Cylinder Head

In Mick Walker's book it shows this type of head fitted to the 1960 models. However i thought the earlier Dominator head looked more Regal/stylish with it''s perpendicular Exhaust port finning!

John

Sorry guys, the last Screenshot of the upright engine I was just displaying the old type cylinder head it is not mine, but the whole engine is/was on sale on Evil bay!

My engine was the first 3 Screenshots!

John

Okay I started stripping down the engine and came to a halt because I need a super slim box spanner or socket for  the deep in the fins cylinder head bolt  and nuts!

Had to rotate the engine, so had to look under the Timing cover, had Anna on the mobile, giving me advice and direction.

Also I will need a puller for the Timing side half-time pinion & intermediate gear sprocket! I think I have that right. But look both my Timing chains have Spring Links on them, has someone been very naughty here! I thought these chains were supposed to be endless!

Plus the punch marks on the sprockets are not aligned they are about 30 degrees out as in one at 12 o' clock and the other at 5 minutes past 12!

And then I measured the Perpendicular  Inlet ports than seem to have a diameter of bang on an inch, good for gas velocity, (narrower ports), but will they flow enough air through for the 600cc engine, shouldn't the ports be 1 1/16 inches, or is the head from a 500? Or Scrambler model?

Incidentally, why did they change the port mounts from vertical to Horizontal, spacing?

John

See Here:

Funnily enough I was wondering about the swirl effect on gases and  how ports particularly on Singles used to be to off-set to increase gas speed and mixing of air and fuel to enhance combustion!

Not for nothing did I burn the Midnight oil in the 70 & 80s, reading Phil Vincent's Motorcycle Engineering and Tuning For Speed,  On a Summer's Eve my Father used to hear my BSA single decelerating and changing gear for the two round-a-bouts when I was  coming off the M61 @ Hartwood Park, Chorley and I still had a mile to go up the A6 to get home! What innocent times they were!

No longer could I park round the corner to let my engine cool down, like I did on my D10 4-speed Bantam, because he use d to sneak into the garage and feel how hot my engine was to see if I was thrashing it and all the time he thought I didn't know!

Speed camera's were still in someone's imagination for a dull dystopian future!

John

Thanks Robert, Okay, are 1" Inlet ports standard and have no need to be enlarged?

How dangerous are Spring-link fittings, have anyone seen that done before?

Initially I want to concentrate on building a strong engine, the rest is secondary, as the engine is the heart of the plot!

John

Hi Lionel, smaller bore pipes within reason, that is; that they are not too small for the job to be done, allow for higher gas speeds and faster  air flow, for the inlet tract and spent gas to exit from the exhaust port.

Gases are "fluids" and the best way to think about them is as in water-flow,  in fact that is the best way to think about electricity too! Engine efficiency is more about gas flow speeds and surprisingly large bore sizes  in carburettors and exhausts can reduce dramatically an engines gas flow efficiency with the resulting loss in mid-range power therefore making it's performance, less flexible for the road.

With a Racer, Largest carb possible and largest bore exhaust pipe, again within reason for gas flow dynamics but Racing bikes  have to operate in the high RPM zone virtually all the time, but again the sizes and lengths of inlet tracts and exhaust systems has to be factored in.

A step in the Inlet tract would probably do more good than harm, as it gas speed agitation and the swirl effect. I think it was Freddie Dixon who either working on Riley's or at Douglas at Bristol accidentally found a partial blockage increased bhp and efficiency in the 80 plus 90 plus days of the 350cc horizontal twins. Imagine to Norton's horror a  fast Douglas 350 cc flat twin, blowing off their 497 cc twin!

Leo Kuzmicki was the master of tuning efficiency in head design and engine output. He worked at Norton,  then Rootes, Hillman Imp and maybe Jaguar.

If I fitted 32 mm carb's on either my 592cc or 398cc Kawasaki Fours, they would be slower and less flexible than if I stuck with the standard 30 mm options! But people do change them, thinking the bike is going t be faster through the rev' range, the fools!

John

Lionel, I suppose changing cylinder heads was common practice in the day, if an Owner thought a better head was on the cards and available,  swapping to twin carb's too would have been seen as an upgrade. I am not sure how long the Triton/Rocker phase was about, I was a kid in the 60s, but around then I suppose there was a demand to make the bikes go faster. It would be interesting to know how many bikes were left bog-standard in this era.

All down to available money & marketing persuasion, no different today I suppose, except that under the new political regimes of  the Euro air=pollution, CO2 output demands and ECU's and all that they no longer want to permit Owners to take an interest and fiddle with their machines, unless you pay money to a bloke to run a diagnostic software program and illegally fiddle with the ECU inputs and controls. Sealed engines was their dream, Euro-politicians in the late 70s, Bike Magazine, did an article about German TUV and impending "type approval in a Autumn 1978 issue!

Robert, I try and get good original second-hand stuff if I can, rather than, Fake "like" replica stuff ! I notice there has been a clamp down on Ebay, re people claiming that replica stuff was made by the original companies. How many restored machines are full of fake replica stuff though? Better to start off with a tatty original and work from there, in my view.

John