engine oil use

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David Richard
Posts: 273
Joined: 04 Sep 2017, 20:21

engine oil use

Post by David Richard »

how much engine oil should a 750 use over 500 miles with 20 k all standard but with a 17 teeth front sprocket ,so I never rev past 6 k which is 80 mph
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: engine oil use

Post by Freddy »

Somehow I don't think you're going to like this answer ........

If the oil is new, and a high quality appropriate brand, at 20,000 miles (32,000 kilometers) on the engine, and a conservative rider .... my experience is that oil consumption should be near enough to zero (all engines use some oil).

My engine is now just starting to use a little oil after 85,000 kilometers since being rebuilt. I added 500ml after the recent 2000 kilometer ride. A lot of that was pushing the bike hard. At the mileage of your bike, I wouldn't have needed to add any over that distance. My engine has been flogged (no other word for it) for much of its 85,000 kilometers. For the first 60,000 kilometers after rebuild it basically used zero oil, but them again I change the engine oil every 3000 - 5000 kilometers thereabouts.

With 85,000 kilometers since the top end was rebuilt if I ride it conservatively, with regular oil changes, I wouldn't expect to add any significant amount of oil between changes (maybe just the smallest top up). That's keeping the oil always flush with the 'full' line.

If you're using oil, as I suspect the reason for the question, first thing is to check the cylinder compressions. If you don't have a compression gauge this is about a 10 minute job for a workshop.
David Richard
Posts: 273
Joined: 04 Sep 2017, 20:21

Re: engine oil use

Post by David Richard »

hi thanks for the reply I would ask one more question ,if the valve oil seals have gone hard if oil is leaking back would I expect to see some smoke from the pipes ,the oil has gone down by about 3mm thanks for your time ,david
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: engine oil use

Post by Freddy »

David Richard wrote:hi thanks for the reply I would ask one more question ,if the valve oil seals have gone hard if oil is leaking back would I expect to see some smoke from the pipes ,the oil has gone down by about 3mm thanks for your time ,david
3mm over 500 miles (800 kilometers). Without going down to the garage and measuring the distance between the full and low oil lines, I'd guess they were 15mm apart. So that would mean you'd HAVE to top up about 1 liter ever 4000 kilometers.

That's not great for a bike of your mileage, but it's not a disaster either. Somewhere in between. So where's it going? Down the valve seals? Usually this just results in a bit of smoke at start up from the oil build-up in the cylinder as the oil dribbles slowly down the valve stem after the engine has been turned off.

There was a doctor on a ride I went on one day, and they were telling me they were taught to eliminate the most likely causes of the patients complaint before considering the exotic or rare. Must be standard problem solving technique because that exactly how a mechanic should approach diagnosing a problem.

Excessive oil consumption, if it isn't due to a leak, is most often due to worn bore and rings (or variation on that theme such as seized rings from overheating). A compression test is the best way to evaluate that situation. But a quick dirty method .... there's an oil drain pipe and collector running down the right hand side of the frame and ends near the foot brake. It's a tube with a small container on the end with a plug in it. Is there oil in it? Drain it, ride for a while, and then recheck. If the bores are worn that's where a lot of the oil will end up. Compression leaking past the rings will pressurize the crankcase driving oil up into the air box, and the excess drains into that collector.
David Richard
Posts: 273
Joined: 04 Sep 2017, 20:21

Re: engine oil use

Post by David Richard »

hi thanks I checked the oil res yesterday ,it was dry I will book it in for a compression check and see what turns up ,again thanks
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: engine oil use

Post by Freddy »

David Richard wrote:hi thanks I checked the oil res yesterday ,it was dry I will book it in for a compression check and see what turns up ,again thanks
Let us know the results.

P.S. When I said its a 10 minute job to check the compression I wasn't exaggerating, so don't let em charge you much or try and up sell adds ons like a leak down test. Plugs are easy to get at (just a bit hot getting the middle ones out as the test should be performed with the engine up to temperature). They just have to screws them out, stick in the gauge, open the throttle and spin it over a few times. That's it.
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ZR468
Posts: 170
Joined: 04 Sep 2017, 13:51
Location: Vancouver, BC, Canada

Re: engine oil use

Post by ZR468 »

David, I bought my ZR750 this spring with 21,000 km on it. It sat in a garage for the past 10 years. We recommissioned the bike. The first 1,500 km, the bike went throught 1.5 litre of oil. I have no idea where it went. I was worry. I topped the oil up. But now another 2,500km later, not a drop of oil used. I guess it took an old and unused engine a few kilometres to settle in the rings and seals. Good luck with your ZR, it may work itself out.
Kenny
David Richard
Posts: 273
Joined: 04 Sep 2017, 20:21

Re: engine oil use

Post by David Richard »

thanks again to you both ,I will have it checked out
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: engine oil use

Post by Freddy »

Be aware the 750 engine has a way of 'hiding' some oil every time you do an oil change (well mine does). Drain the oil, fill it back up to the max line level, start the engine and run the bike for a minute or so, then check the oil level.

As expected it will be well below the max line level due you think to the oil yet to drain back into the sump from running the engine. So wait. Ten minutes latter mine will still be well down from the max line. Where has it gone???? I dunno. But I always have to stick quite a bit extra in after initially filling the bike, and then starting it, and waiting quite some time for it to settle.

Before I knew the engine had this trait I once thought I blown thought a liter or two of oil just in a short ride.
David Richard
Posts: 273
Joined: 04 Sep 2017, 20:21

Re: engine oil use

Post by David Richard »

yes thanks I have seen that on a c3 I had years ago this is a d1 ,it was interesting the other post with a engine that's been stood for a while .I am over the winter have a friend who knows what he is doing replace the cam guide and tensioners and seals the engine has some camchain noise at idle I will ask him to check the compression its worth it to me thanks again david
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