10. BSA A10 Headline News

Time for some more A10 engine rebuilding including the cylinder head, oil pump and magneto.

It was time to rebuild the cylinder head. Upon inspection the valves and their seats appeared in very good condition and it was becoming obvious that this Super Rocket had had some attention to the top end more recently in its history. There was a marked difference between the top of the engine and anything that was inside the crankcase. So it was just a case of lapping the valves into their seats and, using a valve spring compressor, refitting the double valve springs, collets and caps.

That done, The head could now be offered up to the top of the cylinder block with a new head gasket and 9 new cylinder head bolts. The head tightened down beautifully using a criss-cross order for tightening the bolts to the correct torque. By the way neither the Haynes manual or the BSA service sheets tell you the correct torque setting for the head bolts. But a visit to the SRM web site lists them as 32 ft lbs.

It seems to happen over and over again, when building a classic bike, that just when you think you've made real progress something goes wrong. It happened this time, when I decided to drop the four push rods into place. The idea was to just rotate the crankshaft and feel them going up and down. The two inlet rods moved up and down beautifully, but the two inner (and longer) exhaust rods moved up and then stuck and it needed a tap with a soft faced hammer to make the cam followers drop back down onto the camshaft. There was no choice, the head and the barrel had got to come off again.

After stripping the head off and getting the cylinder block back on the bench it was revealed that the peg that fits between the two exhaust cam followers was not quite seated properly and had trapped the followers slightly twisted in their guides. I took much more care this time to ensure that the cam followers moved easily before clamping the peg in place with the small ball bearing and grub screw. Then it was out with the piston ring clamps again and rebuild the engine again. In with the push rods and this time they moved easily.

Time to set up the valve timing. This is quite easy. The cog on the crank shaft has a small dot punched on one of its teeth. The gear on the end of the camshaft has a line punched on the side of one tooth. The gear in the centre that meshes with the two has both a dot and a line punched on it. It's just a case of lining up the two dots and two lines and the valve timing is done! Easy!!

Time to look at the oil pump. It has been my intention that to make this bike look like a Rocket Gold Star, it must have both a speedo and a tachometer. Upon inspection I found that, whilst my Super Rocket had never had a tacho fitted, the casing did have the tacho drive mounting point. Lucky! Most A10 engines don't have them. The tacho drive is taken off the end of the oil pump shaft where there should be two small tongues that mate with the drive pin. My oil pump shaft had one tongue broken off. After a fair bit of searching around, I found a new oil pump shaft at SRM engineering. It fitted, but I then discovered that I should have fitted the oil pump before fitting the worm gear on the end of the crankshaft. Reluctant to disassemble the crankshaft gearing again, I decided to remove two of the oil pump fixing studs and rotate the pump up on the remaining stud until it meshed with the worm gear and then replace the studs. That worked.

According to the BSA service sheets, the magneto should be fitted next. After spending some time on the buffing wheel, the magneto cleaned up beautifully and fitted to the engine with nice new stainless steel nuts and the special long nut, that fits under it.Don't make the mistake of using an ordinary nut under the magneto. You might get it on while the bike is stripped down, but you will never get at it again once the bike is rebuilt. Magneto in place, things are really begining to look good!

 I would love to read your comments on this blog. If you would like to make some please click "Subscribe to: Post Comments (Atom)" at the bottom of this page. If you would like to be automatically informed when a new episode is posted then please tick the "Join this site" box at the bottom of the page. Thanks for reading. Kevin


 Copyright K. Hopcroft 19.08.12 All rights reserved
 You can contact me on: hopcroftscoot@gmail.com

My Other Blogs:

1961 Ariel Arrow Super Sport Motorcycle :
http://60sclassicmotorbikes.blogspot.co.uk/2014/01/1961-aerial-golden-arrow-restoration.html

Miniature Land Rover Defender:
http://miniaturelandrover.blogspot.co.uk/2016/02/1-miniature-land-rover-defender-idea.html?view=timeslide

1971 VW Karman Ghia Convertible Car:
http://karmannghiarestoration.blogspot.co.uk/2017/03/1-karmann-ghia-retoration-project.html

Motorcycle Trailers / Caravans:
http://motorcycletrailersandcaravans.blogspot.co.uk/2018/01/1-motorcycle-trailers-problem.html

9. BSA A10 Begin the Big End

It's time to start rebuilding the BSA A10 engine!. Having spent hours and hours on the buffing wheel, on the two crankcase halves and having obtained all new bearings, cam shaft, cam followers and oil seals, I started by assembling the crankshaft. The new big end bearings that had arrived were too small and turned out to be for the "small journal" type crankshaft. I returned them and received the correct ones and they fit the re-ground crank perfectly. The big end nuts were the next problem. The ones that I removed were the "self locking" type, but were so short that they lost half of their height into the recess on the con-rods, making them impossible to get a socket on them. I bought new nuts which had raised collars on them which lifted the hexagon high enough to torque them up properly. I then centre punched the threads above the nuts to prevent them coming loose.

I then pressed the new timing side bearing into the crankcase by heating the case and freezing the bearing and then pressing them together. Once fitted the bearing had pinched a little and it needed a final hone before the crankshaft would turn in it easily.

This done, the crankshaft was offered into the crank case and the second half of the crankcase was fitted. It was then possible to measure the crankshaft end float with a dial gauge. It turned out that the replacement crankshaft had less end float than the original and so needed one less of the shims fitting than the original.

The case could now be split again and the cam shaft fitted and then the two halves were given a liberal coating of blue sealant and then clamped together. The engine would now fit in the engine stand that I had bought, so that I could work on it in an upright position. The original pistons were re-fitted (which were in excellent condition) and then the barrel was next. Or so I thought. Sliding a barrel over one piston while squeezing the rings in carefully is difficult. Doing it with two barrels at the same time is impossible. So I decided to make some ring compressors. Two strips of thin aluminium wide enough to cover all three rings were bent around the pistons leaving two right-angle tabs where they came together. These tabs were drilled and fitted with nuts and bolts to do the squeezing. I slipped them over the pistons and tightened the bolts just enough to squeeze the rings without gripping them tightly and then rested the barrels on top of the clamps and pressed down gently. It worked a treat and the barrels slipped over the rings and into place. I was basking in my success when I realised that I had not fitted the cam followers inside the barrels before fitting it and so had to take them off again and the repeat the procedure.

Now with the crankcase together and the pistons and barrels in place, the engine was getting quite heavy and I felt that this was a good point at which to offer it into the frame. But how to do it without scratching my new, and still quite soft, paintwork. I came up with a plan!.

Having fitted the new chromed front engine mountings, I placed a piece of thick felt on the bottom  frame tubes and a piece of plywood on top of that. I then rested the engine on the plywood and tilted it until the top front engine mounting bolt lined up with the frame. In it went and I now had a pivot. I could lift the back of the engine, pivoted on the bolt and remove the wood and felt and then lower it until the second front mounting bolt went into place. It was in!!


I then added one of the newly chromed rear engine mountings on the left side and the Super Rocket engine was secure.

I would love to read your comments on this blog. If you would like to make some please click "Subscribe to: Post Comments (Atom)" at the bottom of this page. If you would like to be automatically informed when a new episode is posted then please tick the "Join this site" box at the bottom of the page. Thanks for reading. Kevin


 Copyright K. Hopcroft 18.08.12 All rights reserved
 You can contact me on: hopcroftscoot@gmail.com

My Other Blogs:

1961 Ariel Arrow Super Sport Motorcycle :
http://60sclassicmotorbikes.blogspot.co.uk/2014/01/1961-aerial-golden-arrow-restoration.html

Miniature Land Rover Defender:
http://miniaturelandrover.blogspot.co.uk/2016/02/1-miniature-land-rover-defender-idea.html?view=timeslide

1971 VW Karman Ghia Convertible Car:
http://karmannghiarestoration.blogspot.co.uk/2017/03/1-karmann-ghia-retoration-project.html

Motorcycle Trailers / Caravans:
http://motorcycletrailersandcaravans.blogspot.co.uk/2018/01/1-motorcycle-trailers-problem.html

8. BSA A10 Mud Glorious Mud (guards)

Let's just give a proper mention to my main parts supplier for the BSA A10 Rocket Gold Star replica that I am building. If you are attempting a BSA rebuild I cannot praise high enough this company. Take a look at their web site:  http://www.lightning-spares.co.uk of 170 Cross Street, Sale, Cheshire M33 7AQ. The owner Brian Pollitt is the most knowledgeable and helpful person that I have met when it comes to BSA's and if you are buying your parts from him, he is more than willing to offer advice and technical know how. I have found him so helpful, that I decided to buy all my parts from him (even if they are not the cheapest) in return for the invaluable help that he has given.

Having got the A10 sitting on its own wheels, I decided that it was time to take a look at the mudguards. Having decided not to put the original heavy black super Rocket mudguards back on, I bought a pair of lightweight stainless steel mudguards. The front one looked the easiest to attempt first so having bought a set a chrome stays (no stainless ones available), I offered the front mudguard in place. Unlike the original mudguards, these can be fitted with the wheel in place. The mudguard slid between the forks easily and the two back stays fitted no problem. However the centre and front stays were a different matter. A Gold Star has two lugs, front and back of the bottom of the fork to fasten the front and back stays to. My Super Rocket only has a back lug. Also the Gold Star has a plate sticking off the back of the forks, half way up, with two studs on it, to fasten the centre stay to. My Super Rocket doesn't. Instead it has two studs on the inside of the fork leg itself.

After some time designing and making cardboard templates I decided to make some thick aluminium mounting brackets to replace the missing ones. Because I could see exactly where the front lug needed to be (opposite the back one), I decided to make the front lugs first. Taking some 3mm aluminium plate, I scribed out an "L" shaped bracket and guillotined it into shape. I then bent right angles (one left and one right) into it to form the lug and drilled two mounting holes in it to fit the two bolts holding the axle end cap in place. I bolted the plate in place and then fitted the front stay and tilted it toward the new plate until it was in the right position so that I could mark through it onto the bracket for the lug fixing hole. Once this was done The bracket was removed again and polished before final fixing. Once finally fixed in place, it was obvious that I had made the lug a little too long (see picture) and so I removed it again and shortened it so that the two stay fixing bolts were the same distance from the forks.

I mistakenly thought that my design for the two centre plates would be much easier. After all it was just a flat plate. But my original plan of making a flat square plate with four holes in it turned out to be much more difficult than I thought. The plate needs to have its horizontal edges parallel to the floor to make it look right and the forks are at an angle. Which makes the holes at an angle. I made 5 cardboard templates and two thin aluminium ones before it fit. I then made the proper 3mm ones and bolted them in place. The stays fit perfectly but the plate looked horrible. So, using the first plate as a template I made two more this time with sloping sides to match the angle of the forks. Polished ad fitted, they now look great and the front mudguard is firmly held in place.

Now for the back mudguard. No fixing lugs on the mudguard itself. So support brackets had to be ordered so that I could see where the mudguard is supposed to fit. And it didn't! After have a long conversation with the oracle at Lighting Spares, it turns out that you have to cut the mudguard to length at the front to make it fit the frame. Having offered the mounting brackets into place, it was obvious that they did not fit the mudguard properly or the front of the two mounting points near the top of the rear shock absorbers (on the hockey sticks). So I decided to have custom stainless brackets made (aluminium would not be strong enough). and that is where I am at the moment. At this date the custom brackets have not arrived yet and so the rear mudguard is still awaiting fitting.

On the next blog, the engine rebuild begins.

I would love to read your comments on this blog. If you would like to make some please click "Subscribe to: Post Comments (Atom)" at the bottom of this page. If you would like to be automatically informed when a new episode is posted then please tick the "Join this site" box at the bottom of the page. Thanks for reading. Kevin


 Copyright K. Hopcroft 10.08.12 All rights reserved
 You can contact me on: hopcroftscoot@gmail.com

My Other Blogs:

1961 Ariel Arrow Super Sport Motorcycle :
http://60sclassicmotorbikes.blogspot.co.uk/2014/01/1961-aerial-golden-arrow-restoration.html

Miniature Land Rover Defender:
http://miniaturelandrover.blogspot.co.uk/2016/02/1-miniature-land-rover-defender-idea.html?view=timeslide

1971 VW Karman Ghia Convertible Car:
http://karmannghiarestoration.blogspot.co.uk/2017/03/1-karmann-ghia-retoration-project.html

Motorcycle Trailers / Caravans:
http://motorcycletrailersandcaravans.blogspot.co.uk/2018/01/1-motorcycle-trailers-problem.html

7. BSA A10 Wheel Meet Again

Leading up to this point, I had sent several parts up to my favourite chroming company, "Quality Chrome" in Hull, and after 6 weeks they had finally come back beautiful. These included the engine mountings and the front fork shrouds and also the rear sprocket

Earlier in this BSA A10 saga I had mentioned the rebuilding of the wheels, however there were a couple of things that I forgot to include. During the rebuilding of the hubs, all new bearings were fitted along with new oil seals and the hubs were cleaned and packed with fresh grease.

Fitting the new front left side hub cap turned out to be more of a challenge. The old hub cap was beyond rescue, as it was hand painted, rusty and dented. I found a new replacement (British Made) chrome plated hub cap on eBay and was very pleased with the quality when it arrived. However fitting it was a different matter. It should press over the left side of the hub and on the inside of the outer edge are three small pips that need forcing over the outer rim of the hub to hold it in place. No matter how I tried I could not press this hub cap on. I even turned a wooden mandrel to press down on the centre and the edge at the same time, but pressing on it just made the dome of the hub cap flex. I tried some gentle knocks on the mandrel with a lump hammer, but it just sprang back each time and I was becoming afraid that I was going to damage the new hub cap. What I needed was continuous pressure on the centre and around the edge at the same time. I needed a press.

So I took the wheel and hub cap back to my friend who has a hydraulic press, but the wheel (now assembled) was too large to fit in it between its two side pillars. True to form, he came up with an idea. He also had a large milling machine in his workshop. By placing the wheel on the bed of the machine and using the milling head vertical adjustment as a press we managed to slowly push the cap into place until the three pips went over the hub rim with a resounding "click". Beautiful, the hub was on and no damage.

Fitting the front wheel to the frame came next. I had noticed , when stripping the A10, that the bolts holding the front axle cups in place were of different lengths and spanner sizes. Upon inspection it was found that two of the threads in the front forks were damaged and shorter metric bolts had been forced in. I needed to tap out the threads in the forks and replace the bolts with the correct stainless new ones. Finding a tap to fit was a different problem. It turned out to be a British Cycle Thread 26 tpi and guess who had one? The man with the press and the milling machine. Once tapped out the wheel was offered into place and the brake plate located onto its lug to stop it turning when you brake. The two, newly painted, cups were then clamped on with the new bolts and " hey presto" the bike was fitted with its front wheel.


The back wheel next. The back wheel set up is actually in two parts, First you must fit the rear axle tensioner adjusters into the ends of the swinging arms. These are used to hold the axle at the correct distance to keep the chain at the right tension and stop the chain pulling the back wheel into the frame. Then the left side of the hub can be bolted to the left swinging arm complete with new bearings and seals and the newly chromed rear sprocket. The wheel is then offered in place between the swinging arms and finally the right side of the axle passes through the right swing arm and the wheel and screws into the left stub axle . This is actually quite clever as it allows you to remove the rear wheel without removing the chain.

At last, my Rocket Gold Star replica was standing on its own wheels!

I would love to read your comments on this blog. If you would like to make some please click "Subscribe to: Post Comments (Atom)" at the bottom of this page. If you would like to be automatically informed when a new episode is posted then please tick the "Join this site" box at the bottom of the page. Thanks for reading. Kevin

 Copyright K. Hopcroft 03.08.12 All rights reserved
 You can contact me on: hopcroftscoot@gmail.com

My Other Blogs:

1961 Ariel Arrow Super Sport Motorcycle :
http://60sclassicmotorbikes.blogspot.co.uk/2014/01/1961-aerial-golden-arrow-restoration.html

Miniature Land Rover Defender:
http://miniaturelandrover.blogspot.co.uk/2016/02/1-miniature-land-rover-defender-idea.html?view=timeslide

1971 VW Karman Ghia Convertible Car:
http://karmannghiarestoration.blogspot.co.uk/2017/03/1-karmann-ghia-retoration-project.html

Motorcycle Trailers / Caravans:
http://motorcycletrailersandcaravans.blogspot.co.uk/2018/01/1-motorcycle-trailers-problem.html

6. BSA A10 Stand up and be counted

It's funny, but you don't tend to think of these things in advance. Having fitted the front and rear suspension. The next stage was to fit the wheels. It then occurred to me that the bike would not stand up, once the wheels were fitted. So I had to turn my attention to the centre stand.

The centre stand was not in good condition. Someone had welded a bent bolt to the side of it, to provide the foot pedal and the pivot holes in it were worn large and oval. Equally the pivot holes in the frame were also worn and oval. I have previously, during stripping, decided not to have the stand painted as it would require some welding and cosmetic repairs to bring it up to standard, before it could receive it's black paint.

Now in order to keep the A10 upright, it needed to be fitted. I obtained a piece of brass bar and set about turning two new brass bushes, on my lathe, for the stand and two for the frame. The holes in the stand and frame were drilled out to a larger size and the bushes made slightly oversize so that they were a press fit. A new stainless steel pivot kit was purchased and the centre spacer tube had to be shortened  in order to accommodate the thickness of the bushes.
Finally the new chrome stand spring was fitted and the stand was ready for use.

The holding split pin in the pivot rod has not been bent over, as sooner or later the stand must be removed again to have the welding done and the paint applied. But that is some time in the future. Right now it's ready for some wheels!

I would love to read your comments on this blog. If you would like to make some please click "Subscribe to: Post Comments (Atom)" at the bottom of this page. If you would like to be automatically informed when a new episode is posted then please tick the "Join this site" box at the bottom of the page. Thanks for reading. Kevin


 Copyright K. Hopcroft 01.08.12 All rights reserved
 You can contact me on: hopcroftscoot@gmail.com

My Other Blogs:

1961 Ariel Arrow Super Sport Motorcycle :
http://60sclassicmotorbikes.blogspot.co.uk/2014/01/1961-aerial-golden-arrow-restoration.html

Miniature Land Rover Defender:
http://miniaturelandrover.blogspot.co.uk/2016/02/1-miniature-land-rover-defender-idea.html?view=timeslide

1971 VW Karman Ghia Convertible Car:
http://karmannghiarestoration.blogspot.co.uk/2017/03/1-karmann-ghia-retoration-project.html

Motorcycle Trailers / Caravans:
http://motorcycletrailersandcaravans.blogspot.co.uk/2018/01/1-motorcycle-trailers-problem.html