The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: ALPH1 on 17.09. 2019 10:17

Title: BSA A10 Breather Replacement - Advise
Post by: ALPH1 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.     
 
Title: Re: BSA A10 Breather Replacement - Advise
Post by: Greybeard 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.
Title: Re: BSA A10 Breather Replacement - Advise
Post by: muskrat 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
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 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!!
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 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

 
Title: Re: BSA A10 Breather Replacement - Advise
Post by: berger 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
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 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
Title: Re: BSA A10 Breather Replacement - Advise
Post by: berger 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
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 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

Title: Re: BSA A10 Breather Replacement - Advise
Post by: Greybeard 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.
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 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
Title: Re: BSA A10 Breather Replacement - Advise
Post by: RDfella 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.
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 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
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 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

 
Title: Re: BSA A10 Breather Replacement - Advise
Post by: chaterlea25 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
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 17.09. 2019 19:26
WOW thanks John,, I should have been reading this while spinning that thing over and over *smile* I was sure is was never going to line up again. Yeah thats the issue with discovery as you go.. You only know youve made a mistake after you have done up but hey, this morning I didnt know what was under the cover and now I do thanks to all the help. The cork washer does have to much play so it needed dismantlement anyway and the fear has left!


Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 17.09. 2019 19:52
WOW thanks John,, I should have been reading this while spinning that thing over and over *smile* I was sure is was never going to line up again. Yeah thats the issue with discovery as you go.. You only know youve made a mistake after you have done up but hey, this morning I didnt know what was under the cover and now I do thanks to all the help. The cork washer does have to much play so it needed dismantlement anyway and the fear has left!





Title: Re: BSA A10 Breather Replacement - Advise
Post by: Greybeard on 17.09. 2019 19:56
I think you have it timed ok by those photos  *smile*
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 17.09. 2019 20:00
Yeah thanks Greybeard! Id do it again now *smile*

john, you based in Ireland.. Myself included.

Al

Title: Re: BSA A10 Breather Replacement - Advise
Post by: duTch on 17.09. 2019 20:17

 Hiya Alphi- as John stated and regarding previous ideas, for future reference, and if nothing moved while the idler is unmeshed, the process can be shortened somewhat by simply rotating it all just enough-should be no more than two crank revolutions- to have the marks on the **camshaft and crank pinions** in the correct orientation (without needing the idler marks anywhere near), then just pull the idler out and re-align the marks to check if it's correct.....as John suggests I think I read somewhere the magic number of rotations between alignments is 97, but that's from the back row of my neurons *eek*.

 As discussed in another recent thread, some of us use a gasket paper shim the right thickness behind the cork to pack it out...(also taking into account the cover gasket thickness)
Title: Re: BSA A10 Breather Replacement - Advise
Post by: muskrat on 17.09. 2019 20:58
G'day Alph.
Good to see you got a handle on this now. I'd replace the dynamo cork as well. That compartment has grease for the chain.
Now get over to introductions and tell us your story.
Cheers
Title: Re: BSA A10 Breather Replacement - Advise
Post by: chaterlea25 on 17.09. 2019 22:42
Hi Al,
Yup, In the Peoples Republic of Cork

While you have the covers off check for vertical and in out movement on the crank end
1 1/2 thou vertical and a max of 3 thou in out

John
Title: Re: BSA A10 Breather Replacement - Advise
Post by: Swarfcut on 18.09. 2019 08:43
Al, As a precaution I would remove the sump plate and clean the filter gauze, also check the little ball valve is free to move. Remove the oil tank and oil lines, clean and blow through. Be careful to reconnect the pipes correctly, the crankcase is marked F...Flow and R ....Return. Refill with the correct recommended quantity of fresh oil. Reading your first post would indicate to me that the scavenge side of the oil system is not working properly, or that the system is overfull. The first sign of this is a smoky exhaust, and oil being dumped through the breather. When running, the oil level in the tank should stay the same, or even rise slightly as the pump returns oil which accumulates in the engine sump. As mentioned, the dynamo chain is tensioned by slackening the dynamo strap and rotating the body. Pull the dynamo towards you to trap the cork sealing washer between the inner timing cover and dynamo, replace the grease as this is the only lubrication the chain gets.


Swarfy.
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 18.09. 2019 09:33
Thanks Swarfy, John, Mustrat, duTch for all the great advise!

Swarfty --good sleuthing and think you have a very good point.
I may have been overly generous with cheap gasket seal due to the rocker cover oil leak and I was thinking some oil passage had become blocked and was contributing to or causing this issue. The oil was returning but did drop in level as it was loosing oil from the breather. The I topped it up a little.

So check list:
remove sump plate clean filter
I had the ball valve out but I'll check that again
place oil - verify quantity.. Was sure I had this right at 4 1/4 pints. will double check that for sure!
Blow out lines flow and return. I tipped this blue and red dots as never noted the marks before
Remove oil tank and clean all lines and filters.
Replace grease 1/2 LB is If im right.

Thanks Guys!

AL

   

   
Title: Re: BSA A10 Breather Replacement - Advise
Post by: Swarfcut on 18.09. 2019 13:53
Grease to reach about halfway up the big sprocket....that's plenty.
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 18.09. 2019 15:41
all back in and turning over OK. no jamming up and seems smooth now on to cleaning all the oil pipes.

John.. Could not find any play on the shaft. This normal?

Thanks
Al
Title: Re: BSA A10 Breather Replacement - Advise
Post by: Swarfcut on 18.09. 2019 16:07
The ball valve on the scavenge pipe in the sump is fixed, so if we are talking about the same valve, the pipe  should be firmly sealed into the crankcase drilling. A leak here means the pump will suck air instead of oil. The ball should be free to move, and the valve should not be able to be removed.

The figures quoted by Chaterlea John are a sort of ball park figure for a well used engine. Any less is a good sign. Looks as if you have no appreciable play with a cold engine, so that is a reasonably good motor.
Title: Re: BSA A10 Breather Replacement - Advise
Post by: chaterlea25 on 18.09. 2019 16:22
Hi Al,
Quote
John.. Could not find any play on the shaft. This normal?
*smile* *smile* *smile* Great

Quote
The figures quoted by Chaterlea John are a sort of ball park figure for a well used engine. Any less is a good sign. Looks as if you have no appreciable play with a cold engine, so that is a reasonably good motor.

+1

That never happens to me, Everything that arrives here is shagged out  *problem* *problem* *problem*
(or seized) *sad2*

The new breather cork should be under a little compression when fitted, I have found new corks can shrink after some use and the breather goes slack
Too tight and the sleeve wears the timing case


John
Title: Re: BSA A10 Breather Replacement - Advise
Post by: Greybeard on 18.09. 2019 16:23
The ball valve on the scavenge pipe in the sump is fixed, so if we are talking about the same valve, the pipe  should be firmly sealed into the crankcase drilling. A leak here means the pump will suck air instead of oil. The ball should be free to move, and the valve should not be able to be removed.


Yes, this did worry me!
Quote
I had the ball valve out but I'll check that again

Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 18.09. 2019 18:12
Oh! so what I was taking about was the pressure release valve :) double nut,spring and small bearing to the front of the case.

Thanks

Al
Title: Re: BSA A10 Breather Replacement - Advise
Post by: Greybeard on 18.09. 2019 19:28
Oh! so what I was taking about was the pressure release valve :) double nut,spring and small bearing to the front of the case.

Thanks

Al
Ah, ok, that's the PRV, (Pressure Relief Valve).
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 18.09. 2019 21:20
all oil ways cleaned and blown out.. have it back together just need to top up with oil and fire it up.. I found nothing in the oil that added up to a blockage so Im hopeful I either over filled it or the washer was the cause.. I'll update tomorrow!! Not much done in my other job today!!  *smile*

Thanks

Al   
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ironhead on 18.09. 2019 22:20



That never happens to me, Everything that arrives here is shagged out  *problem* *problem* *problem*
(or seized) *sad2*



   Ditto
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 19.09. 2019 14:49
SUCCESS!! Not a drop of oil coming from the breather!! Only ran on the stand but it was coming out like a fire hose last time!

She's running lumpy and still erratic idle but Im sure a tune of of the carb will the root cause of that.

Guys thanks a lot for all the advise and help, hopefully this thread helps others like me in the future!

Thanks

Al




 
Title: Re: BSA A10 Breather Replacement - Advise
Post by: Greybeard on 19.09. 2019 15:05
...erratic idle....
I'd prefer an erotic idyll  ;)
Title: Re: BSA A10 Breather Replacement - Advise
Post by: ALPH1 on 19.09. 2019 15:27
 *smile* *smile* *smile* *smile*