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OK Supreme sprint bike
#783538 09/05/19 7:59 pm
Joined: Aug 2015
Posts: 1,602
Likes: 12
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When buying spares for my JAP engined 1935 OK Supreme 250, I found a 1936 OK Supreme 250.
I decided it would be a good project to build a sprint bike styled along the lines of a '30s "Brooklands" racer. I decided that the Burman "H" gearbox would not be strong enough and it has a gap between 3rd and top big enough to fit another 2 ratios so I aquired a Norton "dolls head" gearbox at a very reasonable price. This week I bought a slightly stronger engine, a JAP 350 grasstrack engine.
It will be a very tight fit, I will need to space the rear triangles/lower frame to allow for the wider engine mounts, about 8mm each side. There is a slight clash between the oil box and lower frame rail, I may be able to resolve this with a custom made cover for the bottom of the oil box, I will need to make this anyway to collect the waste oil instead of dropping it on the track.
[Linked Image from live.staticflickr.com]20190905_203708 by Sigma Projects, on Flickr


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
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Re: OK Supreme sprint bike
Andy Higham #783539 09/05/19 8:17 pm
Joined: Aug 2015
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Dio has checked the engine over
[Linked Image from live.staticflickr.com]20190905_203628 by Sigma Projects, on Flickr


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #783540 09/05/19 8:22 pm
Joined: Aug 2015
Posts: 1,602
Likes: 12
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This is the inspiration for the bike


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #783541 09/05/19 8:26 pm
Joined: May 2013
Posts: 854
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Keep us updated, please, as you proceed.

Re: OK Supreme sprint bike
Andy Higham #784285 09/14/19 9:21 pm
Joined: Aug 2015
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Still in the planning stage,
If I make the front engine plates about 15mm longer, effectively dropping the lower cradle by that amount, the valve covers will miss the top tube by 6mm. It will mean engine out to set tappets unless I leave the covers off (no oil in there)
Thinking of the tank, OK Supreme racers had a cut away section at the lower right of the tank to clear the top of the engine. I do not wish to cut up a rare tank, so I will find a cheap common tank of a similar shape to cut up
This is what I mean about the tank
[Linked Image from live.staticflickr.com]fs_fs_7319325-267-1 by Sigma Projects, on Flickr


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #787513 10/19/19 7:33 pm
Joined: Aug 2015
Posts: 1,602
Likes: 12
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Not much progress.
I have determined the engine will fit with 20mm longer front engine plates and the engine as far forward as possible so the carb clears the rear tank mount. I have an AMAL TT carb and a 302 float chamber which I have found out is the rare 1 year only Manx Norton "weir" type. I have pulled the trigger on an Indian made BSA M20 fuel tank which is vaguely similar size and shape to the OK Supreme tank, it has cost £131.00 with free postage so no hardship to cut it up


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #787622 10/20/19 8:42 pm
Joined: Nov 2011
Posts: 370
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Nice project - - I need to graduate to some older stuff!


Life's uncertain - go fast now!
Re: OK Supreme sprint bike
Andy Higham #790612 11/19/19 8:02 pm
Joined: Aug 2015
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Likes: 12
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The bike came with half the top headrace missing. I removes the other part from the frame, it had been painted and I noticed chips on the edge
[Linked Image from live.staticflickr.com]20191119_185423 by Sigma Projects, on Flickr
The race is 1.6" OD x 1" ID, I bought a 51105 thrust bearing, bored the ID of one half from 25mm to 1" and turned the OD of the other half from 42mm to 1,6" It is suprisingly easy with carbide tipped tools
[Linked Image from live.staticflickr.com]20191119_185438 by Sigma Projects, on Flickr
[Linked Image from live.staticflickr.com]20191119_185452 by Sigma Projects, on Flickr


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #791009 11/22/19 11:59 pm
Joined: Sep 2019
Posts: 70
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Posts: 70
Elegant solution.

Re: OK Supreme sprint bike
Andy Higham #791557 11/28/19 7:48 pm
Joined: Aug 2015
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I made engine plates out of plywood then decided that metal would be a lot stronger!!
As the front plates need to be as slim as possible I decided to copy the original design and cut them from 4mm steel. I bought some steel off eBay and tried to cut it, the bandsaw just bounced off it, I tried a hacksaw, it hardly scratched it. I don't know what the fukc it is but it's not mild steel
I sat down at the computer and drew the plates using CAD now I can get them laser cut


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #793726 12/23/19 4:25 pm
Joined: Aug 2015
Posts: 1,602
Likes: 12
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George Brough used the Norton "dolls head" gearbox in some models, but as his bikes were "superior" the word "Norton" was milled off leaving an oval recess.
[Linked Image from live.staticflickr.com]20191223_155748 by Sigma Projects, on Flickr
As this is an OK Supreme and "Supreme" out ranks "Superior" I took it a stage further and designed an infill for the milled recess. This will be held in by a couple of brass screws after the cover has had a swim in the ultrasonic bath.
[Linked Image from live.staticflickr.com]20191223_155846 by Sigma Projects, on Flickr


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #793743 12/23/19 8:27 pm
Joined: Aug 2015
Posts: 1,602
Likes: 12
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T'other day I got my front engine plates from the laser cutters £10.85 for the pair including postage. I made some bushes with 5mm bores to press into the engine and frame holes and spotted through with a long series 5mm drill then drilled out to suit the mounting bolts.
Thanks to Malcolm at model engineers laser
[Linked Image from live.staticflickr.com]20191223_200401 by Sigma Projects, on Flickr
Next thing is the rear plates, they will be made from 8mm thick 6082-T6 aluminium (formerly known as dural)
The plastic pipe elbow under the tree is one of Dio's favorite toys
[Linked Image from live.staticflickr.com]20191223_200352 by Sigma Projects, on Flickr


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #793750 12/23/19 10:15 pm
Joined: Sep 2004
Posts: 1,307
Likes: 15
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Great progress Andy, where are you planning to ride on your first outing?


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: OK Supreme sprint bike
Andy Higham #793756 12/23/19 10:35 pm
Joined: Aug 2015
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I would like it to be ready for the George Brown memorial sprint at East Kirkby in August


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Re: OK Supreme sprint bike
Andy Higham #793805 12/24/19 5:15 pm
Joined: Nov 2011
Posts: 6,122
Likes: 62
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I'm following this thread closely because your starting point is the same as mine would be if I pulled a BSA B34 engine and frame off the shelves to build a special. I had considered doing that in the past, and even got to the point of piecing together most of a bike on a stand, before returning everything to the shelves. Anyway, I'll be very interested in the obstacles you hit and how you overcome them. Keep up the good work.

Re: OK Supreme sprint bike
Andy Higham #793879 12/26/19 3:22 am
Joined: Aug 2001
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Looks great, thats a stylish motor, cant wait.Runs on dope?

Last edited by gavin eisler; 12/26/19 3:23 am.

71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
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