What is acceptable oil consumption?

I’ve noticed lately that I’m using about 1/2 Litre of oil every 500 miles in my 900 Supersport. It has always used a little oil, especially when pushed hard, but what is deemed to be acceptable consumption? The engine has 34k on the clock and still performs well enough to see 140 on occasions (trackdays of course, officer!), so no performance issues but I’m tempted to do a top end rebuild this winter. Any comments would be appreciated. :question:

Seems a bit excessive Chris, my M900Sie never uses a drop, probably needs a look at the heads at least?

Hi Chris,
500 miles to the pint is Blo*dy good for a motor with 34K on it in my book.
Providing that the valve stems/guides, pistons and bores are in good shape?
New rings, valve seals, decoke and lap the valves should probably restore the crispness to the motor, also cutting the oil consumption to almost nill.
I’ve just got back from the TT and my 851/916 is due an oil change, in almost 2000 miles including a day on the Dyno there’s no noticeable differece in the oil level.
But if it had used a pint I’d have been well happy and this motors only covered around 7500 miles, since I nailed it together!

Steve R

Edit/added later,
Following on from your similar post in ‘Another Place’…
Chris remember that if you go down the route of Hi comp’, Big Bore and FCR’s, you’ll need to refresh/rebuild the bottomend as well.
One of the 1st things my Father taught me about engines was that tuning/increasing the power output on an old motor without doing the bottomend as well, will shortly result in the bottomend letting go.

I was thinking that while I have the engine apart anyway I might get it bored out to 944cc, have the heads gas flowed and maybe fit a set of FCR Keihin carbs. The latter mod in particular is said to release a fair amount more power and improve the rideability of the bike at the same time. Anyone have experience of this conversion and is it worth the considerable outlay of cash?

I know that the commonsense answer is to sell it and buy a 916/996/998 etc. but this bike was bought for me by my wife as a 40th birthday present and I could never sell it. Besides, in the ‘real world’ I have never needed anything more powerful or faster. It would be nice to give rice burners a scare or two on track days though and I like the idea of having a ‘sleeper’ bike.