Author Topic: BSA A10 Breather Replacement - Advise  (Read 751 times)

Offline ALPH1

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BSA A10 Breather Replacement - Advise
« on: 17.09. 2019 10:17 »
Hi All,

This is my first post and would really welcome some help advise Hopefully this is in the correct area

Ok summing up the issue Im having:

Bought the bike 59 Golden Flash, barrels and rocker covers were in pretty scruffy shape. Removed and vapor blasted and painted up, barrels just had paint removed, cleaned and painted. Reassembled with all new gaskets, fuel taps, fuel lines, plugs, tappet clearance set to 008, 010. hold that thought.. Bike started second kick but was blowing some black smoke (rich) maybe. Started to tune the carb and found some washers were leaking. New gaskets and tuned some more, dropping he needle 1 notches. Took it for a spin and noticed  loss of power at 3rd and 4th.. Dropped the needle another notch and much better.. Took it for a longer spin, driving OK but loss of power on hills and pretty bad oil leak of the rocker covers. More gaskets and sealer oil leak fixed but still had a loss of power in higher revs and on hills. On further reading I noticed the tappet clearance should have been .010 .016 so I set this and took off on the bike.. Seem like it had more power but then... disaster. Blowing a lot of white smoke and oil coming out of the breather pipe. Plugs were heavy fouled and some oil was coming from the pipes.  I stripped it down and a lot of oil was in the cylinders and the head gasket looked blown.. oil on it and the outside of it. while I was there I checked for wear on the piston rings +60. and with a calipers noticed some difference is the thickness and the gap was .030. OK time for a new set I thought. New head gasket and rings installed. Started up the bike and its running very lumpy. Tappets set back to 008 0010 (good for easy running so Im told) No white smoke or oil coming out of the pipes but plugs are sooty, (rich condition)? OK so major problem solved I think but I have not drove it so cant be 100% but this is still my issue. Its still blowing oil out of the breather pipe. So my next play was to check and replace the cork breather washer.. I took off the timing case half pound of grease fell out. removed the 4 inner screws but now Im stuck.. Do I need to remove the chain? or the 2 nuts holding the chain. if i tun the nuts the whole thing turns.. and when I do remove it when does the washer go.. PIC attached.. Thanks again for any advise or help.. Next stop is a mechanic but think I would feel defeated in not solving this.     
 

Online Greybeard

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Re: BSA A10 Breather Replacement - Advise
« Reply #1 on: 17.09. 2019 11:04 »
Hi and welcome. Your post should be in engines, (I expect one of the moderators will move it).

When you get a chance, will you go to Introductions and tell us something about yourself, roughly where in the world you are and any previous motorbike experience.

I'm sure you will soon get suggestions about your bikes symptoms.

Online muskrat

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Re: BSA A10 Breather Replacement - Advise
« Reply #2 on: 17.09. 2019 11:50 »
G'day Alph,  *welcome*
You will need to remove the larger sprocket. It's on a taper so may be difficult. Once off keep pressure on the shaft when removing the inner cover as to not upset the cam/ignition timing.
If you can't remove the sprocket you will need to loosen the dynamo strap and turn the dynamo anti clockwise to loosen the chain and remove it. Make sure the pistons are at TDC. Now the cover will come off but it will take the idler pinion with it. DO NOT turn the motor over (chance of bending a valve). Now you have a better chance of removing the sprocket by setting the cover on blocks and press the shaft through the sprocket (heat may/will be needed on the sprocket. Once it's off replace the idler pinion back in observing the dot to the crank pinion and dash to the cam pinion.
Now you can look at the cork. Should be thick enough to have 10-20 thou crush when the cover goes back on but triple check the timing marks are correct first.
Good luck.
Cheers
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Offline ALPH1

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Re: BSA A10 Breather Replacement - Advise
« Reply #3 on: 17.09. 2019 12:23 »
Hey Muskrat, Thanks for the reply.. I think Im now in more trouble because while trying to remove the nuts I did turn over the engine and had feared this would upset the timing. Something new I'll now have to try understand and deal with. Its like the rabbit hole this!
Larger sprocket? center nut in the pic I posted? I did get that off and it has a washer with folded over edges. I was still unable to remove it but it came forward a little. It did move some but not off. TDC required to get it out and should have been done before I removed the first cover?

THANKS!!

Offline ALPH1

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Re: BSA A10 Breather Replacement - Advise
« Reply #4 on: 17.09. 2019 12:59 »
And WOW just like that 2 minuets later the cover is off.

"it will take the idler pinion with it" The bolt in the center large sprocket? if so that seems to have stayed in place. If it did not come out do I need to be concerned  about dot to the crank pinion and dash to the cam pinion.

I can now see two washers left is the breather and right the dynamo. may a well replace both while Im here right.
Is that washer just sitting there. or do I need to remove anything before going at it. It looks in bad shape as you can see.

I feel a whole wave of fear leaving.... Thanks GUYS!!!!

Al

 

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Re: BSA A10 Breather Replacement - Advise
« Reply #5 on: 17.09. 2019 13:48 »
 *welcome*ALPHI1 put the breather in the cover put the cover on with a couple of screws nipped up and see if you can push or pull the breather in and out. the cork looks crushed ok just test for movement in and out and see if you get resistance trying to turn it clockwise and anticlock against the driving peg  ie easy to move or stiff . if these tests are ok leave that cork in

Offline ALPH1

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Re: BSA A10 Breather Replacement - Advise
« Reply #6 on: 17.09. 2019 14:05 »
Thanks Berger for the welcome and advise.

Just did that and indeed there is play in and out and some left right.. not so much left right but in out seems really loose. Its minus the gasket at the moment but this could not account for the play Im seeing. 10-20 tho crush, washer should crush by 10-20 and no play?

Thanks again.

AL

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Re: BSA A10 Breather Replacement - Advise
« Reply #7 on: 17.09. 2019 14:12 »
yes put the washer on and breather in case / fasten up with the three screws and try it , if it pulls in and out or you can rock it easily against the driving peg the washer needs replacing or another washer of thinner cork/ gasket making to take all the play out, if you look at the cork you will see where the breather has crushed it

Offline ALPH1

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Re: BSA A10 Breather Replacement - Advise
« Reply #8 on: 17.09. 2019 14:29 »
I should have been more clear here sorry. When I said without gasket  I was meaning the case gasket I did actual put back the cork one and had all that play in it. I have spares  of various sizes that came with the gasket set and I'll test for a good fit. Only concern I have now is what muskrat stated:

Trippe check the dot and dash. I can see these.. as in the pic. How do I know if these are correct and Im guessing I cant turn anything now with the cover off.

Guys I really didnt expect the level of help Im getting and so quickly. I hope to repay in kind once Ive enough knowledge myself..
Thanks!

AL


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Re: BSA A10 Breather Replacement - Advise
« Reply #9 on: 17.09. 2019 14:54 »
The left hand gear, (pinion) in your last photo is on the camshaft, controlling the valves. The crankshaft, (small pinion) obviously moves the pistons. As long as the pistons are not at top-dead-centre, (check through the spark plug hole) the camshaft can be safely rotated by putting a spanner on the nut and turning clockwise* to get the timing mark in the right place to line up with the idler pinion. Next, take the idler pinion out and get the crankshaft pinion in the right place. Put the idler back, making sure all the dots line up. You may have to rotate the camshaft a little as you do this becuase the pressure from the valve springs may have moved the camshaft lobes a tad. Take care not to force anything.

*As you will be causing the valve springs to compress and release, expect the movement to be grabby.

Offline ALPH1

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Re: BSA A10 Breather Replacement - Advise
« Reply #10 on: 17.09. 2019 15:29 »
Thanks Greybeard!

"As long as the pistons are not at top-dead-centre" they are as I put them at TDC to remove the cover. Does this upset the cart.

Thanks

Al

Offline RDfella

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Re: BSA A10 Breather Replacement - Advise
« Reply #11 on: 17.09. 2019 16:40 »
I am not clear here. Did the idler pionion come out when you removed the cover? If it didn't, then the timing should be OK and all you need to do is gently turn the engine so you can check the marks line up. If it did come off, then you have to start as Greybeard says.
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Offline ALPH1

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Re: BSA A10 Breather Replacement - Advise
« Reply #12 on: 17.09. 2019 16:41 »
Just so ive got this correct before I make and adjustment I'll regret due to lack of understand.

Is what Ive outlined in the pic correct.

Thanks

AL

Offline ALPH1

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Re: BSA A10 Breather Replacement - Advise
« Reply #13 on: 17.09. 2019 16:45 »
Hey RDfella. it came out but only slightly and Im almost it when back on the same teeth. Is it ok to rotate, as someone said not to.. Move  via the nut of kick or does it mater.

Thanks

Al

 

Offline chaterlea25

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Re: BSA A10 Breather Replacement - Advise
« Reply #14 on: 17.09. 2019 19:03 »
Hi and welcome Al,
It would have been good if you checked the breather sleeve for play before dismantling

Once set the timing marks will only line up again after  xx  number of turns because the idler wheel has an odd tooth count not the same as the cam,

John
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