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Pre War / Re: 1932 Blue star HELP!
« on: 25 November, 2017, 11:07:49 »
Been on my back under the Blue Star this morning - freezing it was too! 1. This is as you say crankcase width which is on mine 4 1/8 inch. 2. Difficult to achieve an accurate figure without removing the rear wheel, but you will be very close at 6 1/8 inch. 3. Also governed by the crankcase rear through bolt, but the bosses for the brake rod (a couple of inches to the rear of that bolt), are 4 1/4 inches apart. Personally I would base measurements for 1 and 3, by fitting the bare engine crankcase in place. I have used fractional imperial units as I believe that is what would have been used at the time. Hope this helps. PM me if you need further details.  Malcolm.

Pre War / Re: 1932 Blue star HELP!
« on: 24 November, 2017, 17:17:10 »
My 32 Blue Star has, what I would call a "square" sump with rounded corners to the front, with the filler cap to the right. Brake pedal is on left with crossover to front and rear brakes (dual braking off pedal). Right hand handlebar lever operates front brake only.

Pre War / Re: 1932 Blue star HELP!
« on: 24 November, 2017, 11:05:49 »
Hi Fred, I have a very original 32 Blue Star which is a 500, but I am sure all other details will be the same. Let me know what measurements you require. I am in North Yorkshire.

Twins / Re: Torque settings again.
« on: 12 November, 2017, 21:40:35 »
Thanks to you both - I will have a celebratory drink ;D

Twins / Torque settings again.
« on: 11 November, 2017, 14:15:12 »
I have recently rebuilt the 1952 A7 engine and tightened the big end caps on the alloy connecting rods using data from the BSA SERVICE SHEET No.208. My rods use the later 26 t.p.i. bolts and the  recommended torque setting for those in the service sheet is 8.5 lbs.ft. Sometime afterwards I was reading the D. W. Munro book on BSA Twins and in this he quotes 22lbs.ft. for all the models. I borrowed a very hi tech torque wrench for the job as my own was off the scale at such a low setting. I am having sleepless nights about using the lower figure - any words of comfort out there.

I personally do not understand the DVLA`s point. How else could my machine physically bear the number plates as one of the four allocated registrations reserved by the dealer at the same time BSA factory records show it despatched to the very same dealer - I cannot imagine any scenario to achieve that. At some stage they will have to issue a registration for the machine, age related, Q, or even if I could prove a link to the chassis number, it would still be non - transferrable. So if I can show a good connection to the machine for that number - which I believe I can, what does it matter if they issue that number, because no one can actually make a monetary gain, but importantly to those of us interested in old motorbikes, the history of the machine stays in tact, despite the fact that the machine has not been used for years. The bike will need a number so it might as well be its original one!

Coming to the end of a restoration of an A7, which came to me dismantled, no papers but still fitted with the front and rear number plates. One of my first jobs was to get an "information only" dating certificate from our man Steve Foden. this fortunately showed it to have its original engine, so obtaining an age related number should not pose a problem. This certificate also detailed the original m/c dealer who sold the machine with date. I also got in touch with the Kithead Trust who hold many of the registration number records. They matched the registration on the machine and supplied evidence to show, that the dealer on the dating certificate, had reserved 4 sequential registration numbers, which include mine, on the appropriate date for his business. However because there is no reference to a frame number, I will still not be able to reclaim the original number!

I am not bothered about it being transferable, but I feel it is sad that in such a case, that the DVLA has to be so rigid. Much of this has been brought about by abuse of transferable registrations over the years. Once sorted and if available, I might try and buy the number to put it on the machine, just to set the record straight.

Twins / Re: Plunger A7 clutch
« on: 19 June, 2017, 11:50:15 »
Since my last post, I have come across several used pressure plates and all barring one were dead flat, which is what we would expect. The odd one was dished exactly like my original two. I bought one of the flat ones and is now installed.

I drilled the six spotwelds through on one of the old ones to separate the two pieces and it is easy to see that the dishing of the flat plate occurred during the spot welding process during manufacture as the outer piece is not a dead flat surface, probably due to not being pressed to shape enough. The dished ones have probably given thousands of miles of service, once bedded to the outer friction plate.

One of the dished ones is not wasted - cut out the centre to allow for a socket and welded a bar to it, to lock the clutch centre when tightening the nut.

Twins / Re: Plunger A7 clutch
« on: 29 May, 2017, 22:05:52 »
Hi, Thank you for the advice, but I too have an A10 special with a 4-spring clutch which is good, but equally I currently have a B31 and have owned both another A10 and B33 that had the 6 spring clutch fitted. The later 6 spring clutch when set up correctly and fitted with parts that are not worn out or damaged, can be a perfectly good clutch too. It is my intention to do the same with my plunger A7, which to me looks a better design than the later clutch fitted to the S/A models which is the one I feel you are referring to, but I accept that experience may change my view on that.  I am also not sure that the 4 spring clutch can be made to fit the plunger models anyway.

This is why I need to find out whether the dished plate is a design feature or not, for interest if nothing else. If it is not correct I will buy new.

I also would also like views on the experience of others, what Surflex plates are like in a "dry" environment, as such inside the sealed clutch of plunger models.

Twins / Plunger A7 clutch
« on: 28 May, 2017, 21:44:22 »
On rebuilding my 1952 A7 clutch, I notice that if I put a straight edge across the friction surface of the outer pressure plate (67-3245), there is a pronounced "dish" ie it is not flat. The "dishing" is uniform across all diameters.  The difference is about 1mm at the inner diameter of the friction surface. I would not expect this, but on looking at a spare clutch that I have, it is exactly the same? Both correct or both wrong? All other plates are dead flat. Don`t want to buy new if that is how they are.

The outer plate is made up of a pressed spring plate, spot welded to what looks like a standard plain driven plate. Does the spot welding create this "dishing"? How/why would it need to be dished. Could easily be overlooked.

Whilst on the subject I am contemplating using "Surflex type friction plates, which in many applications are wet with oil, but not so in this type of BSA clutch if properly sealed. Do we still use the cover?   Appreciate informed thoughts on this.  Thanks.

Singles / Re: M33 1955 - Starting Issues
« on: 24 April, 2017, 21:45:10 »
With the bike on the centre stand, remove the sparking plug, put the bike into 2nd or 3rd, push on the rear tyre in the road direction and when you look at the contact breaker rotor, it will be turning clockwise. Operate the advance retard lever and check what you have to do to move the cam ring in the opposite (anti clockwise) direction. That will be the way to move the lever to full advance - opposite direction to achieve full retard. So now you will know whether you have a "tight" or "slack" cable advance. The other way to check is to look at the contact breaker and if the adv/ret cable is on the right of the CB, then it is a tight cable advance - on the left a slack cable advance. It would be nice if all were the same, but over the years swaps take place, incorrectly as Julian mentions. Extremely important information to know about your bike, both for starting and running.

Now push slowly on the tyre again, with a finger over the plug hole  and when you feel compression you know the engine is with the piston rising towards TDC awaiting a spark. Lets check this is happening at the right time? Using a thin rod of some sort, one end resting on top of the piston, SLOWLY continue moving the rear wheel until you reach the highest point the rod travels and mark the rod with some reference point to the outside of the engine. That is TDC. Once found carefully recheck and then with your adv/ret lever in the fully advanced position, turn the engine backwards a little to send the piston partway back down the bore. Once done, this time moving the engine slowly forwards again, mark the rod at the point the contact breaker JUST opens. Measure the gap between the two marks which should be in the order of 7/16 inch. If not the magneto needs re-timing correctly.

Twins / Re: Electronic ignition
« on: 16 April, 2017, 20:32:34 »
What is recommended for an A10 with the K2F magneto. I have always been happy with magnetos, but the one on my A10 is getting tired. I have a spare u/s magneto that I would be happy to convert to keep looks correct. The bike is already 12volt. Anybody have any experience doing that?

Singles / Re: M33 1955 - Starting Issues
« on: 03 April, 2017, 20:57:43 »
It is very easy when you have had these singles a long time and CAN start them, forget how b... difficult they can be when you first get one and need to master the art. So my reply is based upon the supposition that you may be new to this machine - apologies if not the case.
My method is set the advance/retard lever partially retarded, fuel tap on. While the carb is filling take the engine to compression and if one is fitted, use the de-compressor to ease the piston just over TDC. If bumping off, put the gearbox into second and pull the bike backwards until you meet compression resistance. Doing either of those will put the piston near the start of the power stroke and will, when set in motion allow 3 strokes or 1 1/2 revolutions before the piston meets compression again, when the kinetic energy stored in the flywheels will be enough to take it past TDC and hopefully fire and hopefully run. Now when that is done, I then give the carb a light "tickle", but not to the point of flooding. This raises the fuel level slightly above normal and will help the engine to "catch". With the throttle only slightly open give that kick, or bump start to set those flywheels in motion. All things being equal it should at least fire if not burst into life. Good luck!

« on: 29 March, 2017, 21:30:50 »
Thank you for your replies. What prompted my initial post is that I have a s/a A10 which is a bit of a special, fitted with WM2 rims and shod with 19X4.10 (100/90)  Avon Roadrunners front and rear. Although I have only done about 400 miles on these tyres, all seems to handle well with plenty of clearance where required, but having two tyres the same has come in for some banter! If the tyres are a bad fitment, I do have an economical way out, as I am coming to the end of a plunger A7 rebuild which is now needing tyres for its WM2 rims. Do I buy a pair of smaller profile tyres to use on the fronts of the two bikes and use the partially used Roadrunners on the rears?  What tyre pressures should I adopt?  Rightly or wrongly I usually put in 2 bar, just to ease the fading memory cells!  :-\ 

« on: 27 March, 2017, 21:29:02 »
Been having discussions/arguments recently regarding tyre fitments and pressures used on typical post war motorcycles and would welcome opinions from the forum. What is the point in having different tyres front and rear? A typical post war machine with 19 inch WM2 rims may often specify 3.00 front and say 3.50 rear. Why not have them both the same? Early A7 with Q/D hubs front and rear were intended to be interchanged. I can see that modern sports bikes need them different, but our relatively low powered classics - I am not so sure. Also early specification for tyre pressures, to me seem on the low side for modern tyre equivalents. Love to hear your views.

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