Losing oil

[thrillhouse]

I'm losing oil somehow. It's a '17 390 rr-s with roughly 150 hrs. I'l fill it to the top of the sight glass, ride about 50 miles, then next week when I'm getting ready for the ride it's at the bottom of the sight glass and I top it off again. I've been doing this for a few months and I ride every sunday. I don't see any smoke or leaks anywhere.

[Johnno]

How much do you reckon you add each time in volume?

[Enmerdeur]

If its 150 hours on the same topend I would say the answer is pretty clear. Time for new piston and rings. I do a topend on 4 strokes at least every 100 hours as a rule.

[betadan390]

my 16 390 has been like that from brand new . i find that if you put in 800 ml right from the start it doesnt lose or use any in 10 to 12 hr period,i know it doesnt make any scence but thats what it is. i use motul7100 10w40

[Noppy]

Also check the amount of oil draining from clutch / gearbox side. Sometimes it might flow from engine to gearbox. Don't ask my how I know this