Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board BSA A65 4th gear mainshaft bushes

Trying to get a bike together and noticed that the bush from the 4th gear only stick out about 5 mm. As far as I understand it should be 31/64"(12,3 mm). Do I have to take both bushes out an then put them back in again or..? If so, how to do it and what to use. My workshop is not the best equipped..
Thanks!
Rgrds,
Lars

If you have x2 bushes, you will have to remove them both

We sell new units

https://www.classicbritishspares.co...ings?_pos=9&_sid=0a04c05ed&_ss=r

the original split bushes can be found here
https://degroot-bsa.nl/nl/product/bussen-hoofdas-a65-64-72-2-nl/

I've bought a set and now in the proces of replacing the bushes.
first objective: to get the old ones out

regards Anne

It may be more than your shop capabilities but you can make a split tool to drop in to the space between the bushes then expand it out with a bar between them, you can press the one bush without disturbing the other.
One way is a thick washer just smaller then the I.D. of the bush, cut in half. Drill and tap the end of a bar for a screw that will spread the two halves into the space between the bushes. Put the bar in the high gear with the end between the bushes, put the two halves in with another washer on top and the screw to hold them on the bar. Then you can press the one bush.

@Dmadigan I have made some of the tools you have mentioned on the lathe for driving out bearing races for various applications and they work great. Worth the effort if you're going to do it more than once. Plus, I like making tools and have a drawer in my shop of all the ones I've made over the years. Kind of a diary of my progression ;-0

Another method I've used for bushing removal has been to find an old tap of the appropriate size, start it into the bush until it's well bound, then drive it out from the other end with a drift that is smaller than the bushing I.D. I wouldn't buy a new tap for this purpose as it's not cost effective and definitely qualifies as abuse. But if you can one you don't care about that and want to dedicated to the task, it works great.

Jason

Thanks for your replies. I was not quite right about that the bush was 5 mm out. It is more like 2-3 mm which means there is no space between the bushes. I got a socket which is 23 mm and nearly exact the same as the outside diameter of the bushes inside the gear. I heated the gear a bit and tried to push the bushes out in a vice. I needed a tube which was +41 mm in diameter from the other side. The only tube I could find was an old seal holder from a front fork and that was to weak. I will try to find another tube which is stronger and try again.
BR
Lars

Another option is to push the bush completely inside and fit an outrigger bearing either from PES or Ed V.

When the bushes are pushed together they are not visible externally, and you need that for the outrigger to work.

I cannot comment about the bushes CBS sell (and I hope I am not doing them an injustice) but I have found when I have fitted new (split) bushes, they need reaming to fit the mainshaft. Cost of a decent expandable reamer won't be much different from the out-rigger plate and you would be giving more support on the main shaft. Some will comment that you shouldn't ream a split bush but I would like to know how they hone them to size?

Looking at the CBS site, theirs are not split bushes.

Another idea just occurred to me . . .

Since the bushes are pushed together with no gap in the middle there no way to gain purchase on just one of them to remove and reinstall.

Press both of them out as one from same side then reinstall them one at a time from either end. This assumes the gear is out of of the bike (is it?)

Jason

Or, you could push the bush in and replace the door seal with a National 474253 seal - 1.503" x 0.812" x 0.25". The only drawback is that gear oil that goes between the bush and shaft will leak out rather than into the primary, but the early engines had a felt ring to catch the oil and keep dirt out.

Yes, the gear is out of the bike. I will first try to find a solid pipe(inside diameter at +41 mm) and try to get the bushes out in my vice. Will heating up the gear give any help?
BR
Lars

Heat should not be needed, the vice should suffice.