classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: ColinF on May 30, 2019, 08:57:10 PM
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Just got hold of a 600cc JAP sidevalve engine with the intention of making a vintage looking special around it .For the record, i'm not a hipster and it wont be a "brat-tracker " or a "beard -racer"!
I managed to find the engine number which is UCZ/W 80359/4 and i understand that u=600cc,C=sports engine,Z= dry sump and that W=year ( 1930 or 1950 ) and believe the last digit refers to any deviation from std.
I know these things were fitted to large rotavators etc ( Howard Gem etc).
So what i want to know is.......
Does the sports engine denote what it might have been used in?
Is there any way of telling if its 1930 or 1950 ? When was this engine first built?
Is the fact that the cooling fins on the head run front to back significant ? I've read of other people changing to this type of head from rotavator ones which had transverse fins.
Any help would be appreciated.
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What does it actually look like ?
https://s3-eu-west-1.amazonaws.com/lot-images.atgmedia.com/IB/264/5168/916-201379154735_original.jpg
https://farm6.staticflickr.com/5055/5409498093_9d682144c9_b.jpg
There seems to be a whole industry out there making such things these days....
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A photo would help distinguish between 1930 and 1950.
I suspect we might find that "C" in this context is not "Sports", but let's have a look first.
Leon
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https://farm6.staticflickr.com/5055/5409498093_9d682144c9_b.jpg
There seems to be a whole industry out there making such things these days....
Nice one R: it would be funny, except that in the Facebook age few can differentiate between the "NUT dirt track racer" and the real thing. Not really a problem with the NUT, but fake racers (Rudge, Norton, American board trackers, etc.) are reaching a level of sophistication able to fool even the one-make clubs.
Leon
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Hi
The 1930 engine would have a one piece casting for the cylinder and head (non detachable)
Also I do not think the dry sump system became available till mid thirties
The industrial engines usually have the engine / crankcase mounting lugs as wide or wider than the crankcase itself
John
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Well my J.A.P. engine chart does confirm UCZ as being a 600cc sidevalve sports engine and W as being of either 1930 or 1950 manufacture. As mentioned above a photo will sort that one.
I think the J.A.P. idea of a sidevalve sports engine dates from pre 1914-18 First World War days and was a little dated even by 1930 standards cos' sporting it ain't. But that depends on your idea of sporting doesn't it.
Back in my yoof I went through a lengthy sidecar phase and have fond memories of various 600cc outfits. VB Ariel, Big 4 Norton and a Big Pussy. None startling fast, max 55-60mph but would do it up hill or down hill, loaded to the gunwales or empty. I find the idea of a 600 sidevalve sporting solo dull but same engine in a sporty outfit? Brilliant!
As JFerg of this parish will confirm, outfit owners are always welcome in any riding group cos' guess who gets to carry all the peace of mind necessaries and godwot. No one wants to haul extra weight if there is an alternative.
Outfits are fun. Old thumper outfits especially so.
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I d bet a weeks pay that its a 600cc mk III,type 5......which is good in one way because it has a ball bearing d/s main.......the 600cc mkIII,type 3 has loose rollers in a cage ,a la HD/Indian.........if it has a detachable head ,it aint 1930........commonly seen here are from the railways....not railcars with big rorty 1323cc twins.......but things like Autotrucks on the stations,and lots of mobile machnery with the engines as starting motors.....the Ruston 6 VPH had a 600cc,wheras the Dorman 6DL only needed a 500.
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I also believe the C stands for a customer order,not sports................if you cant do a pic.....the Howard engine has a large flange around the D/S crankcase......the others are motorbike crankcase type........some rail ones have a crankhandle dog in the timing case.....and in the past,i have left this type for scrap......not now ,obviously.
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Thanks chaps for the quick replies. I do realise it's not a sporty engine, that was just what i got of the engine codes online.I have modern classics for sporty riding and just wanted something fun to build and to be able to collect random parts that look right at autojumbles. I will post pics when i've cleaned it a bit. Be warned, it is in pretty much "as found" condition" but it does turn over ( it was local and i didn't pay a lot for it ) .It is missing carb and mag, also the timing gear ( available 2nd hand online) and cover. It does have separate head so 1950? Any idea what the last digit ( No 4 ) means? Not really bothered about age as it will still be more 30's style.Thanks all for the input.
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Colin,have a look at the Autotruck forum,and I also found a proper manual for the motor online..........search for 600cc Mk 3 type 5,and you will find a repair manual,easily............if its been a starting engine,it will have badly brinnelled mains.......incidentaly ,the starting engines are impressive,you get in the back of say a RB54,big as a house,start up the JAP,and give it a bit of throttle,apply the clutch lever ,and the big Rustons just turns over and starts,no need to lift valves ,the JAP just plonks away,the white smoke turns to black,and the 6VPH starts firing evenly.......incidentally,the JAP is started by a belt.....a workmans belt ,that held up his dungarees........never lost,always available.
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Cheers, i'll have a look at that. Will attempt to post pics so stand by......
Right, well that didn't work. I could select the image from files okay and you can position it with the insert image function but i can't see any way of actually applying it. Am i missing something or is it just my +#x! computer?
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Hi Colin,
That;s an identical engine to the Howard Gem rotovator engines I have/ had, except for the head finning direction
Wide crankcase lugs and 90 degree inlet manifold are identical, that deep crankshaft nut is just like a spare one sitting on my workbench ::)
It should make an interesting thumper
John
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Incidentallly,the inlet pipe has a fine (26tpi)...LEFT hand thread.into the cylinder.
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The inlet isn't very sporty, think that will get a straight one.I was surprised to see the pictures up because i couldn't preview them so thought they didn't upload.I managed to download the manual mentioned by john.k and had already bought a Howard engine manual (paper one) off ebay. hadn't undone anything yet so left-hand thread noted! Plenty of penetrating oil on it now,especially on the exhaust thread. I know everyone has their favorite penetrating oil or cocktail of solvent and oil to shift things but the best by far that i've come across is Kano Kroil . It's not cheap but it really does work.It was the only thing that managed to penetrate all the crud on a splined pto shaft that wouldn't move on a tractor mounted cement mixer so i could replace the chain.
I was at Newark autojumble on Sunday and had a look at a couple of girder forks and a few gearboxes. I have to confess to never having had a "British bike" on the road ( have had British framed Scrambler and have got British framed speedway bike ) so my knowledge of British bikes isn't as good as it should be but i have partially restored/recommissioned a '37 500 MSS Velo, rebuilt an Le Velo and building BSA A10 engine for a friends custom bike. So with your combined experience what sort of gearbox would be suitable? of all the pre-unit boxes i looked at about half looked too small ( off lightweight Villiers etc ) some looked too chunky tho. It's not like it has massive HP but i'd like a neat "old looking" box with the primary on the correct side, also how many gears to be useable ? Any ideas?
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Hi Colin,
A Burman CP or BSA early B or M series would be robust and give 4 speeds
earlier hand change boxes are harder to find
Sturmey Archer boxes seem to be made of gold :o
John
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Burman CP with clutch is easily found,cheap too,and cheap spares............the catch with all the industrial JAPs is the driveside mainshaft is too short for a 4 speed box.............as mentioned ,a Sturmey LS is ok ,but ,pricewise ..........not complaining ,cause I sold a Sturmey LS ,two stud mount,w/clutch,but had a busted tooth on second,.....to a tosser makin a fake BS or Zenith, for $1000........thats right,1k Ozzie pesos........but still.....its kinda a lot to someone used to buy complete vintage bikes for $10
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Right, a bit more research required. Just looking around the Autojumble last Sunday there were a few boxes about for around the £100-150 mark. Couldn't identify all of them, there was a BSA one but the vendor didn't know how many gears it had! I did see quite an elegant looking Ariel one that was cast onto the bottom end of a twin but didn't look unit ( if that makes any sense ) could have been cut off neatly where the casting joined if it was up to it ( Arrow or leader ? ). Haven't measured everything up yet, just thinking out loud.
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Now is the time to start thinking. As you have to get both the primary chain and the rear chain in alignment plus provide means for adjusting both it's easier to buy a frame with gearbox still in it. This presents no alignment issues as does a frame from this, a gearbox from that and an engine from something else.
So, do your homework first and look for a frame and gearbox together.
If you don't go down the frame/gearbox combo track probably the cheapest gearbox option is a heavyweight Albion. In general Albion are unloved but with little effort can really come up to scratch. I recommend looking through the Hitchcock site and reading Don Morley's rebuilding instructions. Albion were used in many industrial applications so late ones are often found with hand change. Very vintage in character. Nor is it uncommon to find a three speed and reverse heavyweight. Useless in 99% of motorcycles but have their place in specials. Laugh at anyone wanting real money for an Albion.
Much research and thinking is required before jumping in further. All hours and hours of fun, fun, fun.
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You used to be able to buy a complete new Indian Enfield box and clutch for about 250 quid.....but I think all the cheap Enfield stuff has been cleared........The last project i built with a JAP engine was using a AJS ,mid 30s ,complete ish,but with no motor..............anything project with girder forks wheels and guards wont be cheap tho......Tanks are generally cheap for AMC bikes and BSA s,if you arent too fussy...........Any kind of panel tank will be dear tho,especially Ariel or Triumph......................expanding on the JAP mainshaft length........most bikes went over to 4 speed boxes around 1932/33,and at the same time fitted an extra ball bearing on the mainshaft to support the extra length needed to line up with the wider box...........another thing with industrial JAP sv s ,is a long straight intake wont clear a magdyno,and even with a plain BTH mag,you need either a long intake ,or mount the carby on its side......as was done with some bikes.......but Amal 76 on its side is problematic,as anyone with a Triumph single will tell you............incidentally your JAP would have had a Amal 225/3 carby,which is where the long arm floatbowls come from ,often puzzled over at swapmeets.
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Thanks for all the input so far...this is brilliant! I wasn't sure a classic bike forum would be that keen on a special with an industrial motor. I have to say the idea of building a special from scratch is very refreshing.I have restored modern "classics" to stock, am about halfway through restoring a Bultaco Sherpa with a few subtle mods and building an HRC VF400RK TT F3 replica ( from genuine HRC manuals ) .The Bultaco is quite straight forward and i have a list of known parts it needs, the Honda is a bit more involved because it uses different forks and wheels and most of the special HRC race kit parts it needs will have to come from Japan ( which isn't easy or cheap ). So although i want a simple looking bike it might actually exercise the old grey matter a bit and require some engineering solutions along the way.I've seen similar projects on the web where the builder has made the frame, it would be nice to have it exactly how i want it but don't really know how hard it is to get one through the SVA test. I'm led to believe the bike test is quite a bit simpler than the car one...............more research
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If you arent fixated on rigid frames......a donor Ive used is the Kawasaki KZ400 twin....this frame has sufficient room for a separate motor and gearbox,and Ive bought nice ,roadwrthy bikes for a couple hundred dollars........Otherwise ,if you want rigid,an Ariel single frame easily fits one of these motors............but nowdays is a bit costly.........girders will be a lot more.................now,Im not dissing you,but IMHO,the motor you have is incomplete,and youd be a lot better off with another motor thats complete...............If you keep your eyes open at swaps,you might pick up JAP OHV heads to suit.....all the ally bits are available as newmade and the motors convert easily to an OHV,which looks a lot better...........i once went into a mower shop,and was buying chainsaw parts ,and mentioned JAP stuff,and the guy had a lot of new spares for the Howard Junior JAP motor,..I bought the lot.
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Funny you should mention the mower shop, i was just talking to my neighbour about an old chap he got to sharpen a cylinder mower blade for him.I remembered him saying at the time that he'd been there for years and you couldn't walk around his shed for all the old engines laying about so i'll try and pay him a visit soon to see if there's any old rotovator motors. Another possibility is one of my best friends work for an agricultural engineers selling chainsaws/mowers/ride-ons etc and he's always out and about around farms and estates where he comes across the odd older bit of kit "waiting" in a shed. I have to speak to him anyway because my sister has just killed another ride-on!