Crankcase breathing - Page 2

Mr Gazza · 09-11-2019, 04:47 PM

It looks like you've found the smoking gun, so to speak.

The plug looks like it has a burnt oily deposit and the piston crown appears to have a very heavy deposit also.

That indicates Flips excellent diagnosis would be correct. The problem might be gummed rings, or worst case scenario, broken rings! Or it could be the inlet guide seals.

Reddex might un-gum a stuck ring and also go some way to clearing the deposit on the piston (and the rest of the combustion chamber), but a broken ring would need a top end strip and a new ring(s), plus a de-coke while you're in there.

The valve seals are relatively easy to change, so long as you don't lose the valve down the cylinder. I'm not sure if they drop right through if the piston is at TDC, but I believe that filling the combustion chamber with string through the spark plug hole can save it from dropping. Another method is to fill the cylinder with air via an adapter in the plug hole... Obviously the rings need to be in good order for this to work. About 100psi is needed apparently.

Finally... As Flip says, use it more..

the lodger · 10-11-2019, 09:24 AM

Has anyone come across gummed rings on a modern bike using modern fuels and oil, which is used regularly ? I would love this to be the problem but I think it's optimistic.
However it's worth a go so any recommendations for a suitable Redex or similar ?

Mr Gazza · 10-11-2019, 09:42 AM

"Regularly?"
Redex seem to sell a beguiling range of products now! It used to just be upper cylinder lubricant.
I would be tempted to try the Petrol system cleaner. Just shoot a couple of caps full into the spark plug hole of a warm engine, then kick it over a few times. (Doh! fit a kickstarter!), leave for a week or whatever to soak, then start and enjoy the smoke screen!

jerry · 11-11-2019, 09:20 AM

All i know is that with emmissions canister and pipe to airbox my monster 750 and S4 both get mayonaise in the sight glass even on HOT days the S4 is in Thailand so very hot ,,but with a little K&N type filter on the engine they dont get this issue.

The New 1997 Monster has a K&N on the end of the plastic emmisions box under the seat with only the pipe to the airbox ,,, it get mayonaisse on cold days in UK ,,

The 750 SS still has the full emmisions fitted all the way to the irbox but never gets mayonaise ???

Flip · 11-11-2019, 09:16 PM

I've heard of a few various concoctions being used to try and free off stuck piston rings without stripping the motor but I don't have any experience of them personally.

Everything from proprietary lubricants such as Red-X as Mr G mentions to pouring Diesel in through the plug hole and leaving it a few days with the theory being that the moment it doesn't disappear then the rings are freed and the seal has been re-made.

Obviously anything that get past the rings and into the crankcase would need to be drained out before starting and it would be wise to give the motor a couple of oil changes before feeling settled it was back to normal.

As for 'mayonnaising'- mine never suffered too badly from it with the factory set-up but since removing the 'warm air' return pipe from the catch tank to the air box it never does when it has a run out now whatever the ambient temperature is.

Luddite · 11-11-2019, 11:08 PM

Quote:

Originally Posted by Flip

I've heard of a few various concoctions being used to try and free off stuck piston rings without stripping the motor but I don't have any experience of them personally.

Everything from proprietary lubricants such as Red-X as Mr G mentions to pouring Diesel in through the plug hole and leaving it a few days with the theory being that the moment it doesn't disappear then the rings are freed and the seal has been re-made.

Various cocktails discussed here...

http://www.ukmonster.co.uk/monster/s...ad.php?t=56829

09-11-2019, 04:47 PM	#16
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,793	It looks like you've found the smoking gun, so to speak. The plug looks like it has a burnt oily deposit and the piston crown appears to have a very heavy deposit also. That indicates Flips excellent diagnosis would be correct. The problem might be gummed rings, or worst case scenario, broken rings! Or it could be the inlet guide seals. Reddex might un-gum a stuck ring and also go some way to clearing the deposit on the piston (and the rest of the combustion chamber), but a broken ring would need a top end strip and a new ring(s), plus a de-coke while you're in there. The valve seals are relatively easy to change, so long as you don't lose the valve down the cylinder. I'm not sure if they drop right through if the piston is at TDC, but I believe that filling the combustion chamber with string through the spark plug hole can save it from dropping. Another method is to fill the cylinder with air via an adapter in the plug hole... Obviously the rings need to be in good order for this to work. About 100psi is needed apparently. Finally... As Flip says, use it more.. __________________

10-11-2019, 09:24 AM	#17
the lodger Registered User Join Date: Oct 2019 Location: Chorley Bike: M900 Posts: 160	Has anyone come across gummed rings on a modern bike using modern fuels and oil, which is used regularly ? I would love this to be the problem but I think it's optimistic. However it's worth a go so any recommendations for a suitable Redex or similar ? __________________ Contents may settle !

10-11-2019, 09:42 AM	#18
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,793	"Regularly?" Redex seem to sell a beguiling range of products now! It used to just be upper cylinder lubricant. I would be tempted to try the Petrol system cleaner. Just shoot a couple of caps full into the spark plug hole of a warm engine, then kick it over a few times. (Doh! fit a kickstarter!), leave for a week or whatever to soak, then start and enjoy the smoke screen! __________________

11-11-2019, 09:20 AM	#19
jerry Old Git Join Date: May 2006 Location: Cricklade Bike: Multiple Monsters Posts: 2,803	All i know is that with emmissions canister and pipe to airbox my monster 750 and S4 both get mayonaise in the sight glass even on HOT days the S4 is in Thailand so very hot ,,but with a little K&N type filter on the engine they dont get this issue. The New 1997 Monster has a K&N on the end of the plastic emmisions box under the seat with only the pipe to the airbox ,,, it get mayonaisse on cold days in UK ,, The 750 SS still has the full emmisions fitted all the way to the irbox but never gets mayonaise ??? __________________ MONSTERMAN

11-11-2019, 09:16 PM	#20
Flip Registered User Join Date: Mar 2010 Location: Beachtown Bike: M900 Posts: 2,188	I've heard of a few various concoctions being used to try and free off stuck piston rings without stripping the motor but I don't have any experience of them personally. Everything from proprietary lubricants such as Red-X as Mr G mentions to pouring Diesel in through the plug hole and leaving it a few days with the theory being that the moment it doesn't disappear then the rings are freed and the seal has been re-made. Obviously anything that get past the rings and into the crankcase would need to be drained out before starting and it would be wise to give the motor a couple of oil changes before feeling settled it was back to normal. As for 'mayonnaising'- mine never suffered too badly from it with the factory set-up but since removing the 'warm air' return pipe from the catch tank to the air box it never does when it has a run out now whatever the ambient temperature is. __________________ You're perfect, yes, it's true- But without me you're only you!