Author Topic: Primary case oil going into the engine/oil tank ?  (Read 1109 times)

Offline chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Hi there fella's. I know what you going to say, impossible. It can't be. But honestly it definatly is. I've topped up the primary case about 6 times, took the bike for a ride, come back, checked oil tank and primary case and every time the oil level in the oil tank has gone up by around 1 an a half inches and the primary case oil has gone down to just below the chain tensioner. Any ideas. Cheers in advance, Chicago
Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.

Offline muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 10754
  • Karma: 130
  • Lithgow NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Primary case oil going into the engine/oil tank ?
« Reply #1 on: 07.05. 2013 21:06 »
 I have had a similar thing when my '51 wet sumped that bad it filled the primary. I drained the sump and topped up the tank. Rode 50 miles and idled, oil pouring out but only at idle. A few revs and it stopped, idle and pumping out again. I think maybe at low revs, not much crank case pressure and the timed breather, the motor was sucking it back in from the primary.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
Muskys Plunger A7

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5720
  • Karma: 66
Re: Primary case oil going into the engine/oil tank ?
« Reply #2 on: 07.05. 2013 21:28 »
Hi Chicago - what are you like with rabbits *smiley4*

My view for what it's worth
As Musky implies, only way for oil to get from the primary to the oil tank is via the sump, has to be suction involved and it's drawn past an oil seal or through a bolt hole.
Also an inch and a half extra in the oil tank is almost more oil than should be in the primary I'm thinking.
Other explinations - petrol - doubtfull and dangerous, - water - just doubtfull - ectoplasm (or someones taking the P---)

No it's a good one this.
I'd suggest draining the primary case, go for a run (short one) then check the oil tank, will prove your right or not

( re reading my words it may seem it's me taking the proverbial, but not intended)
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 chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Re: Primary case oil going into the engine/oil tank ?
« Reply #3 on: 07.05. 2013 22:39 »
Cheers fella's. In the past I've left the primary without topping it up as there's still been enough oil in it to wet the bottom of the clutch basket and the oil level in the tank always stays the same after riding, as soon as I top up the primary and ride it the oil in the tank goes up so hopefully can't be petrol as it only ever happens after topping up the primary, also I've left the bike without topping up the primary or running it for a week or so checked the oil tank level before I start it and again after running it and the oil level doesn't really change that much so I don't think it can be wet sumping that bad. What I did notice a while ago when i was fitting the missing cork washer on the timed breather was that the toothed wheel that the breather sits on looks like somebody has put a thread from a bolt in it to act as a locating pin for the breather but the toothed wheel also had two other holes in it. So if this guy had put this homemade locating pin in the wrong hole could that cause the oil to be sucked into the tank as the timing of the breather would be out. Also since putting the cork washer on I've had a bit of oil come out of the breather tube but when the cork washer wasn't fitted I had no oil come out of the breather tube.
Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.

Offline muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 10754
  • Karma: 130
  • Lithgow NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Primary case oil going into the engine/oil tank ?
« Reply #4 on: 08.05. 2013 11:00 »
 The plungers don't have a crank seal, just a sort of slinger 67-349 called a bearing shim. That's how the oil gets into the primary if she wet sumps badly.
Yes if the breather is closed on the up stroke it will suck any oil splashing around the primary side of the bearing. Say 1/10 of a drop per up stroke, 1/2 hour run at 3000 rpm = 90,000/10 = 9000 @ 10 per ml = 900ml. So you can see it doesn't have to suck much to make a mess.
The cam pinion has two holes 180 deg apart and the peg is somewhere in between. So should be easy to spot if it's wrong.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
Muskys Plunger A7

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5720
  • Karma: 66
Re: Primary case oil going into the engine/oil tank ?
« Reply #5 on: 08.05. 2013 13:58 »
Quote
plungers don't have a crank seal
Thanks lads, the two of you are educating me in the way of plungers, which is good
When you stop learning your dead, or might as well be.
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 chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Re: Primary case oil going into the engine/oil tank ?
« Reply #6 on: 08.05. 2013 17:51 »
Hi, cheers muskrat and bill, thanks to you both for your time and input. I think I'll be taking off the timing side case to check the toothed wheel/cam wheel this weekend, I'll take some photos and update this post for you have a look. Good that I now know where the pin should be, would be good if I could fix both the oil from breather and the oil from primary to oil tank with one small fix, fingers crossed because both these things been bugging me a bit. Hey bill you and muskrat have way more knowledge than I could ever hope to have  *respect*
All the best fella, take care, chicago
Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.