Oil consumption

[Dmitry]

Hey forum I have a question about my Monster M900 (1997 year). Oil consumption = 300 milliliters per 1000 miles. It is normal for this air cooled engine or not? Oil: Motorex Top Speed 4T 10W40.
Pressure in the engine = 150 psi with open throttle. I injected a tablespoon of oil into the spark plug hole and pressure went up to 175 psi. This is very bad? It's time to change piston rings or valve stem seals? Or change all of this

[ducpainter]

IMHO that is perfectly normal...run it

[Howie]

Also make sure you are not doing too good of a job keeping the oil topped up.  Bike vertical, oil warm, between the add and full?  Do not top up!

[Dmitry]

Also make sure you are not doing too good of a job keeping the oil topped up.  Bike vertical, oil warm, between the add and full?  Do not top up!

I know about it. But still, this oil consumption for M900 is normal or bad? It is time to change piston rings and valve stem seals or it is feature of this air cooled engine? Mileage: 19 250 miles.

[Howie]

I would call it less than average but not enough to be concerned about as long as you do not see blue smoke and the engine runs smoothly.  Compression is good.  You might look at the condition of the valve seals next valve adjustment.  You can check for guide wear at the same time.  For now, 

Also, keep in mind riding style affects oil consumption.

[Frank C]

To give you a point of reference...
I also have a 97 900 and use about 0.5 liter per 1000 miles.
150 psi on horizontal.  125 psi on vertical.  Over 35k miles on engine.
I also have flatsides, larger cams and valves, and beat the piss out of it.

Hope that helps....

[Dmitry]

I would call it less than average but not enough to be concerned about as long as you do not see blue smoke and the engine runs smoothly.  Compression is good.  You might look at the condition of the valve seals next valve adjustment.  You can check for guide wear at the same time.  For now, 

Also, keep in mind riding style affects oil consumption.

"I would call it less than average"
You want to say, that even healthy engine on Monster M900 requires constant to add oil every 1000 miles? Because it air cooled engine and all that.

[Howie]

You are talking 300 milliliters in 1000 miles.  less than a a liter in 3000 miles.  Considering VW/Audi, who are amongst the more liberal when it comes to excessive oil consumption under warranty uses the guideline of about a liter in 1000 miles you are doing OK.  Also try maintaining the level between the add and full mark, not topped up.

[jduke]

My 2001 M900Sie has over 25,000 miles and uses zero oil in between oil changes every 3,000 miles. I use whatever synthetic oil is the cheapest at Auto Zone / Advance Auto when I'm about to do an oil / oil filter change.
Like was said earlier, if you aren't seeing smoke out the exhaust, then check the valve guides. You're loosing too much oil in my opinion than normal.

[koko64]

I have consistently read about and seen the difference between earlier carbed motors and later model motors due to model changes in pistons and rings. There have also been changes in valve guide and stem seal material over model years. So normal varies and so does oil consumption plus all the other factors. 300 ml use for that model aint too bad. Some will know the details on the changes over model years.

[Dmitry]

I have consistently read about and seen the difference between earlier carbed motors and later model motors due to model changes in pistons and rings. There have also been changes in valve guide and stem seal material over model years. So normal varies and so does oil consumption plus all the other factors. 300 ml use for that model aint too bad. Some will know the details on the changes over model years.

I injected a tablespoon of oil into the spark plug hole and pressure went up to 175 psi from 150 psi. Your opinion: it means that the piston rings are bad? Or 25 psi it is not a difference to think so.
Sorry for my bad English

[Howie]

If your rings were bad you would be reading less than 150 PSI.  Normal wet test is one teaspoon, not one tablespoon.  Olde expression "If it ain't broke don't fix it".  Your English is fine.

[Dmitry]

If your rings were bad you would be reading less than 150 PSI.  Normal wet test is one teaspoon, not one tablespoon.  Olde expression "If it ain't broke don't fix it".  Your English is fine.

I am looked valve stem seals. Watch this video:
I do not know. Maybe I showing incorrectly. How to identify, it soft or hard? Or I must to change when valve stem seals will like stone

[Howie]

As I said, Olde expression "If it ain't broke don't fix it"

[Dmitry]

As I said, Olde expression "If it ain't broke don't fix it"

I understood you. Thanks for answers