Author Topic: Oil from breather pipe  (Read 541 times)

Offline TT John

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Oil from breather pipe
« on: 07.03. 2016 15:24 »
I have just reset the tappets on my A10 Golden Flash, after replacement of rockerbox gaskets, started up the bike all went okay, I checked that the oil was returning to the tank, all going well for about three minutes then all of a sudden it started spurting out oil from the breather tube, as much as there was, going to the oil tank.
Any ideas from the forum, *????* as to what the cause of this is, I will check the crank breather cork and the oil pump later.

Online bsa-bill

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Re: Oil from breather pipe
« Reply #1 on: 07.03. 2016 16:15 »
breather on the oil tank or breather from the crankcase?
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline TT John

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Re: Oil from breather pipe
« Reply #2 on: 07.03. 2016 16:52 »
I was thinking the timed breather in the crank case.

Offline muskrat

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Re: Oil from breather pipe
« Reply #3 on: 08.03. 2016 07:51 »
I'm waiting for an answer to Bill's ?
If oil tank breather, the tank was topped up and then got topped up again by the oil that had gathered in the sump from "wet sumping" causing the over flow.
If the crankcase breather, the scavenge side of the pump can't keep up. Could be a crimped or partially blocked line, too much going to the rockers. Has the inner timing cover been removed lately? Timed breather cork too thin, pin not meshed properly.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline TT John

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Re: Oil from breather pipe
« Reply #4 on: 08.03. 2016 08:54 »
Muskrat. No, the oil tank was not topped up, I have an isolation tap on the oil feed pipe, which is turned off when the bike is in the shed, the timing cover was removed to re-gasket due to slight leak, so there is two things to my mind, as you say cork on the timed breather too thin or,  obstruction in the scavenger pump. I will be working on it today all being well and hope I can find out the answer but it's always good to hear other members opinions and I do value these, many thanks.

Regards TTJohn

Offline TT John

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Re: Oil from breather pipe
« Reply #5 on: 08.03. 2016 14:15 »
Well, I've stripped the timing chest out , found that I was out one tooth on the gear, which could have been the problem but after putting it all back together, new gasket on the oil pump, it is virtually the same except that  the oil coming out of the breather is foaming up and there is very little coming back on the return at the tank, do you think the pump is past its sell by date?
Thoroughly p###ed off now.

TTJohn

Online bsa-bill

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Re: Oil from breather pipe
« Reply #6 on: 08.03. 2016 16:16 »
Quote
found that I was out one tooth on the gear

now is that the idler gear which you line up the marks at TDC when putting the engine together (after having had the pinion off) to time the valves, after that it takes around 70/80 turns for it to line up again, in between it can be anywhere.
If it was out you'd have the possibility of valves kissing pistons.
or are you talking about some other gear
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline TT John

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Re: Oil from breather pipe
« Reply #7 on: 08.03. 2016 16:26 »
Bill, I think I sussed at last, stripped down again, oil pump stripped and checked, removed the oil pipes and blew out with air line, re-assembled stuck it back together, started up and got a nice return in the oil tank.
The gear I was referring to is the one between the crank pinion and the mag pinion, as you say it only lines up every 80 revolutions

Online bsa-bill

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Re: Oil from breather pipe
« Reply #8 on: 08.03. 2016 18:24 »
 nice one - well done
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline muskrat

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Re: Oil from breather pipe
« Reply #9 on: 08.03. 2016 18:53 »
G'day John.
So it's possible there was crud in one (return) of the oil lines? I'd be looking further. Check the sump plate strainer and also cleaning out the oil tank, especially the stand pipe.
Timing the gears is as Bill says. If you have to move the cam pinion to get it all lined up, do it with the piston down the bore a bit so as not to touch a valve on the piston.
Cheers 
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7