Here are a few photos that some of you may find interesting. I am sure that most of you know that in the early 1980s Majesty produced two works bikes fitted with works Yamaha 250cc, OW10 engines (from the 1973 cantilever bike), one for Mick Andrews and the other for John Hulme. the bike that Mick andrews rode is well documented but Johns bike is not, so for the first time in nearly thirty years here are photos of Johns bike. It is now up and running and ready to be restored after being stored in boxes inside my old Hen house all of that time (1988) the bike is in original condition apart from the brake lever, tyres, cables, and paint.

I would just like to say a big Thank You to, 'Sam' Brownlee (Majesty`s team mechanic) who knows every nut bolt and washer on this bike, without his help this Topic would not have been possible.

Edited June 13, 201412 yr by ksmith

Wow, what else you got hiding in that henhouse?

I like the look of that clutch cover,its close to what I have in mind to have cast to get rid of the separate oil pump cover.Another little project to get around to....

Nice bike too.

The clutch cover is in one because the Works engine has no oil pump, the casings are sand cast in RZ5 Magnesium, take a look at these photos and note the straight cut primary gear with titanium nut and billet machined clutch basket, other titanium components include , the spring compression screws, clutch retaining nut, barrel studs, drain plug, all the small fastening`s and plate`s within the engine, the chain ring bolts and rear brake cam. Also the primary gear is on splines to the crank, and the crank in supported by 6306 C3 bearings (30mm ID- 72mm OD- 19mm W).

Edited May 29, 201412 yr by ksmith

Were the OW10 engines made for the cantilever mono shock bikes? Some superb one off bits used there.

Hope a restoration is planned & you ride it when finished.

Very good to be able to have a look inside an OW10 motor. Thankyou

Interesting about the splined crankshaft for the primary gear. The early Yamaha single cylinder dirt bike motors (like the DT-1) also have spline drive to the primary gear.

The bigger diameter main bearings are also interesting. What is the stroke?

That gearbox oil filler location would have been hard to access.

Yes this 250cc OW10 engine was from the 1973 cantilever bike, but it is worth pointing out that all other Yamaha Works Trials bikes ( what ever the model ) had there engines numbered OW10, they are all are very different, ( O= prototype W= works and the 10 denotes TY). note the clutch case and clutch cable on Mick Andrews OW10 cantilever bike below. About ten (250cc) engines were made for the cantilever bike but only a few have survived, at a glance they look like TY twinshock engine`s but none of the components are interchangeable they are one off`s. The barrel is the Majesty S type only used on the Majesty Works bike`s it is a TY barrel bored to 74 mm and re`sleeved with new port timing, the finished bore is 70 mm ID with a stroke of 63 mm. Please see the photos below.

Many thanks to Mr Clay Seltzer (vintageworksbikes.com) and Mr Torsten Hallman (four times World MX Champion) for explaining the meaning of Yamaha works numbers.

Edited June 15, 201412 yr by ksmith

Great Pictures Keep them coming !! its not often you can see a genuine works bike .

Regards

Edited April 20, 201412 yr by scorpa250

Very nice(unobtainium) but it looks quite different to the OW10 engine in Craig Mawlam's Kato special

Edited April 21, 201412 yr by jc2

I have never had the chance to compare my engine with another, it would be nice but very unlikely, here`s a photo of the engine number and frame number (the frame has since been glass blasted).

Edited June 13, 201412 yr by ksmith

E-number

E501

Name

Potassium carbonate

Function

pH regulator.

Foods

Baking powder, baked products, cocoa, chocolate products.

Description

Regulates the acididty of foods.

Here is a photo of one of the engine bolts, they are all the same just different length`s, individually turned in Titanium, note the feed marks and the end centre. there are lots of talking points about this bike and I have lots of photos. Just ask.

Edited April 21, 201412 yr by ksmith

Is the clutch arm still underneath

No the clutch arm is on top, here are some photo`s from the rebuild.

Edited May 1, 201412 yr by ksmith

Wow! Thanks for sharing photographs of this rare motorcycle