Oil consume is normal?

Around 600km and 2-3dl oil, what do you think?

what is normal?

Too much.  600km is only about 3 tank fulls.  Over that much distance, it shouldn't be necessary to add any oil to the engine.

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Too much.  600km is only about 3 tank fulls.  Over that much distance, it shouldn't be necessary to add any oil to the engine.

Agreed, this is only 375mls

My bike has been burning .5L per 500 miles for years now. Maybe 30K miles like that with no change. Not normal but manageable.

These bikes were designed to have their oil changed every 5000km (3000 miles). That implies that it should be able to go that distance without any significant oil loss. Later models were designed to go twice that.

It's reasonable to say that a 'normal' 40+ year old bike will consume more oil - but it does sound like yours is using a fair bit.

Check your compression and compare with the service manual, then check it wet. If your compression is good, it's likely a leak somewhere. If it's low and stays low with added oil, changing your valve stem seals will likely solve some or all of the problem. If it improves greatly with added oil, it's likely rings.

Thank you !

I overhaul the borr comepltky With New pistons and replace the valve seals 4 years ago…

I need to do new measurments Next season!

The first year and two I had problem With the carbs, it cannot be that there is built up to much unburn gases inside the top? or something ?

 

Is there a significant amount of oil in the airbox ? a partially blocked breather will cause excessive crankcase pressure which can push oil past the rings or up the breather tube into the airbox ?

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Is there a significant amount of oil in the airbox ? a partially blocked breather will cause excessive crankcase pressure which can push oil past the rings or up the breather tube into the airbox ?

I can just take off the cover and look inside for oil?

That is too much oil burned on a "new" motor, only 600km in 4 years... would seem you were idling a lot trying to figure out carbs. Could have glazed the bores, 810cc on a 750 leaves the liners very thin, so you should not be idling without a fan running even if you running a oil cooler.

I would do a compression check, then a cylinder leak down if you have the proper equipment.

Is it smoking at all?

5700km since start up.

600km was my last weekend trip, lets say between 1-2,5dl.

Is there a problem to fill oil almost to max indication.

wrote:

5700km since start up.

600km was my last weekend trip, lets say between 1-2,5dl.

Is there a problem to fill oil almost to max indication.

1 dl = 100 ml = 0,100 Liter !!!
100 ml up to 250 ml consumption of oil is a vage supposition! Your driving style is the key! No problem to fill to the max. indication.
Did you renew the valve stem seals?