classic motorcycle forum

I agree Rex,there are many "Specials" out there,some not to my taste or possibly yours..But motorcycles and other vehicles have been converted and adapted since they were first madeFor me part of this hobby isnt just about whatever machine i may ride,but to me this hobby encompasses "all" aspects and I don't pre judge someone because they have a passion for Lambretta s,though to me personally they do not appeal!
I can appreciate a Brough Superior or such as much as a Bsa Bantam...
T he many early machines had their beginings using engines etc produced by others.J.AP. engines being a good example,they were used by many from Excelsior to Brough superior!
I am retired on a limited budget ,have had British motorcycles since the age of thirteen ,own a 51 500cc AJS ,a b31 /32which i ride regularly and grew up with a father and elder brothers  all riding British motorcycles.
Since buying this project i have spent many hours researching the J.A.P company their engines would often be the topic of  conversation my father held them in high regard,along with others he owned,Rudge,Matchless,many more I have forgotten ,Alldays&Onions being one i had to look up having never heard of them!
My late father race tuned (himself) a 1937 Triumph Tiger at Brands Hatch and was in the same races as John Surtees when he made his debut there,also mounted on a Tiger.
For me the "small investment "made buying this project was barely what "I " could pay for the Bsa c11 rolling chassis,which was what I bought the engine was an added interest.
I already have two engines which were made for this machine.
I am not naieve enough for One moment to believe that because the engine was made by JAP it is a racing engine,far from it!
It has the "look" of older machines and it will probably end up in my 1946  girder fork/rigid rear Bsa c11.....
It will give me hours of enjoyment just tinkering and doing " what I want" with my time and money!
It will be used and enjoyed.
It would be nice to see what machines the doom mongers on here own(if any?)
I feel sorry for those that are so fixated in their own ideas,they think anyone else's ideas are not valid .
The VMCC and other clubs say this hobby of ours is doomed as it is only the older folk interested,no wonder if like me they come on here and other forums , genuinely enthusiastic and seeking " helpful advice" from more knowledgeable
? people and  get pointless derogatory comments,perhaps those who run this site should consider this?
On a lighter note many thanks to the genuine enthusiasts that have passed on their "useful" knowledge.
I now know more about Pilgrim pumps and no doubt will be asking more questions,if my words are not for you pass by,it's what I shall do ....

For the curious !

Thanks Rex,it did come with a dating letter from the BSA owners club dating back to 2015.
But it must have had a standard engine fitted back then as it is a  different number?
I ll have to look into that in more detail,
Thanks David

Hi all,
Thanks for your input,as I mentioned previously my late father always spoke fondly of JAP engines he had owned.
I was offered a beautiful 're built 500cc Ohv engine complete with mag and carb several years back,but it's owner insisted he wanted £500( well worth the money)for it.Sadly at that time work was slow and my slightly lesser offer (400)was nt accepted,he said a " friend " was going to get him his 500 pounds.
Next time I spoke to him the " friend" Had told him  he only got 350 pounds for it.....
Hence years later my purchase of this as a project,it is a JAP engine albeit not the one I would have liked,but it is giving me something to play with!
I will post a few pics on here when it's looking a bit more presentable,as so far I 've just been getting it running better and checking the motor out.
The existing exhaust/stub? Is currently just pushed into the exhaust port and retained by a bracket welded to the pipe fixing to an engine mount bolt.It does seem to work so for now at least I 'll live with it.
I am hoping to get a straight inlet to replace the curved one and a stub fit 1"  Amal to suit,I have a few Amal carbs but they are bolt on and I don't have welding gear to alter the inlet to take them.
The other similar JAP engines I 've seen ,have a long induction tube to take the carb clear of fouling the mag.
Just another thought,would a different mag make any difference ?
Obviously the one fitted is I believe from when the engine was possibly  originally from an Atco 20" deluxe mower ?
Would a different mag (as used on motorcycles with JAP engines)make any difference?
It keeps me occupied and there is always a c11 side valve motor option,or a c11 Ohv bored out to 290cc using a Hillman imp piston....should keep my interest going for awhile!
Cheers

Yes,that's the one I found  ! Looks like I better start a fund?
 After seeing their prices ,that was what prompted my request if anyone has an old useable one they might sell?not worried about the finish as long as thread is usable .
Exhaust is 1 3/4" .
I had the head/ barrel off today,bore looks sound slight wear but rings and piston all sound.Plenty of oil evident,so I have reduced the pump setting as it s still quite Smokey.
Gradually increasing  the running time now i know the pump is working,hopefully turning clockwise on the pilgrim pump does reduce flow?  it seems to be running/starting a bit more reliably now.

Yes,I thought it sounded a bit on the large side!
I will check it out later ,thanks for your reply,David

Thanks 33d6 that information is very useful has been noted.
I have no expectations of breaking any speed records,just an interest and curiosity to try something a bit off the beaten track!
As much a part of this hobby is as you say not the destination but finding out and researching what it is !
Funny you should mention "Tuning for speed " I still have my father's copy and wish I were as skilled as he!
Once again many thanks for your help .
Regards David

Many thanks to those with" useful information,"as has been mentioned an Amal carb may be the easiest answer !(thanks Chater lea)
I have several so will look up what I have that may be compatible as the engine has inlet stub not flange.
Apparently Villiers owned JAP post WW2 and as far as I  can tell from the sparse information  ?the carb is correct for this engine.
I bought this as it has a nice Bsa c11 plunger frame 1954 (stove enammeled) ,forks,wheels etc in fair order even what chrome is fitted is sound.The four speed gear box selects gears nicely.
The engine is an Industrial unit as denoted by its "I" preceding the engine number I believe 1936 vintage originally fitted to an Atco "deluxe" 20" mower.
It is"as bought by me",I was not responsible for killing any machines or mowers,possibly I may( when I 've had  my fun tinkering )remember that ? even return it back to its roots (c11)
After cleaning the carb and adjusting the oil pump it does (now) run and seems to be moving oil.
Once again ,thanks to those  for your "helpful"assistance ,I will look up on the VMCC website ,as a paying member might as well enjoy the benefits!
Tragic ? Yes some really do need to lighten up!
Happy days