valve stem seals ? leaking

MEDOGROCKET · Jun 9, 2008

Hello all

I suspect my 06 550 has a valve stem seal which is leaking, upon starting from cold after sitting for a couple of days, she blows smoke for up to 15-20 seconds then clears up, once warm and running there is no sign of oil smoke. The bike had a rebuilt about 35 hours ago due to failed mains, I can only assume there was no work performed on the head, the bike has done 124hrs total
This smoke has appeared from nowhere and has happened about 6 times now and appears to be getting worse.
Is there anyway of checking this is the cause and can the seal be replaced safely without removing the head

Taffy · Jun 9, 2008

you can't replace the seal without removing the head i'm afraid. i don't think it's the seal. when your mains went did the engine FRAG in anyway?

i have a 470 here which sprayed all the balls around from the waterpump shaft bearing. they hit the underside of the piston so hard that the oil ring gap was crushed over the GP area and the oil ring was stuck deep in it's groove.

i hope this isn't the problem.

one check you can make for guide seals is simply to remove the exhaust headers and the carb and inlet spigot. with dry hands rub your fingers around the guides and do a visual with a torch. the exhaust side will look wet on soot and is easier to view anyway.

regards

Taffy

MEDOGROCKET · Jun 9, 2008

Thanks mate
piston, rings, sleeve are all new.
I did not even think about simply having a look in the inlet and exhausts, i'll do that and hope to confirm my thoughts.

awilksch · Jun 9, 2008

good luck timmy, hope its only a minor hiccup.

you havent had your bike upside down or on its side recently have you? sometimes the oil wil get right up in to the breather soses to the backbone airbox, then the engine draws oil vapours in, that will do what you describe, but should only do it once or twice, not repeatedly.

I would have thought that you could change valve stem seals withthe head on, but you would need to do what taff has suggested to hold the valves in place - maybe it is getting the valve springs compressed and the colletts back on that is the problem - i'll shut up now and go look at the schematic.

Azza.

AUSBERG · Jun 9, 2008

You can use compressed air via the spark plug hole to hold valves closed when changing springs/seals etc. We used to do this on an L series Nissan race engine years ago.

But for the small bit of effort involved as the rocker cover etc is already off, I'd just remove the head.

faktor · Jun 10, 2008

here here Ausberg.....

whosahberg · Jun 10, 2008

yes ... i used the technique ausberg described to change springs recently

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valve stem seals ? leaking

MEDOGROCKET

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