Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board 1957 BSA A10 GF engine problem...

Oh dear.. please enlighten this twin novice.
Have I done a novice error???
I had started to remove primary/clutch/gearbox on my 1957 BSA A10 GF.
In the middle of this I decided to put it together without removing the gearbox.
In the process I swapped to a 4-spring clutch I had on the shelf.

After tighten it all together except for the outer primary cover I decided to start it and test ride it with the used 4-spring clutch that only has 4 friction plates (for a smaller cc Triumph or a 350cc B31). The intention was to see if it takes the force from this 650cc.

This is now when the strange thing occurred suddenly I could not turn the engine around.
I thought it might be the clutch that could be to tight but after removing the cush drive and primary chain I noticed its the engine.
I can turn the engine either a bit forward or backward but it suddenly says "Clunk" and dead stops, I did try to move the bike when assembled back and fourth so obviasly I have put it under a good Manual force.

The engine ran without trouble before disambling as it was the gearbox that behaved a bit strange as i had difficult to put in neutral when I rode it.
OK when disambling I moved the engine crank shaft back and forward manually and also felt the end play which seems ok but I have not actually meassured it.
Doing that could I have gotten the pushrods to jump out off its position? is it bad to turn the crankshaft backwards???
somehow i feels like the camshaft is getting stuck HOWEVER I'm not sure.
It could be anything else but this is what I experience right now.

Please enlighten me if you can.
Thanks

The 2 bolts on the inside of inner primary that are safety wired together are they the right one? if to long they might be causing it. I have never had a problem turning backward when timing but if your valve adjustment was way off you might drop a rod.

Hi Morgan, Did you replace the 3 larger screws at the front of the inner primary case without replacing the outer case? If so, these screws go all the way through the crank case and will stop the flywheels from rotating. Just a thought !!!

Beezageezauk

There also should be a spacer with two fairly thick gaskets on either side behind the inner primary cover and engine case. If this was left off that would definitely make the bolts thread into the inside of the crankcase further and maybe fowling the crankshaft.



Bill B...

For some stupid reason i had screwed in the long three screws into the case and forget about them so they are now bent on the inside by the flywheel. Stupid me I have not worked on a a10 before. I need to sort this out soon maybe cut the heads and screw them in if possible they don't go out

Not sure this is a good fix. How do you retrieve the threaded part you've screwed in? As much as you may not want to hear it, I think you need to split the cases and remove them from the inside.


Bill B...

Hey Morgan,

At least you found out what the problem was but I agree with Boomer. You will probably need to split the crankcases and remove the damaged studs from the inside.

Beezageezauk.

Three possibilities come to mind. I don't have any experience with an A10 though, so I have no idea whether any would work.

1)If the screws are relatively small in diameter, you could try bumping the crankshaft backwards to bend the screws back and grab the heads with a pair of vice-grips so that you have more leverage for unscrewing. Probably won't work, Might strip the holes in the crankcase, but that is fixable and I don't think you have much to lose by trying it.
2)Rotate the crank so its in between the "stops." Cut off the heads of the screws. Using a dremel, cut a screwdriver slot in the remaining shank. Screw the shank in until it falls into the crankcase. Take the sump off, and using a magnet, fish out the screw shank.
3) Do the same as no.2, but instead of making a screwdriver slot, use a left hand drill bit to drill as much of the screw away as possible. With luck, and depending on how much the screw is bent, it may back out for you. If not, you should still be able to push the bent portion forward into the sump and fish it out with a magnet.

Ed from NJ

Oh dam!..sympathetic BroHug Morgan!

some good Bodges there Ed, I'm taking notes. :bigt

Look on the bright side of life Morgan , you KNOW you wanted to clean the sludge trap and have a 20 page repair thread about it all......

Well I rather fancied myself as a reasonable inorganic chemist having been a NATA certified analytical chemist for copper, aluminium & lead based alloys but this one has me miffed.
Tried it and it actually worked really well
Removing steel from alloy

Any of you better chemically endowed than I who can explain the chemistry of it I would be greatly appreciative.
I have a stubbon distain about doing things I don't understand ( SWMBO excluded )

'Focus you Faack!!!'

humor and technology, all in one, it's a hit.

So, Morgan, got any hi temp siliconey?

thanks Trevor, that is a cool Bodge fer sure.

The trick, Morgan, is not dissolving your flywheels at the same time...

Hi Morgan,

Theres room inside the crankcase for you to cut the screws on the threaded portion and screw them into the crankcase
You will need to rotate the crank so the web will be clear of the stud ends
Just before dead centre the top front screw should be clear
I have a photo of crankcase and crank but cannot get my photobucket ac to work (crapp!!)
Send me a pm with your email and I can send it directly to you

John

Oh dear...yes, I'm afraid the only solution is to split the cases. Wish I could come over and give you a hand....