OK-Supreme Motorcycles

Today in Motorcycle History

OK-Supreme Motorcycles

A Brief History of the Marque

Humphries and Dawes established the OK company in 1899. When the partners went their separate ways in 1926, Ernest Humphries established a new marque, OK-Supreme.

Prior to the First World War, OK motorcycles were fitted with De Dion, Minerva, Precision and Green engines. Subsequently the company fitted its own 292cc two-stroke and Blackburne 250 and 350 engines in both sv & ohv configurations. There were also 348cc machines with oil-coooled Bradshaw engines and JAP versions from 246cc to 496cc. The 248cc racing models were famous. Walter Handley completed the fastest lap in the 1922 IOM TT 250 class at 51.00 mph on a Blackburne-engined OK Supreme.

Example of a Bradshaw engine.



British Engine Builder
Fitted to numerous British and European motorcycles.
Bradshaw Engines


From the mid 1920s the racing bikes had JAP engines. An article on the 1926 Tourist Trophy Races in Motor Sport Magazine reads:

"The O.K. Bradshaw machines for the Junior Race are practically standard sports models as sold for £56, but have larger tanks and brakes and detail modifications to suit individual riders' requirements. The Supreme-J.A.P. machines were designed specially as T.T. super sports models, so that, although not yet in production, they can be described as standard models."

OK Supreme fitted their own 248cc engines in the early 1930s, retaining JAP engines for the larger capacities. Their OHC 250 took the IOM TT 250cc lap record in 1930, and this Lighthouse model was offered briefly as a road machine before the depression bit deeply and production slowed.

In 1934, new overhead cam models appeared at the Olympia Show. Available in 250 and 350 capacities for road, trials and racing, these continued in production until early 1939.

Among the last OK-Supreme models were ohv JAP engined high-camshaft versions with 248cc, 348cc and 498cc single-cylinder engines.

Although production ceased in 1939, a limited number of JAP 350cc racing machines were available until the death of John Humphries, the son of Ernest Humphries who was one of the two founders of OK, Humphries & Dawes.

See also: History of OK-Supreme

Sources: Tragatsch, IOM History, Motor Sport Magazine

gary.white451 at gmail dot com
1933 OK Supreme P/32
I have one of the above with 150 JAP engine and it appears to be very rare, if not the only one in existence. I see you show a sales picture on Sheldon EMU and wondered if you have any further info on the bike and also the source of your picture. I got a couple of press releases from Beaulieu, essentially just two pictures, and with your picture, that’s it!!!. I inherited the bike about 35 years ago and would like to restore it now I have retired with more time on my hands. I’d really appreciate anything you might have.
Gary White

OK-Supreme-1932-P32-150cc-JAP-GWh.jpg posted in Comments.
No further information on this rare beast has been found as yet.

3 april 2020
lionsden at netactive.co.za
OK Supreme
When did OK use the helmeted head tank transfer?
Tony Lyons-Lewis
South Africa

1938 and 1939, it is believed. See OK-Supreme Decals
bkibble1 at gmail.com
OK Supreme
Hi, I am wondering whether you can assist in identifying this bike.
The owner of the bike is my great grandmother. The photo was taken in the early 1920's in Preston, Melbourne Victoria Australia.
Brett Kibble
Brisbane Australia

Image posted in Comments.
san01178 at live.com.au
1913 OK Junior
I have inherited this motorbike and am looking to find more information for insurance purposes and, possibly, a view to sell.
Sandra Abbey
Brisbane, Australia Image posted in Comments.
colinmaz at gmail.com
Ok Supreme ?
Hi I am wondering if someone could assist in identifying (model,year) a basket case Ok Supreme that I have. The frame no. is 20364 and the engine no. (Jap) is F0S R44052. So from what I can find I believe it is a early 30's 250 ?
Colin Pedersen
missangethomas at gmail.com
1928 OK Supreme 350 SV
Good day

I am trying to assist my father in finding someone who can shed some light as to how the breather system works on his 1928 OK Supreme 350 SV.

This is his query: The two brass devices in the breather chamber do not move. Only one of the holes in the disc closest to the edge of the breather chamber is partially open to the crank case. I cannot see any oil being expended from the breather pipe. The breather pipe is higher than the opening in the brass hole to the crankcase. More oil seems to be forced up through the cam shaft than the engine breather. I am trying to find out how the breather system works.

see picture attached.

Much appreciated
Rod Thomas, South Africa

(Image did not arrive.)

rayanddenise at xtra.co.nz
I believe the bike in question is a 1929 OK Supreme
The bike has a burman gearbox with the part No or serial No G13H49 stamped on the gearbox casting.
Can you identify this box and do you have any parts??
Ray Whiting
New Zealand

This search reveals many resources on Burman gearboxes, though not specific to the OK Supreme. Search
No, sorry, we don't sell parts.

Sun, 17 Sep 2017
nfb_services at hotmail.com
1936 grand sportss GH j 36 engine GH 36 grand sports

Enquiring about this motor I have engine number is Pat 41248 is about all I can read of the barrell looking for any info history photos cycle parts any info will be greatly appreciated try and rebuild the old girl I have a restored mag not sure if it's correct please any help
Neil bailey
Perth western australia

  • There is a 1936 Model GH OK Supreme, could that be what you have? Any images you have of the machine may be helpful.

Yes I only have the motor magneto

Mon Dec 05 2016
petejesse at me.com
Wheels or hubs
Ok supreme 1930 ohv 350
Need a pair of wheels or hubs to complete resto

Thu Sep 17 2015
angelathomas68 at gmail.com
OK Supreme overhead cam: value and ignition timing
OK Supreme, 1935 350cc
Good day

I am trying to source information on behalf of my dad, Rod Thomas.

He has a 1935 OK Supreme 350cc. He needs information on the overhead cam. He is looking for the value timing and the ignition timing.

Thanking you in advance.

Angela Thomas
UK / South Africa

Tue Feb 24 2015
ricandlinda at hotmail.com
OK Supreme Snowdon Ranger
I have a 350 OK under restoration and need a pair of wheels or just hubs. These would have been made by Webb, Birmingham. The back hub has the drive on the left and the brake on the right. The front hub has a speedo drive. The rest of the bike is coming on well. Cheers, Ric.

Fri May 09 2014
alb4ker at btinternet.com
OK Supreme GH36
In process of trying to restore a 1936 manufactured bike. Require copt of technical detail from handbook to successfully complete restoration. Can you provide a source to obtain same ?

Fri Aug 24 2012
OK Supreme
OK Supreme G/32
I have just launched a website in an effort to provide more information about the Ok supreme. The URL Is oksupreme.comuv.com if you have any more information about the machines could you email me.
Oxfordshire, UK

Thu Nov 17 2011
OK Supreme
OK Supreme 1939
Can someone help me. Is there a book on all models of OK Supreme motorcycles. I have one I want to restore and can't find out any information on it. I need pictures.

Fri Aug 28 2009
alan at jt83.wanadoo.co.uk28ivw
wiring diagram<
ok supreme 1939 snowdon ranger
I am currently renovating the above mentioned OK Supreme and I think the wiring has been altered from standard at some time. I desperately need a wiring diagram in order to return the bike to standard. Many regards. Alan

Tue Jun 30 2009
mike at phsl.ukdot com
1920 O K 250 2 stroke m/cycle
OK 250 2 stroke
HELP! Any information would assist me greatly in my restoration project. I would like to see some detailed photo's of the handlebar arrangement and anything else you can tell me.
gloucester , UK

Sat Jan 03 2009
jeff.oaks at hotmaildot com
ok supreme
My great uncle Art Senior held the australasian land speed record on an OK Supreme. Could you tell me what year he did this & what year model the ok was. Also his regular race no. if he had one. He also won at phillip island and Bathurst's Vale circuit in 1934.can you confirm if this was done on an ariel hunter.
gold coast, australia

Tue Aug 12 2008
ssk at vtxmail.ch
OK Supreme Wheels
OK Supreme 350 ccm<
Search Wheels rear and front from a OK Supreme 350. 
Thanks Christop
Basel, Switzerland

Thu Jul 03 2008
foxwist at waitrosedot com
OK Supreme Lighthouse engine
I am trying to contact the person who exchanged a 500cc racing car chassis for a so called "Lighthouse" engine and bike frame some time in the 1980s with a Brian Dewey of Peakirk near Peterborough. 
Any help would be appreciated as we are building the cahassis into a car and are keen to trace it's history
Many thanks in anticipation
Roy Hunt

Sat Apr 05 2008
gantan at onvol.net
OK supreme with Jap engine
OK supreme
I need some help I have found a OK supreme with a small OHV engine ,its a basket case,but frame,petrol tank,guards, and forks are very good.the rest needs restoration.about 80 per cent complete.would anyone have an idea of what its worth .are these rare bikes.The guy is asking 1750 pounds sterling .would apprecaite your help please.Kind regards Charles

Sat Mar 01 2008
json.ulf at gmaildot com
petrol tank 1929
Am looking for an 1929 petroltank for OK Supreme.
I actually have pictures of a similar tank!

Fri Nov 09 2007
rogermarg at hotmail.co.uk
ok supreme flying cloud 1932
would be grateful for any help with valuation

Thu Oct 04 2007
json.ulf at gmaildot com
ok 1929
Does anyone have any info about what modell this Ok is?
Paper says 1929 500 sidevalve.
All kind of info is welcome!


Fri Sep 07 2007
rfhharvey at hotmaildot com
1939 O.K. Supreme 350 cc Jap engined
In 1966 when I moved to Canada, the above bike went "Missing" from my lock up . Plate #AUS 894 .Does any one know if this bike is still running.

Sat Jul 28 2007
goldwing643 at yahoo.co.uk
Motorcycle Sport Magazine PIC
1937 350 OK Supreme

I am having a clear out of 4 decades of Motorcycle Sport magazines I own and in the November 1976 edition there is a wonderful full page colour picture of a 1937 OK Supreme registration number DXL374. I can'not find an owners club for these bikes but was wondering if the owner/bike still exist and whether he/she would like the Mag for nothing. I am a restorer myself and know what it is like to have memorabilia particularly, of your own model. I am not looking to make money, I just thought it would be a nice thing to do. Should this note find an owner or a tip about how to locate the person then please reply.

Many thanks

Sun Jul 15 2007
ericthehorbol at yahoodot com
OK Supreme Motorcycle
1931 OK Supreme Lighthouse 250cc
Would like to correspond with other OK Supreme Lighthouse owners. My wife & I have 2 & would like to exchange information. Thanks. Eric & Teresa

Mon Jun 25 2007
becky at drawert.fsnet.co.uk
ok supreme silver cloud 250cc 1934
wiring diagram for coil ignition .particularly headlight/ignition switch

Thu May 31 2007
slaapstad at hotmaildot com
OK Supreme using BSA hubs
OK ?? - BSA C11
I understand that some OK Supreme motorcycles just prior to WW2 used the BSA C11 wheel hubs. Can anyone confirm this for me please??
Cape Town

Mon Jun 04 2007
chris-675 at hotmaildot com
1938 OK Supreme
I have the opportunity to buy a 1938-39 OK Supreme. I believe it was the only year model that had a 500cc Matchless engine. The engine, clutch and gearbox is excellent and its all there other than the magneto. Its very rough cosmetically and needs a thorough restoration and I was wondering if this bike would be worthy of the time and money needed to restore it back to its original condition. Any help in this matter would be greatly appreciated. Regards Chris.
Gold Coast, Australia

Wed May 09 2007
peter.jackson39 at tiscali.co.uk
query bike's suvival
OK Supreme 250cc 1933
I owned this 1933 250cc Jap engined Ok Supreme Reg. no.HV 2971 in the 1950s. Does anyone know if this bike has survived. I have one photo of it. Peter
Falmouth UK

Fri Apr 06 2007
bevkee at bigpond.com 
OK Supreme N34
Would you have any contacts who could help me restore my N34. Thanks Trevor.

Wed Feb 21 2007
salesqld at primosmallgoods.com.au
Humphries & Dawes OK
1913 OK
I have inherited a 1913 OK (last interim registration 1960) and was wondering about value for insurance purposes. My father was involved in the VMCC NSW for many years (1950's & 60's) and this was the only bike he kept.

Sandra (Brisbane, Qld Aust)

See the page on Vintage Motorcycle Prices

Mon Feb 19 2007
pearsonriley at xtra.co.nz
Ok Supreme 1937 Phantom<
trying to find information about this motorcycle. we bought at the same time as a T100, and haven't used it much. Its going to be turned into a classic racer, and has a 500JAP engine - koz/f [serial number /s

can any one direct me to more information about this model? i know it was never raced, at least not at IOM, however, with the sports JAP engine, it will have some decent legs.

also - does anyone know how many were produced?


Thu Jan 11 2007
pencad at bigpond.net.au
1938 250 cc flying cloud deluxe OK Supreme
Can anyone help me with information which will allow me to accurately restore this bike.

Mon Jan 08 2007
geordie.gonad at tesco.net
Please see atachments
Can yu helpme I'm tring to find some information on a OK motorcycle that my grandfather rode over Mount Helvellyn in the Lake District UK in September 1921 I will atach the only information I have a photostat of a paper cutting from the time plus a photo of him with the bike at the end of his feat, This photo is over 80 years old and the quality is poor if you can tell me the model or any info on this machine I would be very grateful the info I have sent you can be used by yourselves to show more of this marque.
Thanking you

Wed Nov 22 2006
info at eurobrit.com.au
ok supreme
rcb/321 ? silver cloud
I,m looking at purchase of a blue painted racer with bronze head-eng. no rcb/321.is this a 250 or 350-its cammy-not jap-thanks franc australia

Wed Aug 23 2006
force at accessus.net
OK Supreme Engines
OK Supreme mid 30's
Can anyone tell me if OK SUpreme were fitted with JAP and AJS engines around the mid 30's? Are these engines the same? Would appreciate any info or clues on where to search. Thanks, Raymond

Sat Apr 29 2006
dfroggattjam at aoldot com
I'm trying to find out where the ok supreme had there pemises in birmingham,i would be grateful for any info

Sat Apr 08 2006
the.abels at xtra.co.nz
OK Gladiator
I was wondering how much information you have on these bikes as my Grandson has just inherited one and would like to restore it, I'm not sure of the year of it .


Thu Mar 16 2006
Information for restoration
can any body assist me on any information with regards to a 1931 500cc jap engine ok supreme that I would like to restore.

Many thanks for you reply,

Stupidly I dismantled the bike a few years ago, which I have stored safely.
At that time all that was missing (I think) was the magneto, which I would think is pretty standard as there seems to be no trace of mag driven lights been ever on the bike.
My main questions are on what shape and form the bike should be restored in, and where would people recommend to put such things as the wheels for example, to be restored.
The engine requires assembly and its been that long since I dismantled it that I cant remember how to put it back togther !
Hope someone one can help ?
Regards John

Tue Mar 14 2006
jheijdennl51 at wanadoo.nl
O K motor bike
Hallo, Can you tell me more about a O K bike this bike has a flattank and tanktransfers with the name Humpries and Dawes with the year 1923 on it,a 500cc J.A.P motor,is ther a website that i can look,is chuc a bike expensive,what prices can i expect,is suche a bike Rare
greetings from the Netherlands H vd Heijden

Fri May 27 2005
cameronda at dodo.com.au
OK Supreme
Hello there
I have a 1935 Road Knight 600cc, after any info regarding this model or the 500cc Hood.

Sat May 28th
Here is a shot of the bike, they were sold as a sidecar only bike. But how it came to Australia could be different as apparently the sidecars were generally not imported with the bikes but one supplied locally, due to shipping costs. These were also basically a larger capacity version of the 500cc "HOOD" So a lot of the cycle information should be similar.

Currently I am chasing info through the VMCC of NSW and awaiting on the previous owner to detail his restoration. They have mentioned to me in the past that they have "Knights Head" symbol that apparently came from a sidecar which had been attached to an OK Supreme. This I am trying to get a reproduction one made if possible.

I am learning a bit about the bike as I go, one thing I should not forget is that the timing side of the crankshaft is a "left hand" thread.

Thanks for the interest
Dave Cameron

April 25, 2002
OK SUPREME OWNERS: Hello, I am looking to buy a mid to late 1930's OK Supreme motorcycle. I would like to make contact with anyone in the USA who owns one of these machines. I have some literature on this marque I would gladly make copies of for fellow owners. Bill Hooben, hooben at usa dot com

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