Author Topic: Engine breather  (Read 1109 times)

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Spaceman

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Re: Engine breather
« Reply #15 on: 16 August, 2022, 23:21:14 »
What's a 'tin plate' sprocket cover? We're not talking about a very big hole in the back of the chaincase are we?

TTJOHN

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Re: Engine breather
« Reply #16 on: 17 August, 2022, 08:19:50 »
Mike forget about an additional breather tube, get to the crux of the matter, if you are getting access pressure, it's because your piston rings are letting by. I had the same problem, the only way round it is to check your pistons & rings, I have now sorted mine with new pistons, cylinder and rings.

TTJohn

Mike Farmer

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Re: Engine breather
« Reply #17 on: 17 August, 2022, 17:15:14 »
 :) :) :) :)

Yes we are talking about the big hole which has a tin plate (actually on my others its stainless) cover secured on the gearbox side of the casing with 3off  (4??) 2BA screws.

TT John  Brand new pistons and rings, rebored. Maybe its a bedding in thing. As I said this one can go to bye byes whilst I get around the inner cover problem. When I do something stupid, its for real.

My wife said NO to new Goldstar. So shant buy one just yet.

Probably early next year. We'll see.
 
MIke 8) 8) 8) 8)

Mike Farmer

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Re: Engine breather
« Reply #18 on: 17 August, 2022, 17:25:20 »
 :) :) :) :)

The Tin Plate is Pt No 68-0360 The part is still in the box. Ho Ho Ho

Mike 8) 8) 8) 8)

Spaceman

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Re: Engine breather
« Reply #19 on: 17 August, 2022, 18:33:33 »
I misinterpreted what you were referring to - I think all that this cover plate does is to protect the engine casing from the rear chain and obviously has nothing to do with the oil leak? Not really sure why it's there

Mike Farmer

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Re: Engine breather
« Reply #20 on: 17 August, 2022, 20:25:57 »
 :) :) :) :)
I'm inclined to go along with TT and think maybe new pistons not bedded etc. In fact I think Dave suggested such when I first mooted this problem a couple of years back.

As said we'll see I certainly not gonna lose a lot of sleep over it. However has anyone ever fitted one without taking the motor out.

Mike

Spaceman

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Re: Engine breather
« Reply #21 on: 18 August, 2022, 06:52:59 »
I would have thought the cover plate would insert into position from below - it would be easy to check. It appears to be held in by 3 screws. The bottom 2 look to be a bit fiddly from underneath in the bottom of the plate but hopefully there will be enough clearance to get your hand in. The top one may be accessible above the back of the engine with a bit of luck.

I can't honestly remember bolting on the cover plate when I restored my A65 but will have a look later to see if the screws are now accessible.

DAVE BRADY

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Re: Engine breather
« Reply #22 on: 18 August, 2022, 06:56:46 »
Hi,

No plate on either of my A65s.   Although it is probably meant to keep road dirt out it can also serve to trap it. I have not noticed any build up of road dirt.   Also, if you ever have a problem with feeding a chain over the sprocket the plate can get in the way.

Dave.

Spaceman

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Re: Engine breather
« Reply #23 on: 18 August, 2022, 07:51:28 »
The good news is that the screws are as indicated and it shouldn't be a problem re-installing the plate. The bad news is that the plate is missing from my A65 - I obviously didn't notice it should have been fitted when I did the restoration and it must have been missing when I bought the bike! As said, not sure what purpose it really serves?

Mike Farmer

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Re: Engine breather
« Reply #24 on: 20 August, 2022, 22:25:56 »
 :) :) :) :)

I figure it must have a purpose or BSA would not have spent the money putting it there. Seriously tight with their financies.

However I do feel a lot better about forgetting mine.

About feeding chain. My method: - A piece of string with a loop in the endhook it on one tooth of sprocket. use kick start to turn sprocket and hold the string tight onto tooth the string will com right around. When its visible at the bottom, unhook it, tie the chain to it and pull said chain onto sprocket. Hold it tight with the string so it doesnt fall off sprocket and sit in a heap inside casing.

Mike 8) 8) 8)

Spaceman

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Re: Engine breather
« Reply #25 on: 21 August, 2022, 06:35:19 »
It is interesting to compare the A65 with the corresponding 650 cc Triumph twin of the time. Although the primary drive and gearbox configurations are more or less the same, Triumph did not see the need to fit a similar cover plate! You would have thought that if it was needed on the BSA, it would have been needed on the Triumph?

The other thing I notice is that the Triumph twin uses an almost identical timed breather design on the LH end of the inlet camshaft but they went to the trouble of fitting a short metal pipe to the outlet hole so that you could attach a rubber tube to take the output down below the engine. Had BSA adopted this approach, it would have been much easier to tell whether the breather was spewing out oil or not!