the valve position is to the right of the cylinder in that photo.

I think it might be a bit small too - hard to tell with nothing else for reference but it would need to be these sizes at minimum



The 10" upright measurement is from the crank (middle of the hole) to the top of the head.

That one looks like it's off a 2 stroke - not that it matters where it's from to me...

Paul

no sorry mate
its too small for you by about 3" in all ways
will have a measure up of a couple of my other small japs and see what is the size and tell yyou what model its on of mine
as i still dont know what engine size this is of yours
kev

Thanks for looking, it's always worth a shot. Well, as for size it's 186cc (actually 190cc now 'cos it's had a +30 piston fitted ) so I'd put it somewhere between a 2A and a 4/2 if that narrows it down at all...

There's a picture close to what I think it should be like on 'another' forum, in the identification section. Or, same picture is in the A-Z. Only problem is that, like I said, I've never seen another one the same.

I really should have something I can make fit somewhere though, I'll just have to have a proper look soon. Unfortunately, I've nearly finished the box of motivation I found Must get more!

Paul

There is a Jap 3 model if memory serves me right, it's a shame we did have a good selection or Jap pics but a former member left and deleted the pics.

Stu.

my supervisor keeps running off with my tools.got to laugh he trys all them on his little bike then brings them bag.then asks for the big spanner.

stationary stu wrote:There is a Jap 3 model if memory serves me right, it's a shame we did have a good selection or Jap pics but a former member left and deleted the pics.

Stu.

The 3 has bore*stroke of 57.5*57.5 mm. Mine is 64.5*57 mm.

I'm pretty sure it's a 4/b or a 4/f, the 4/f is reported to be a lightweight (53lb!) version of the same engine. The only reason I'm leaning toward 4/f is the base of the crankcase doesn't match the illustrations I've seen of the 4/b. (note, if you search for the 4/b you'll likely get results for the 4B 500cc speedway engine, a little different!) There are a couple of very poor quality videos on the 'net of the 4/f, but it's hard to make anything out, except the base being the same shape.

Someone on here did ask for a manual on the 4/f about 18 months ago, but they haven't been around for a while...

Paul

will i have a
2a
2s
4 or a 4/1
4/2
4/3
e30 villiers but is a debadged jap 4/3 2 yrs younger than when jap were gone
5
6
none of mine seam to be the write size for yours mate
kev

Thanks for taking the time to look anyway Kev, much appreciated. I was sort-of expecting no others to fit...

I've got a 4/3 and I know it's smaller than that, and I did have a 2A and it's bigger than that.

I'm (hopefully) getting a bit of info that might just aid me one way or the other so with any luck I'll know what to do!

Paul