JAP 4B Racing Engine For Sale

                                                                  J.A.P. 4B Engine

On offer is a J.A.P. 4B long stroke racing engine from a parts stash out of
the Midwest Cooper F3 racing fraternity.

The engine was pulled from a racer years ago to be rebuilt for a new race
season which, for various unknown reasons, never happened.

This is the same 4B engine that was run in flat track, dirt track and grass track motocycles.

In preparation for the rebuild the case was cleaned and the inside coated
with red glyptol and the outside was given a spray of gray for corrosion
control on the lectron/magnesium case. The engine has had the flywheel and
main bearings fitted along with the con rod.

All other parts have been dry fitted before final tolerance and proper
honing and fitting.  The engine has no seals with it and must be considered
a complete but unassembled engine.
The parts provided are as follows;

  Glass beaded steel head
  1 1/4 inlet track has a good nut and carb flange which has been blended
into the head intake port but not polished.
  Good threads on exhaust outlet and chromed exhaust nut with a nice
smoothing of the exhaust port but not polished
  New Titanium valve spring caps and keepers
  New stainless steel valves - 1 ¾ intake - 1/1/2 exhaust
  New valve springs
  New steel valve guides with the option of alum/bronze if desired
  Valve rocker and bushings with needle bearings are original equipment in
good condition
  Complete rocker box with a small crack in the bottom edge of one rear
spring cap
  Oil line from pump to rocker box and secondary feeders from rocker box to
valve guides but oil pipe unions will have to be sourced for the build
  Lodge Pink spark plug (SL51?) maybe just a place keeper
  New Carrillo H-Beam rod
  New 80mm Arias domed racing piston with rings
  Case cleaned and coated for corrosion protection on the outside and oil
shedding on the inside
  Wellworthy ALFIN barrel- good fins and good clean steel sleeve
  4 compression studs for head to case - good threads - stud appearance fair
but useable
  Pilgrim oil pump - used but on inspection appears good
  Oil box has in place four oil return valves
  Polished roller valve lifters
  Valve cam with unknown profile
  Flywheel has been polished and balanced - unknown balance percentage
  New alloy push rods with good ends
  Chromed push rod tubes
  Magnesium timing side cover, oil box cover, oil return box and magneto
stand
  SEM magneto which sparks but has not been tested and needs cleaning and
new points cap
  Drive side splined carrier and retaining nut for drive cog
Unknown maker bronze mechanical tachometer drive to run off the magneto
shaft with cable drive end which should, with appropriate cable, drive a
Smiths Chronometric tachometer

Engine has been dry assembled only for the purpose of checking parts fit and
inventory of parts.  This engine has not been built as it is excess to my
requirements.  What would be required is cleaning and fitting of all parts
to specifications.

My Overland cycle needs only one engine and so this engine which as they say is excess to my needs has to find a new home.  I would very much prefer it go to a home that will run it.

Anybody with an interest in this engine please leave your contact information as a comment and I will get back to you.

                                                       The simplicity of the J.A.P. 4B

This is a photo of the for sale engine before dry assembly to check that everything was there.

Thoughts about materials

I’m old enough and had an interest long enough in things wheeled both petrol driven and calorie propelled to have experienced and read a great deal.  I have read books and available magazines for years.  Found and read obscure books of metal fabrication, manufacturing techniques and vehicle design books and articles.

So as regarding my project of the Overland and how all of the basic bits will be hung together to actually be the Overland TT privateer racer these are some of my thoughts.

For my purpose cycle parts are all of those things other than the engine, drive line and wheels.  And as I ‘m very cheap but hide that behind wanting to be green and recycle and reuse when possible most of the Overland cycle parts will be adapted from other bits and pieces of things.  The fenders will be cut down from beat up alloy trials fenders.  The fuel tank and probably the oil tank will be panel beat from old Land Rover Birmabright alloy.  The headlight and tail will be fabricated from and old SU fuel bowl and an SU carb cover.  The thumb throttle will be made one of two ways; fabricated from the bronze cam lever of an old AC fuel pump or modified from and old alloy choke lever.

The frame and fork to provide something to hang all this stuff from will be of my own design.  I’m not a design genius.  I just research really well and don’t have any probably borrowing an idea here and there from the design genius’ I come across.

The frame will be gas welded using new aircraft grade normalized 4130 chromoly steel seamless tube.  I have looked at all of the pro and cons of gas welding the frame; done the due diligence research and for my application and wanting to do it myself in a cost effective manner, gas welding is the way to go.  I figure if you can build an aerobatic airframe gas welding the tubes and have the FAA approve it as airworthy then it will be fine for my Overland.

The basic idea will be a hard tail frame using the gear box and engine as stressed frame members.  Then create as many properly triangulated frame structures around the first main frame triangle, I should come up with a strong and rigid frame at a very minimum weight.  I will be using a great deal of ideas from the motorcycle racing community and the mountain bike community for the overall geometry of the frame. 

What I want for this frame is it will be light weight, rigid and mechanically strong.  Will have handling which the engine will not be able to outperform and be better than I am as a rider.  Stability at low and high speeds will also be a consideration.  I don’t like twitchy mountain bikes or motorcycles.

Of all things I have mentioned the welding will take the longest to complete.  Because I can’t say I’m a gas welder.  I also have never successfully welded Birmabright.  Both 4130 welding and alloy welding are what I will be learning.  An upside to this lack of skill is a good deal of off-cuts and panel trims to use while learning.  So I will be burning through alloy and tube over the next few months. 

The quality control on the frame tube welding will be checked by a good friend who is a vintage aircraft restorer and has many years of experience with both motorcycle frames and airframes.  He thinks I’m nuts to want to use gas rather than MIG/TIG because of how much faster MIG/TIG are.  Unlike him I don’t have to justify hours of work to the customer because I am the customer and I’m not charging myself for labor

The reason for using 4130 needs some explanation of a sort.  In all my reading and research some of the lightest and most competitive motorcycle specials used Reynolds 531 tubes.  The same goes for mountain bikes.  Of course time has moved on and that today is not true because of the increased use of aluminum, titanium, carbon fiber and high tech steel.  But I have never been accused of being overly concerned about what is current or new or hot.  I can’t afford real Reynolds tube.  But I can afford 4130 which is in reality just a hair breath away from having the same metallurgical mix as 531.    

In this entire project one thing that is always in mind is safety.  As a result of several life experiences with the military and just living in general, I don’t particularly fear death anymore but I also am a chicken and don’t handle pain very well.  So I really want to be able to enjoy the fruits of my labor rather than have it kill me by my own stupidity.  So safety in the garage and safe design and construction methods are always at the top of my list.

The heavy box that puts power to the rear and onto the road

I was very blind lucky and stumbled onto a pretty good condition Norton Atlas gear box.  I was looking for a BSA pre-unit A10.  But the Norton came my way and in, I hope a bit of karma, it was good.  The Norton box is smaller and has two very substantianol mounting lugs.  Plus, I noticed it has a decidedly egg shape to it that will allow it to nestle right up against the engine case and help control the center of gravity.  And of course with the gear box and engine being  coupled it should contirbute to the rigidity and overall strength of the main triangle of the frame without adding lots of extra steel. I have also noticed, from peeking at other builds, that the Norton can be rotated around quite a few degrees before you start having trouble with kicker and shifter fouling problems.  I'm not contemplating anything radical but it's nice to have scored a box that has that proven flexibility in mounting choices.

I will be looking for a replacement clutch adjust cover plate which has Norton scribed on it.  I have seen a few but never run across one yet.  But I haven't really looked hard either.  I don't want to hide the provenance of the bits I use.

And after all, if the Norton Atlas box is good enough for Big Sid and Matt Biberman to use on their Vincent Comet build, Overtime Tina, well it should work fine for my Overland.

Rubber on the road or the big round bits for the Overland

                                          Right side of rear rim and hub

                                         Left side of rear rim and hub

Well I have recorded some of my thoughts about inspiration and a semi-vague reasoning behind doing this.  So I should introduce the other major bits to be used on this build.

The wheels I have chosen are from a Honda 450.  Not sure what model or what year.  However they are from the same cycle and are the wheels I have decided will work out.  The back is 18 by 3.50 and 40 hole full width hub.  It's currently laced on a steel DID rim with single butted spokes.  It is not the lightest rear hub and wheel out there but it met all of my conditions and was available locally, well 100 miles away and for Montana that is local, and cheap.  Parts for the Honda hubs are also still very available and it seems that some very good racing compounds are available for upgrading the shoes.

The front is basically the same but is 19 by 3.25.  It is a twin leading shoe brake drum.  That reportedly is very effective when set up carefully.  It also has a DID steel rim and single butted spokes.

I would have really like to have gone with 19 inch front and rear but that will have to wait until I start searching for replacement alloy rims.  I will try to find an alloy rim that has the same profile as the DID rims, only because I like the looks of that older style rim.

Now if some Akront shouldered 40 hole rims happen to drop in my lap I won’t toss them out.  When I start drawing up and prototyping the frame I am going to see if I can build the rear triangle just a hair bigger so I could go to a 19 in the rear if I find the alloy rims.

Also along the way I will be drilling and cutting holes in these hubs for a front air scoop and ventilation along with a similar treatment for the rear hub.  Is it necessary?  Absolutely not!  Will it take off a great deal of weight, which will make a large performance difference?  Absolutely not!  But it will make me feel like it’s enhancing performance and it will look COOL!  Yes there it is, an admission of style over substance. 

                                         Right side of front rim and hub

                                          Left side of front rim and hub

Weight

In motorcycles and generally any wheeled vehicle driven by an engine or a human, weight is the enemy of speed and efficiency.  The lightest weight consistent with strength and function is a driver for this build.

Two Wheeled Inspiration

I have never been attracted to twin cylinder motorcycles.  I greatly appreciate the look the sound and the mechanical variation of twins but they just sort of leave me cold.  Cold, in that I never developed a desire to own one.  I can’t remember if I’ve ever been tempted to ride a twin.  Just as a certain simplicity and style of design and craftsmanship has attracted me to some cars the same is true for my two wheeled inspiration.  Most are J.A.P. engine small production bikes or racing specials.  And some will be twins.  Each one has elements of design and fabrication that have attracted my eye or in their total presence are just plain cool. 

The first motorcycle I saw that used a J.A.P. and really sparked my interest in building my own special with an Over Head Valve engine was a 1926 Brough-Superior.  Not your typical twin Brough-Superior.  But the one and only single cylinder racing Brough that ever rolled out of George’s garage.  I ran across a mention of a single Brough some time ago and made an inquiry to the Brough-Superior Club regarding the bike and if it still existed.  The answer was yes with a short bit of information and three photos.  No indication of who owns the bike or if it is even run on a regular basis.  It obviously has been rebuilt and there is one photo around of it being ridden at some field meet.  I can only guess the bike is in the UK.  I do wish I could talk to the owner.  But unless somebody knows the bike and is willing to share I probably won’t ever have that chance.  The bike has a stance and a minimalist style perfect for a racer.  The use of the twin port head presents a very strong sweep of pipe on both sides of the bike.  I have read that the J.A.P. twin port was never really a very good head in terms of performance.  And the engine has the old style dog ear valve train.

This is a wonderful O.E.C. of unknown age and I can’t remember from where I nicked the photos.  What was interesting to me about this bike is the use of the race engine fitted with what appears to be a bronze head along with the large fin ALFIN barrel.  It is possible that this maybe an example of either a privateer order for a grass track bike or an attempt by the factory to be competitive in that area of racing.

This is a 1937 OK Supreme which without a doubt has a five stud race engine and it is licensed and run on the street on methanol.  And this bike I may get a chance to correspond with the owner.  We shall see.  It’s just all in all a lovely bike from the color to the stance to the fit and finish.  These photos are courtesy of Keith Marshall from the J.A.P. Engine page on Face Book. http://www.facebook.com/#!/group.php?gid=262038688796

I have to remind myself to keep track of where I nick photos.  Not providing attribution is very rude and I apologize.  I can only say in my defense that I am always so taken by the image of a fine motorcycle that I forget my manners.   This is a Crocker single and is there anymore that needs to be said?

The Engine

This is something like what the engine of the Overland will look like.  Classic J.A.P. OHV with a magnesium case and timing gear side cover with magneto stand. The barrel is ALFIN aluminum with a steel liner and big fins for cooling.  I will not be keeping the drive box for a chronometric tachometer.  In its place will probably be an auxiliary scavenge oil pump.  After all this is a racing engine and it is a total loss oil system.  I don’t think many people would appreciate oil from my race engine just dumping out on the road after it was used once through the engine.  There is still a performance question in my mind regarding the hair pin valve springs.  They do have a certain style and supposedly the size of the spring helps in cooling the engine.  Of course with an air cooled engine, keeping things cool is always good.  I have also read of problems with valve float using the hair pin.  I do have a set of double coil valve springs in the spares box just in case; along with  a complete set of proper valve covers for the springs and valve side rockers.

Inspiration

My inspiration for this Overland J.A.P. comes from vintage automobiles, mostly sports cars and racers.   It also comes from vintage motorcycles and the privateer racers from the 1930s to the 1950s.  A large douse of inspiration comes from the small independent motorcycle builders and restorers currently working in small sheds and garages all over the world.

So for the idea of using a racing engine in a road registered motorcycle rather than tuning a generic production engine came from Bugatti, specifically a 1934 Type 57.  I have read of the Type 57 being described as just a barely civilized Type 35 racer.  Or put another way; all of what Bugatti learned in racing was used to make the Type 57 the highest quality race proven touring car ever offered to be used for high speed road work.  So when I had the opportunity to snag a J.A.P. Over Head Valve 4B racing engine and run it on the street in a road cycle; that inspiration came from the Type 57.

Images from Bring a Trailer from a For Sale posting.

There is nothing rational, or logical, in building, from scratch, a motorcycle using an unusual old British single cylinder racing engine.  The entire project is an emotional response to years of messing around rebuilding a few things such as bicycles and Land Rovers but never seeming to scratch the itch to build something which is original. 

 
Original in the combination of parts and how they are put together; the basic form is old.  It is the creative combination that will make it original for me.  I also find that the opportunity to use years of skills in mechanics and metal working and acquire new skills is also a basic reason for the project.  It’s an effort that will keep my mind and hands busy for the foreseeable future. 

In addition it’s a physically real two wheeled fiction novel which will have a past which will be created and attached to the cycle as I build it.  Everything from the fictional cycle company of Overland to the racing history of the engine and the tale of how it was rescued and put it back on the road will be a fiction.  Yet the cycle with quality work and attentive detail will be real.

I’m pretty much a Luddite when it comes to cycles, motorcycles and cars.  I wasn’t even dreamed of when hot rods, choppers, cut downs and shed brewed racers really hit the big time in America.  A small peek into history will reveal many privateer racers tuning, tweaking and squeezing the last bit of speed out of anything with an engine and two or more wheels.  During the end of the fifties and in the sixties I was too young to drive but had plenty of dreams.  I use to mow my neighbors grass in the summer when he was away driving long haul trucks.  I also got to daydream sitting in his 1954 Pennant blue Corvette.  I was all of maybe twelve years old.

There wasn’t a single book in the school library or the public library I had not had in my hands.  I didn’t help keep me away from internal combustion powered vehicles when my father was as interested as I was. But being a school teacher and raising three kids didn’t leave much left for anything other than appreciating and dreaming. 

I remember a friend from church dropping by the house every once in awhile driving a black MG-A twin cam.  In grade school a class mate’s father had a MG-TD and a Morgan; both painted a cream yellow.  Much of my growing up was spent reading hot rod magazines and early motorcycle magazines along with any car magazine at the local news stand, when I didn’t get caught by the stand owner.  I would dream of all sorts of road machines and flying machines.  But it wasn’t always just about moving by burning petrol.  It was also about the style, grace and beauty of a well thought out design and the execution of that design with quality.  I knew the difference between a Cord and a Packard long before I even knew what a constitution was. 

All of the great British automotive names I knew.  I even knew many of the great European manufactures names.  The Bugatti horse shoe shape was too me the ultimate and perfect house for a radiator; right up there with the Rolls-Royce and Flying Ecstasy.  The smooth and blended lines of the nose of the racing Jaguars was primitive and captivating.  The long hood and sweeping fenders of the Packard’s was mesmerizing.  And before I realized what sexy was the Italian machines

I could spot a Harley or an Indian.  I could tell the difference between the exhaust note of a British and a Japanese motorcycle.  For anything two wheeled, I could almost tell you, from just the sound, if was a single or a twin; four stroke or two stroke.  But time went by and things like girls and bicycles and just life in general became more important.  But I never forgot. 

I watched as the European firms and the Japanese auto makers started whittling away at the America manufactures place in the market.  Cars became more fuel efficient and smaller.  Safety became an issue as did reliability.  By the end of the seventies cars, domestic and foreign cars started looking a lot like each other.  I started seeing what I called the Hot Wheels era of automotive design.  I’m sure that phrase is not original with me. I lost interest in the latest new cars.  Unfortunately cars became a tool to help raise my own family and anything other than just transportation was not affordable nor did I have the time to waste on something like an old car or motorcycle. 

So for me and my odd little world anything newer than the late sixties I am not really interested in.  I can appreciate the latest in automotive engineering but if I had a multi million dollar lottery ticket in my hand nothing on my list of cars to buy would be newer than maybe 1965.

However I was able to during the eighties I was able to sneak in an old 1962 Land Rover.  How that happen I don’t remember.  But it always ran and was easy and cheap to keep running.  Since we always only had one car and I commuted to work by bike, it was an acceptable time waster.  And I still have the Rover and it still runs reliably. 

Several times I tried to get into old British motorcycles but failed miserably because something just never clicked for me.  Maybe I felt to inhibited trying to keep things working and bodge something that was a luxury and if it broke would be costly to fix.

I’m not sure what it was.  I just never had the feel and very much never felt I had the license to just make do and do things to the cycle my way.  There was this invisible taboo in my head about just doing what worked and realizing that it really didn’t make any difference as long as I liked the result.

That mental brick wall no longer exists for me.  And as a result I’m building my own motorcycle from scratch and keeping alive my first bobber motorcycle along the way.  Both with J.A.P. engines.

It would seem to me that an explaination is in order regarding the masthead of this notebook.  The bicycle head badge is from a very small bicycle firm trading under the name Overland.  The conccern apparently built cycles in the mid-west of America in the early 1900s.  I tired to find either an old add or a surviving example but failed.  I may have not looked in all the right places.  While the firm is long gone, one of their head badges survived.  Overland cycles will carry on, at least, on the head tube of one more two wheeled cycle.  However the difference will be the new Overland will be powered by a motor and not by cranks.   And as a clue to what the power unit will be, the timing side cover of a J.A.P. engine is included in the masthead.

J.A.P. was a British engine builder from the beginning and in the glory days of British cycling.  J.A.P. engines actually had a presence in motorcycling world wide.  John A. Prestwich & Co. built engines ranging from small two strokes to large displacement V-twins.  They supplied engines to the Rolls Royce of motorcycles Brough-Superior and the small obscure French firm of Dollar Motorcycles.   

If anything this notebook will be used to record my attempt to create a fiction of a J.A.P. powered Overland Motorcycle; MADE in U.S.A.  To make that fiction real in the form of a running motorcycle.  And since it’s my notebook I may diverge from time to time and leave pages blank or rethink and tear pages out.