So I finally got the big end bearings sorted, sludge trap installed (and cleaned) and all the cases cleaned up and new gearbox bearing installed as the old one was too far gone.
I read a few people have made tools to fit the small end bearing, does anyone have any guidance on the best method for this? I tried the over and freezer trick but it seems the BSA parts are way more tighter than other bikes I have worked on.
Presume a tool is needed to fit the piston pins also as they are an equally tight fit? or do people get them press fitted at an engineering shop?
I saw the old BSA tool in the manual but havent seen any for sale.
Hi,
Here's some help if you haven't got a lathe to make a tool.
https://www.suspension.com/blog/how-to-install-a-bushing-without-a-press/
Best wishes...
I pull them in with a home made tool comprising a socket, some studding, nuts and washers. (as per above post)
You will need to ream them once fitted so the piston pins (gudgeon pins) are a sliding fit.
Tight pins can nip up on the gudgeon pin and rotate and the bush then the oil holes in the conrod and pin no longer align.
Its no fun when the small end gives way, although you do get some warning DAMHIK!
Amazing thanks for the help, I did think they would need some adjustment after fitting, looking at it now the fit would be far too tight and would probably push them out.
:) :) :) :)
I'll be quite honest I no longer mess with small end bearings. I take the conrods and a gudgeon pin to the nearest engineers and have done with it.
Can save a lot of agro.
Mike 8) 8) 8)
Something to be said for that Mike.
Its not easy to ream well by hand.
However I can't find an engineers these days that will turn things round in less than 2-3 months!
I used to worry about affording the work, as I get older I have to wonder whether I will still be able to ride by the time I get the pasrt back :(
:) :) :)
Yes I understand that point. Fortunately there are a couple local to me who are happy to do the odd job out of sequence. I accept there will be delays but!!!!!
Mike 8) 8) 8)
the main thing with reaming the small ends is to get them in square and reamed square with the right amount of clearance.
my advantage is that we do re fitting and reaming bushes for train brake compressor rebuilds, although not the same size, i can use the 2 ton press and have adjustable reamers and if needed a horizontal hone at hand.
Hi,
I use a knackered con rod with the small end bush removed, a long nut and bolt and a socket. Warming the small end does help a bit and the socket pushes the old bush out and in to the old rod. This all helps to keep things square. If you keep it lined up this can be done in vice if the rod is not in the bike so not using the bolt.
To fit the new one, replace the socket with a large thick washer. Heat the small end in hot water and the new bush will start to go in but be quick as the bush will take some of the heat and soon become tight. Tighten the bolt until the new bush is flush with the face of the small end. If the rod is not in the bike the vice can be used to push the new bush in but protect the face of the con rod.
I found a reamer that is exactly the right size and it has a reasonable lead in so not too difficult to use so long as it is kept square to the bush.
To fit the pins, pistons are heated in hot water so just about handleable and they just slide in. I always get them central so that there is no pressure on the cir-clips. I know in use the pin can move slightly but I feel it is best to start with an ideal position. Also, plenty of oil as you slide the pin through the bush. It is only splash fed in use so needs some for start up.
Dave.