Forum

[Tim NZ]

It is a simple matter to confirm 100% where the oil in the sump is going from:


Remove timing cover, block off the oil feed from the oil tank with a hardwood peg.


IF there is still oil getting into the sump, it has to be coming through the case, or the case joint...


Next, refit the timing cover but do not fit the Crankshaft oil feed quill bolt...


That will confirm either way if oil is tracking past the gasket and or the oil pump cross shaft into the timing chest...




I presume that you did not repeat the check that oil was not draining from the timing chest?




Which only really leaves the pump disc, its seat and or a damaged timing cover?


By far the most common cause of wet-sumping is at the pump disc face and its seat in the timing cover. Have you 'spot' blued the pump-disc onto its seat? That will show any imperfection in the mating surfaces...

[Bullet Whisperer]

The thing to bear in mind here is it would appear the wet sumping is something which has developed since the top end rebuild and apparently was not a problem before that, so we either have a coincidence on our hands, or, more likely, something has caused this problem when the top end work was done, be it an action, or a component, the culprit is probably in among this top end job somewhere.

[Bullet Whisperer]

Just to add to my last comment - it is possible the engine WAS wet sumping before the top end rebuild, but perhaps the piston rings had been keeping the excess oil away from the combustion chamber on start up and warm up, while the the new rings may, for whatever reason, be letting the oil past and causing the smoke.

[jyrkik]

Hi,

I finally got it sorted - replaced the timings cover and the bike is not smoking anymore.

Before that I tried all possible cures:
-Re-stripped the barrel and checked the piston ring order - they were ok.
-changed the timing cover gasget - no help.
-lapped the oil pumps - no help.
-Replaced the timing gear worm sprocket (the one with neoprene seal) - no help
-Tried to just ride the bike few hunfred kilometers as proposed by many - the smoking didn't get any better/less severe.

But after I changed the timing cover (and lapped the oil pumps to it) the sumping apparently reduced remarkably as now there's only very little smoking when starting the bike first time in the Morning.

It still remains a mystery for me, what was actually wrong with the old timing cover, but who cares. I'm a happy rider again.

Cheers,
Jyrki

[Bullet Whisperer]

By what you describe above, I would be looking for a partial blockage in the scavenge passageway to the oil pump in the old timing cover.