Author Topic: Scavenge pipe blockage  (Read 1081 times)

Offline bobandbec

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Scavenge pipe blockage
« on: 03.12. 2015 22:29 »
Changed the oil and external filter on my A10 on Monday just gone. Kicked it over without the plugs in to get the oil through and then ran it for 10 minutes. Oil was returning back to the tank. All was good.

Came to it this morning and started up. No oil returning to tank and starting smoking which it has never done before.
Took the sump off and there is no sign of the "ball bearing" that sits in the scavenge pipe so assume it is stuck somewhere higher in the pipe. Anyway the pipe is not sucking although there is oil being supplied to the engine.

Any tips on how to get the ball bearing to free itself? And on how to clean out the pipe which I assume is gunged up.

Thanks for any advice.

Peter

Online metalflake11

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Re: Scavenge pipe blockage
« Reply #1 on: 03.12. 2015 23:05 »
Strange one!.......Presuming you have given it a light tap with a screwdriver handle or something I'm a bit stumped!

Try and coax it back down with a magnet? Why has it stuck up there though?

It will be smoking due to wet sumping presumably.

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Online Greybeard

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Re: Scavenge pipe blockage
« Reply #2 on: 03.12. 2015 23:21 »
...Why has it stuck up there though?...
Anal retention?

Offline TT John

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Re: Scavenge pipe blockage
« Reply #3 on: 04.12. 2015 00:02 »
Bob. May be a blast from an air line at the tank return pipe, may do the trick, although I have never heard of the ball being stuck further up the pipe, the onlky other method I would suggest is get a small magnet and try to draw it down.

TTJohn *bright idea*

Offline duTch

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Re: Scavenge pipe blockage
« Reply #4 on: 04.12. 2015 00:13 »

 
Quote
the onlky other method I would suggest is get a small magnet and try to draw it down.

 ..and if you're still stuck (pun not much intended), you might have to remove the oil pump, and blow through there maybe with a bit of solvent (kero/petroleum)...( if you do,obvious you'll have to drain the oil tank first  *eek*)
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
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Online metalflake11

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Re: Scavenge pipe blockage
« Reply #5 on: 04.12. 2015 00:43 »
What oil are you using?....Trying to work out why it got stuck up there in the first place.
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1960 A10
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Online Brian

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Re: Scavenge pipe blockage
« Reply #6 on: 04.12. 2015 00:59 »
Unfortunately this means a engine strip to cure.

There is (should be) a small pin above where the ball sits to stop it doing this. They can wear away with time which allows the ball to get sucked up the pipe blocking it. Its not common but does happen.

Even if you free the ball up as soon as you start the motor it will simply suck it back up the pipe again.

The scavenge pipe has to be either repaired or replaced.

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Re: Scavenge pipe blockage
« Reply #7 on: 04.12. 2015 01:10 »
Unfortunately this means a engine strip to cure.

There is (should be) a small pin above where the ball sits to stop it doing this. They can wear away with time which allows the ball to get sucked up the pipe blocking it. Its not common but does happen.

Even if you free the ball up as soon as you start the motor it will simply suck it back up the pipe again.

The scavenge pipe has to be either repaired or replaced.

Oh dear! *sad2*
England N.W
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Online Brian

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Re: Scavenge pipe blockage
« Reply #8 on: 04.12. 2015 01:31 »
Is the bike a plunger or swingarm model ?

If its a s/arm they have a different scavenge pipe to the plunger and I just had a look at a spare set of cases I have and on the s/arm models it may be possible to get the pipe out without dismantling the engine. I have never done that with the engine in place but it looks like its possible. It will all depend on just how hard the pipe is stuck in the cases.

Online bsa-bill

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Re: Scavenge pipe blockage
« Reply #9 on: 04.12. 2015 10:04 »
Is there not a check valve at the pump end of the pipe so removing the pump might not get you any further, and the little ball itself how does this remain at the end of the suction pipe, can't be just gravity or it would get sucked back every time, tube pinched maybe, sorry more questions than answers tis morning - I'm recovering from man flu ultra at the mo
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 duTch

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Re: Scavenge pipe blockage
« Reply #10 on: 04.12. 2015 11:07 »

 Bill, I don't think there's anything other than what Brian says makes sense;
Quote
...There is (should be) a small pin above where the ball sits to stop it doing this. .....

 I didn't find that, but when I was cleaning mine out, I tried to get the pipe out but but it resisted and I relented...so I settled for doing as I suggested earlier. It seemed to work ok

 Only other thing I thought of later is to maybe run a bit of old clutch or bicycle brake/gear cable down like a plumber/drainer tool, or slip some plastic tube on and suck *eek*.
 
Brian, a pic of those S/A cases would be interesting if possible?

 Pete- maybe I shouldn't ask, but how do you get 'Peter' out of 'bobandbec'..I thought you'd be a Bob *shh*
 
 
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 bobandbec

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Re: Scavenge pipe blockage
« Reply #11 on: 04.12. 2015 15:10 »
Thanks for all the replies and advice.

bobandbec are my two border terriers. Bit misleading I must admit as a name on here.

Anyway it is a 1960 swingarm and was completely stripped etc by the previous owner. Professionally done by a well known outfit.

Went this morning and got underneath with my torch. The ball bearing was stuck only slightly off its seat at the bottom of the pipe. I've had them stuck down before but never stuck up. Got a syringe and gave it a good two lots of petrol squirted up the end of the scavenge pipe and the ball freed itself. Gave it another couple for good measure and aimed some WD40 up into the pipe as well. Didn't seem particularly gungy.

The ball is prevented from going higher up the pipe, as was suggested in one of the posts earlier, but there is nothing actually pushing the ball down from the pump side other than the oil in the pipe I suppose.

Sump plate back on and primed her for a few kicks then started her up and, thank goodness, there was the oil coming back to the tank.
Even managed to get out for a few miles. Seems to be OK but I'll be keeping an even more careful eye on her for a while.

Suppose it could have been a potential disaster if I hadn't checked for the oil return as soon as I started up. A simple thing but a bike saver.

Thanks again to everyone.

Peter

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Re: Scavenge pipe blockage
« Reply #12 on: 04.12. 2015 16:40 »
Suppose it could have been a potential disaster if I hadn't checked for the oil return as soon as I started up. A simple thing but a bike saver.

I'm glad you were able to sort it out. Dry sumpers are advised to always check for a return oil flow; I wonder if everybody always does.

Offline kiwipom

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Re: Scavenge pipe blockage
« Reply #13 on: 04.12. 2015 23:31 »
hi guys, I reckon it probably would have vibrated loose after  short while and after all it is only oiling the rockers the rest of the engine is still getting oil until you empty the tank into the crank case, cheers   
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Online Brian

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Re: Scavenge pipe blockage
« Reply #14 on: 05.12. 2015 05:18 »
Here are a couple of pics of a oil scavenge pipe, you can just make out the head of the pin that goes above the ball.