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Perfidious Albion


vibrac

Well Known and Active Website User
VOC Member
I am having some difficulty calculating the internal ratios of my Albion Box in a form normally accepted and shown in books. In the past like many others I just read the ratios from a book and calculate speeds via sprocket ratios and chose accordingly but of course with an Albion box who knows what I have.

I thought it would be easy count the clutch shaft turns for one turn of the gearbox sprocket and express the result with top as unity 1:1 hoping for a result of say1:1 top, 1:2, 1:5, 2:0 bottom
However (with the box detached) in each gear I get :
For one turn of the gearbox sprocket shaft the following turns of the clutch shaft(approximate)

Top 1.75

Third 1.33

Second 1.2

First 1.0

Or (and this is one of the things not clear to me) it could be expressed as turns of the gearbox for one of the clutch (reciprocal)

Top .57

Third 75

Second .83

First 1.0

Assuming it is the first method and expressing top as unity I get

Top 1:1 third 1:1.3 second 1: 1.4 bottom 1:1.75

This is clearly wrong or I have a strange set of ratios….
 

highbury731

Well Known and Active Website User
VOC Member
I am having some difficulty calculating the internal ratios of my Albion Box in a form normally accepted and shown in books.

... expressing top as unity I get
Top 1:1 third 1:1.3 second 1: 1.4 bottom 1:1.75

This is clearly wrong or I have a strange set of ratios….
The accepted method is your last one.

If the ratios are correctly calculated, you do indeed have an odd ratio set. With the other ratios, you would expect third to be somewhere around 1.1:1 or 1.15:1 Best way is to count the tooth numbers and multiply it out. There may be an Albion third gear ratio pair which can give you a suitable result.

Paul
 

davidd

Well Known and Active Website User
VOC Member
I can't do the math, so I do it this way:

Albion Ratio Chart.JPG
AlbionHTT031.jpg

Starting with first on the right, then bottom to top: 29/19, 24/24. 22/26, 20/28 which means this is a No. 5 box. This would be the usual Grey Flash ratio for the non-KS magnesium box. The aluminum No. 16 box was provided for KS Flashes. What shows up at flea markets could be anything.
Credit goes to Jim Richardson for the lovely exploded photo.

David
 

vibrac

Well Known and Active Website User
VOC Member
Thanks for that David I must strip the box and start counting but it does look like the first gear pair is my problem. I note that both the K/S and non K/s boxes first gear pair both add up to 48 and I do have a couple of K/S Boxes I got before I found my racing box when I was contemplating building a racing box replica (I think it could have been done with some welding as I have a small racing outer cover) .However since the kick start is obviously next to the bottom gear pair I suppose they may be different in design so I may not be able to swap a K/S pair (18/30 or 17/31)into my racing box, the other thought is Enfield gears although the tooth form/pitch may be different they work in pairs and after all its the PCD that matters... Enough I must strip the box.
 

vibrac

Well Known and Active Website User
VOC Member
Hold on -see what I mean about perfidious! the tables go Ratio side 4321 Gear side 1234 so above that should read K/S pair(31/17 or 29/19)
To add to my confusion I thought the outer pair nearest the kick start were the (1) bottom set:confused:
Also amend the comment "strip the box" to "strip the RH side of the bike then strip the box":(
 

vibrac

Well Known and Active Website User
VOC Member
UPDATE
I have stripped the box and on the layshaft starting at the drive end I have 21 24 26 28 which using the table supplied by David gives me a No 3 box
to make it a No 5 box I shall need a 29/19 (some hope!) I note a 'standard box' is 30/18 which if I have got things the right way round is a little lower at 2.78 than the No5 at 2.13*. So now I shall raid my store of Albion boxes and strip one down to see if its any good (I will be getting good at working on these boxes soon...)

* That wont be too bad because of the stupid chicanes they have added to the UK circuits to slow down the super bikes which the ACU in its 'wisdom' force us to keep for reasons unknown to man for Historic racing as well.
 

roy the mechanic

Well Known and Active Website User
VOC Member
Vibrac, the reason we have to use the chicanes is down to the a c u. Each circuit has to have an a c u certificate, If you remove them it becomes a different "circuit" and requires a second cetificate, the folks that do the certification just won't be bothered with it.
 

tatty500

Well Known and Active Website User
Non-VOC Member
Surely top is 1:1....i.e. direct drive.....one turn of clutch for one turn of output sprocket.
Tatty
 

tatty500

Well Known and Active Website User
Non-VOC Member
But your initial post said:

"For one turn of the gearbox sprocket shaft the following turns of the clutch shaft(approximate)

Top 1.75

Third 1.33

Second 1.2

First 1.0"


So, the initial measurements must have the gears in reverse order.
Tatty
 

vibrac

Well Known and Active Website User
VOC Member
But your initial post said:

"For one turn of the gearbox sprocket shaft the following turns of the clutch shaft(approximate)

Top 1.75

Third 1.33

Second 1.2

First 1.0"


So, the initial measurements must have the gears in reverse order.
Tatty
Thats right
 

Howard

Well Known and Active Website User
VOC Member
Tim, I'm not sure what box the Comet Special and TT Rep used, but Richardson shows the ratios as 1:1, 1:1.16, 1:1.45 and 1:1.82 - close(ish) to what you've measured. ie Top 1:1 third 1:1.3 second 1: 1.4 bottom 1:1.75

H
 

vibrac

Well Known and Active Website User
VOC Member
bottoms.jpg
Here are the bottom gear set that was in my box No3 (top) and the 'standard' bottom gear set I have taken from my Albion gear cache (bottom)
As I suspected i8/30 is the nearest I can do against a 19/29 of the No5 box generally used on the original Grey Flash. I think that one tooth will not matter too much. A point to note with these boxes is that the smaller gear is often (for example on the standard set) the same tooth count as on the mainshaft top gear and at first glance they look identical but only one gear has a slightly raised edge (visible in the top small gear) this can be used on either shaft but one with a raised edge must be used on the layshaft (pointing away from the sprocket end).Why did Albion not produce both the gears with the raised edge you may well ask..yes indeed,why not? thats why I call them perfidious:)
I will now assemble the box, workout the overall ratios and this time sort out a chart of speeds in the gears against rear sprocket sizes
 

vibrac

Well Known and Active Website User
VOC Member
It is a good measure that I have too many bikes when I finally get to looking at the clutch failure on my Flash that occured at the flywheel meeting last summer
Its not the quick job I first thought. The 'top hat' adjuster on the RH side under the operating lever was difficult to remove and I found some friction welded 'thing' on the screw end (perhaps it was an unhardened adjusting screw?) the push rod is immovable in the shaft it does not look to mushroomed but it will not move a good poke from the clutch side will not move the rod either.
Thats enough scrabbling about on the floor I will get it up on the bench when I get the new rear units for the Egli Comet that hangs suspended there after suspension calculations.
Does anyone know the diameter of the clutch push rod? I have a dim recollection of 1/4" even dimmer is if it was in two parts with a ball or roller between.
ADDED content : the top hat contained a reasonable screw and the funny thing was a ball bearing welded to a push rod end so the trouble must be upstream the clutch end looks fine somethings jammed the rod in the shaft....26786
 
Last edited:

Black Flash

Well Known and Active Website User
VOC Member
Hello vibrac,
I have replaced standard shafts with longer commando shafts on two norton boxes to suit usage in a comet. The shafts were centre drilled from both ends and the holes did not meat head on. 1/4 pushrods always had too much friction for my liking.
On fleebay I could buy 6 mm silver steel rods at a very good price, cut to size clean the ends, heat with a blow torch and quench.
With this little extra clearance of 15 thou or so the clutch action was vastly improved. I have yet to see a mushroomed silver steel rod.
Just a hint while you are at rebuilding your box.
Bernd
 

vibrac

Well Known and Active Website User
VOC Member
That was my thoughts for once I shall go metrico_O. of course first I have the task of extracting the rod when I get my bench back I shall try from the clutch side after cleaning up the end. I once manage to drill down the entire length of a 1/4" broken rear wheel adjusting screw without hurting the thread in the casting I dont think I would get away with the length of a mainshaft:eek:
Silver steel - I just ask Mallard metals for a length :D
 

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