Ball bearing in sump

[Worty]

Finished cleaning the bike and threadlocking the screws in the dynamo that had come loose.  Also threadlocked the three large screws around the primary 'bulge' as they'd come loose too (never happened before).  Whipped off the sump and gauze to check - apart from some blobs of hylomar, there was a SINGLE, VERY SMALL ball bearing??????????

Now, this is either, 1) a ball bearing or, 2) an errant piece of metal from my disintegrated ATD thats been rolled around the engine to form a not-perfect spherical ball.

Fascinated to hear your thoughts on this as, 1) I wouldn't expect only one to be there if something had failed and, 2) I would't have thought bearings that small would be employed within the engine.  The 'bearing' is roughly the side of one of the bearings in the dynamo.

[RDfella]

Whipped off the sump and gauze to check - apart from some blobs of hylomar, there was a SINGLE, VERY SMALL ball bearing??????????

If the ball is around 3/16 the only one I can think of is the anti-wet sump ball. But how could it escape? Or is that ball 1/4  - can't remember now. The balls in the clutch (S/A) are around 3/16 but couldn't get into the sump. Mystery.

[Worty]

The ball measures 0.1" or 2.6mm.  Does anyone know the original size of the sump scavenge pipe bearing as, with help from others, we reckon it could be that.  I've only had issues with oil return delay after removing the timing cover which, I assumed, was due to the oil draining out of the pump when the cover was off.  Mind you, I've only just found the bearing so will see if how quickly the oil returns now.  I understand the whole scavenge pipe can be removed and replaced without an engine strip, anyone care to give me some pointers??  Oh, and anyone know where I can get one??

[Swarfcut]

 Timing cover should have no effect on Scavenge performance. Without the cover, oil will simply cascade from the pump area, so less oil to return. With the cover on this oil  passes thro' the keyhole, into the crankcase to be picked up by the pump. A poor oil pump gasket is another possible, a leak here will enable the pump to scavenge from the oil pump cavity as well as the sump, and the pressure side is also marginal in this case. A truly poor design with the feed and return ports so close together.

 S/A Pick up pipe runs horizontally in the cast bulge under the crankcase on the timing side next to the sump plate. Heating this part of the casting will soften the cement used to secure the pick up pipe and with a wiggle and a tug it should pull out.  Give the casting and oilway a good clean out. Reseal the replacement with Loctite and knock it into place.

  Swarfy.

[berger]

i think you have found an oddball , the scavenge and crankcase feed balls are bigger than 2.6mm and so is the cam follower ball can you see the scavenge ball in the pipe with the sump plate off?

[olev]

Gday Worty,
What is your mystery ball made of?
Hit it with a hammer and see if it squashes or breaks.
It sounds like a shotgun pellet.
Have you been behaving yourself?
cheers

[Worty]

Cheers guys.  Like you, I do reckon it's too small to be the scavenge bearing.  Oil does take a short while, maybe 10 seconds to start returning to tank, maybe the ball is a fragment from somewhere else.  Also, how would the scavenge bearing end up on the gauze and not the sump if it fell out.  Surely the bearing would be in the sump as the scavenge pipe goes through the gauze hole?

Took it for an outing today and it ran fine until I headed up to around 70mph when it started to fade and didn't want to play anymore.  Apart from that, and the continuing 'heavy' sound from the engine when hot, it was great - no pinking up the hills, although a bit of a tinkling from the timing side (could be dynamo chain rattle though). 

So, this is the score, run the bike for as long as possible and/or until it needs an engine strip OR flog the bike whilst it's still running and go for something else??  I know the crank is on it's last regrind and the barrels on their last bore, so would be looking at a pretty penny (that I dont' have) to do a full, proper rebuild.

[Slymo]

Sounds like it wants a bit more advance?

[Worty]

Thanks Slymo, I'm running it on 5/16 btdc (or around 8mm in new money).  I use unleaded super with an additive, and it has run well on that.  Are you thinking maybe 11/32?  I understand that widening the c/b gap can advance and closing it can retard to give a better idea of how to set up the timing.  Would it be wise to go down this route.  Could set at 13 thou for advance and 11 thou for retard to see what difference it would make??

[berger]

is the additive octane booster or lead replacement, i tried lead replacement in mine years ago and ended up with massive build up on the crowns that can cause pre ignition.

[Worty]

Both Bergs.  Castol Valvemaster+

[RichardL]

Regarding the ball, this may be an obscure wild-ass idea, but, maybe, check your ratchet wrench handles to be sure the socket retaining balls are in place.

Richard L.

[terryg]

“ Both Bergs.  Castrol Valvemaster+”

Consider switching to Tetraboost. Discussed here a few years ago.

Bergs knows all about it!

Apologies, a bit off topic.