Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board 71 b50ss lost ability to shift, help!

Yes, tap the camshaft back in or the cam followers will drop and you will also lose the cam timing, not that its difficult to redo just you want less to do not more. Hopefully the cam followers have not already dropped, check the rockers do not have excessive clearance.

CT.....you do understand that the camplate shoukd stay in place and the cover comes off of it. Same with the shifter and the main shaft....if the shifter and or the camplate moves with the cover when pulling it off...push them back too.


Sorry this seems to be such a pain....I've never done this with a B50 but I don't think we've left anything still attached....that puppy should come off.

Wish you were closer.....I'd be there in a heart beat....opie gone bad

The Shifter is the only item that will stay on the cover, as it comes off its pawls will drag over the camplate and some manipulation will be required, put the gearchange lever back on and that allows you to move waggle the shifter to get the pawls disengaged.

kommando, it's been way to long since I did this and I'm really at a loss at how it all sorted out....I just know I've done it twice by myself and helped a fellow once. I figure if I can do anybody can.

I'm thinking the shifter did indeed stay with the inner cover.....but what holds it in it? Isn't it just a sliding fit through the cover?

I figure you would want it on the inner cover when you reinstall it so you can be sure the spring is on the post...but would it hurt if the cover came off without it?

Opie Gone Bad

Okay, ill just update tonight and follow up with pics tomorrow. I got the cover off with a lot of prying back and forth with a wood block on the cam side and a lever on the other. It is indeed a broken camplate spring. Bad news is that i pulled the cam out with the cover. Good news is that maybe i can take care of that stripped gearshift shaft while im at all this? But, lots of questions tomorrow along with pictures....

Sorry it was such a pain. Getting the lifters, push rods and cam back in place isn't going to be hard at all (of course that's what I said about pulling the cover )

I would figure out WHAT made that cover so hard to pull off and fix that BEFORE it goes back on. If it was the bearing for the main shaft I'd take it out and dress it up to be sure it is a sliding fit.

The covers are a metal to metal fit so I'd check and clean up any damage your lever might have done to the mating surface.

If you'll send me your snail mail addy I probably can help you with a good used shifter shaft.

I won't get into what I do different from what BSA says about the spring....if somebody else brings it up, that 's a different story.

Kicking it in Mayberry......OPie Gone Bad

I'm waiting for the part to come in at my local mechanic and am thinking about the stripped drain plug on the primary side. He recommended that I get a self tapping drain plug but they're all like 1/2". Should I drill it out in place (if a drill would fit under there) so it's a closer hole to 1/2"? Or would tapping it be easier? Do you have to worry about shavings in the case?

The primary drain plug is threaded into the primary cover, which will come off easily. Whatever you decide to do, it will be better with the cover off. I would go for a thread insert (helicoil type) of the correct size, to restore the thread rather than tapping a larger, non-standard, thread. I'm sure someone here can tell you the thread of the drain plug. Using a thread insert will cost you a little more than just tapping a larger thread, but it's not difficult. And you can keep the old plug.

Well the part is in so ill be picking it up later today ($9). Not sure that ill be getting to it anytime soon but will post pics when I do. Gordon, I think your idea is a good one to take the bearing out and make sure it's a sliding fit on the main shaft. Ill pick up a retaining ring remover from Harbor freight later today.

Couple questions for you guys:

1) When the case came off and I was taking inventory, there was a 1/4" steel ball on the floor. Only place I can imagine it came from is there's a recess behind the shift lever that would cradle it...and all the balls were present in the mainshaft bearing so its not that.

2) Can anyone instruct as to how to insert the cam? Would the lobes go up or down? Is there a diagram? I know the lifters (if that's what they are) that fell out when the camshaft came out look like they should go in a certain way.

3) What is needed as gasket material between the cases? There is red residue on the sealing edges, I assume I should clean all that off.

4) Is there a certain position that the camplate needs to be in, a certain gear or something, as I attempt to put this all back together?

Thanks so much for all your help...

Hmmm, Folks have been incredibly patient in this thread. Most of your questions have easily accessible answers in either the Rupert Ratio book or BSA service manuals for this bike. This whole process would be going much faster and clearer if you had these on hand to look at. The steel ball is likely 7/32 and goes in the end of the clutch pushrod actuating rack. Held in place by a blob of grease. With the cam you need to align it with the timing pinion gear. Look for the lines or dots. It makes difference what way you reinsert the cam followers. That's also in the books. It is a real good idea to lube the cam and followers with assembly oil. It is special stuff! Old gasket goo not only needs to be cleaned off but the case edges should be wiped down with degreaser so they have no oily residue when you apply a thin layer of new goo. I like the red Permatex anaerobic sealant. The gears and cam plate all need to be inserted together. Position in neutral! The diagrams on where neutral is and how to do it all is in the manual and in Rupert Ratio. It has been nearly 20 days since I wondered in this thread if you have any of this literature on hand. I hope I am not being too subtle on this final point.

Good luck Peter

Hi Peter, I have this manual. http://thumbs2.ebaystatic.com/d/l225/m/mgb1jwTEEIEqf8L2xR3eUwg.jpg

Yes I appreciate the patience of the group here, being a novice bike mechanic I find it helpful to get these explanations in terms I can understand and cross reference them with the manual. It's the only reason I've gotten this far (which at this point is no further than my last post- mainly because I rode my Honda into the cold weather and haven't been back out in the garage until the other day).

But I am attempting to still put it back together, but have listed it for sale as well. Both on craigslist and the for sale area of this forum.

http://newhaven.craigslist.org/mcy/4337751401.html

OH my.......what a DEAL!!!! If I had the extra money I'd take it off your hands today.

I can't imagine that bike for that price taking long to sell...if I thought it'd take a month....I'd start saving now.

I'm heart broken..... .....Gordon in NC (aka Opie)