Author Topic: engine oil loss and smoke  (Read 976 times)

Offline RDfella

  • Resident Legend
  • *****
  • Join Date: Aug 2017
  • Posts: 626
  • Karma: 5
engine oil loss and smoke
« on: 21.07. 2018 17:40 »
How you guys put up with these A series bikes baffles me. Had many bikes - including several BSA's - during over 50 yrs riding, but never had as much trouble as I'm getting with this '58 G.F.
Bike has been completely rebuilt. Almost concours (except TLS and s/s rims). Engine completely rebuilt - rebore, new bearings, cam, valves, valve seats etc. Had trouble with the oil pump - which you guys kindly pointed me to the oil pump gasket having too-small holes. It then ran fine with substantial oil return flow. Ran it in all for perhaps 20 minutes. No smoke, all OK.
Fast forward. Today, thought I'd take it for its first ride. Drained sump (not much from standing) pumped tyres, add petrol. Started 2nd kick. But the smoke. Jeez, unbelievable. Worse than a smoke bomb. And oil pouring out from, it seems, behind the primary case. I mean pouring out - an egg cup full every two or three seconds. Return to tank is a strong flow and it didn't do this before. I've know wet sumping from bikes being left a while. Either drain the sump or rev it a bit, but this is ten times worse.
As I said, never had so much trouble with any bike. And I haven't even ridden it yet. I'm so pyssed of with it that if this isn't an easy two-minute fix, I'm going to part it out. BTW, I'm an experienced engine designer and rebuilder.
Any ideas, folks?
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 5795
  • Karma: 32
Re: engine oil loss and smoke
« Reply #1 on: 21.07. 2018 17:56 »
Here's a thought: After I'd not ridden my bike for some months I topped up the oil tank and drove 40 miles. Oil PEED out of the breather pipe, (behind the primary case) and converted my left  boot into lovely shiny patent leather! Why? Because I'd forgotten that the reason the oil was low in the tank was that it was in the sump. Running the engine, the pump was doing what it is supposed to do. The oil tank overflowed pouring oil out of the breather. It's one of those schoolboy errors that one never forgets, (I hope).

Offline mugwump

  • A's Best Friend
  • ***
  • Join Date: Jan 2016
  • Posts: 103
  • Karma: 0
Re: engine oil loss and smoke
« Reply #2 on: 21.07. 2018 18:20 »
Flow and return oil pipes reversed. Broken oil control ring or rings upside down.

60'Matchy G12
58 AJS 18s
58 Ariel Huntmaster]

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5362
  • Karma: 61
Re: engine oil loss and smoke
« Reply #3 on: 21.07. 2018 18:57 »
Quote
Broken oil control ring

had this recently and boy did it smoke
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

Online Triton Thrasher

  • Scotland
  • Wise & Enlightened
  • *
  • Join Date: Feb 2009
  • Posts: 1466
  • Karma: 20
Re: engine oil loss and smoke
« Reply #4 on: 21.07. 2018 18:57 »
  I'm an experienced engine designer and rebuilder.

Good job you told us.

Online Beeza

  • A's Best Friend
  • ***
  • Join Date: Oct 2014
  • Posts: 101
  • Karma: 3
Re: engine oil loss and smoke
« Reply #5 on: 21.07. 2018 19:20 »
Just a check... Pop the sump plate off again and check that the ball in the pick up is not stuck down. I have seen this to pump the oil out the breather (behind the primary).

Offline berger

  • Resident Legend
  • *****
  • Join Date: Nov 2017
  • Posts: 873
  • Karma: 6
  • keith from chesterfield 500ss cafe morris 8
Re: engine oil loss and smoke
« Reply #6 on: 21.07. 2018 19:42 »
i have not been to the pub, did you just undo a drain plug? I did that once some years ago and got a cup full. I started the engine and it poured out of the breather and filled the mag because it was still full, pulled a vacuum I think, the next time I took the plug out I let it drain then kicked it over and got a bucket full.or as above the ball is stoooook

Offline worntorn

  • Valued Contributor
  • ****
  • Join Date: Jun 2015
  • Posts: 376
  • Karma: 2
Re: engine oil loss and smoke
« Reply #7 on: 21.07. 2018 19:46 »
Gawd, I've got an A10 and with the mag fixed it's been so reliable it's almost boring.

No, I take that back, no bad karma please,not bored at all, reliable is good
Glen

Offline Black Sheep

  • Resident Legend
  • *****
  • Join Date: Apr 2017
  • Posts: 619
  • Karma: 6
    • Where black sheep live
Re: engine oil loss and smoke
« Reply #8 on: 21.07. 2018 20:33 »
It's the total rebuild that bothers me. The A series engine is a good, solid, reliable lump. This needs careful investigation. Compression check for starters. Could the oil control rings have broken on replacing the barrels? Is the breather assembled properly? Clearly something was not put together properly.
2 twins, 2 singles, lots of sheep

Offline RDfella

  • Resident Legend
  • *****
  • Join Date: Aug 2017
  • Posts: 626
  • Karma: 5
Re: engine oil loss and smoke
« Reply #9 on: 21.07. 2018 20:41 »
Thanks to all who have replied so far. It's not piston rings - even if they were left out it wouldn't be this bad. In fact I'm amazed it didn't foul the plugs. Not oil pipes reversed - they are right and haven't been touched since it ran OK previously. Indeed, nothing has been touched at all, save draining sump to check for wet sumping. Checked oil level in tank and it seemed about right.
Will drop the plate this time and see what gives (it has an alloy sump plate with magnetic drain bung). I've had engines run when wet-sumped many times over the years - usually a bit smokey and sluggish, but this is ridiculous. If you ran it for three seconds you wouldn't see a car behind you. Are these engines prone to this? As stated, have owned many bikes over the years - and still have a few - but never had this much grief with one bike. And do these bikes have a tall first gear? The gearbox and mainshaft sprokets are std. but first is higher than first in my racing B31 with its CR gearbox.
Used to ride a rigid A7 in the early 60's but otherwise my twins have either been vee or Triumph (6t Triton) so am not impressed with this A10.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Offline muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8066
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: engine oil loss and smoke
« Reply #10 on: 21.07. 2018 21:48 »
G'day RDfella.
Smoking both sides or one? If it didn't foul the plugs with that much smoke I'd say ex valve guides. Were they replaced? And bronze or cast iron?
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: engine oil loss and smoke
« Reply #11 on: 21.07. 2018 22:09 »

 
Quote
....... Are these engines prone to this?.......
    Generally not, but maybe sometimes... My first thought is as BlackSheep suggests- maybe the breather is not sealing properly.

 When I change the oil, I have about 170ml after I drop the sump plate (immediately after a ridearound), I guess that'd be about standard.
 
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline chaterlea25

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 3117
  • Karma: 45
Re: engine oil loss and smoke
« Reply #12 on: 21.07. 2018 22:14 »
Hi RD,

Quote
Ran it in all for perhaps 20 minutes. No smoke, all OK.

Quote
Fast forward. Today, thought I'd take it for its first ride

Does that mean you ran the engine for 20 minutes stationary?
Thats well long enough to glaze the bores  *eek*

You do not say what oil you used ? the wrong oil can make problems with a "new" engine

+1 on the other replies,

The magnetic drain plug can make the return ball stick if the plate is fitted with the plug near the pickup
Been there and had that happen *problem* *problem*

John
1961 Super Rocket
1963 RGS (ongoing)

Offline Black Sheep

  • Resident Legend
  • *****
  • Join Date: Apr 2017
  • Posts: 619
  • Karma: 6
    • Where black sheep live
Re: engine oil loss and smoke
« Reply #13 on: 21.07. 2018 22:39 »
I can leave the A10 or A7 standing for weeks, months even, and they start without smoking or widdling oil everywhere. These bikes are bog standard and well used. It does sound like you are pressurising the crankcase somehow. As I alluded to previously, once put together properly these engines run and run indefinitely with minimal maintenance. An old bike is only as good as its last rebuild. 
2 twins, 2 singles, lots of sheep

Offline kiwipom

  • Resident Legend
  • *****
  • Join Date: Jan 2011
  • Posts: 751
  • Karma: 8
Re: engine oil loss and smoke
« Reply #14 on: 21.07. 2018 22:55 »
hi R.D, probably a simple fix really these machines are not `Rocket Science` as black sheep says(Clearly something was not put together properly) but patience is required and you being (an experienced engine designer and re builder) should have no problems, good luck, cheers
A10.G.Flash(cafe racer)Honda 250 vtr. Yamaha Virago XV920.

War! what is it good for?Absolutely nothing, Edwin Star.
NewZealand