angliamotorsport
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| posted on 18/9/12 at 06:25 AM |
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oil pressure on zx10r
Was at Snetterton at the weekend and engine was going like a trail but on lap 7 the oil pressure just went down slowly to single figures and had I not
kept blipping the throttle would have gone altogether.
At tickover it is shoung from cold about 46psi, when warmed up and pulling 12500revs it is showing 88psi.
Any ideas why the pressure should drop like it did after around 7 laps.
Water temp at the 12500revs was about 77.
I'm baffled, no pun intended.
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angliamotorsport
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| posted on 18/9/12 at 06:26 AM |
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Sorry for spelling mistakes but I'm short on time trying to get to work
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cliftyhanger
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| posted on 18/9/12 at 06:45 AM |
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Normally the oil is escaping from where it is needed too easily.
That means engine wear, oil over-thin or pressure relief valve leaky. Or a dodgy pressure gauge, but this sounds unlikely here.
I have no knowledge of bike engines at all. But my first port of call would be to ask how suitable the oil was, cars on track push the oil way beyond
what is normally experienced.
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adithorp
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| posted on 18/9/12 at 08:43 AM |
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Oil pressure at idle on a bike engine is very low when hot and there's a big variation between hot and cold pressure at revs as well. My R1 is
5-7psi at hot idle and varies between 60-90+psi (hot/cold) at revs.
When you say it dropped to single figures, what revs was that at?
Did the presure return when cold? Was this drop different from previous use?
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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PAUL FISHER
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| posted on 18/9/12 at 09:06 AM |
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I was suprised how low the oil pressure dropped on tickover my 2007 ZX10r, it would be down as low as 5 psi when hot, I had separate oil pressure and
oil temperature gauges fitted, but the oil pressure light on the dash would not come on.
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BobM
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| posted on 18/9/12 at 01:06 PM |
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My 06/07 ZX10R runs similar oil pressures and they do tend to drop when hot. By the end of a race my oil temp's usually getting on between
110-120 degrees and at that temp idle pressure will often drop to 2psi or so. I'm running Silkolene 15/50 synthetic oil too.
I used to see 5-7psi on my Busa, Kawasaki's seem to run a slightly lower pressure.
Not very Locost but very BEC 
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motorcycle_mayhem
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| posted on 18/9/12 at 02:38 PM |
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When hot, getting any number from the transducer is sometimes difficult. When cold (and don't do this at home) and revving a tad, I'll see
3 figures....
Any circuit work will see the gauge plummet. Four or five laps of Castle Combe (and Snetterton isn't far off that abuse) will see the temp.
gauge rocket and the oil pressure gauge tumble.
Your bike engine will let you know if it's unhappy with the pressure, very, very quickly. Yours must be happy. It isn't a grey area.
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angliamotorsport
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| posted on 18/9/12 at 03:04 PM |
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Thanks guys, it would seem then that very low pressure is normal when the oil is hot.
Having said that, on Sunday when I started the engine, after sitting all night in the paddock with a cover over the car, the pressure went up to 46psi
at cold tickover and produced the same results pressure wise after blatting round the track, ie high pressure and then dropping progressively while
returning to the paddock to park. When stationary it was showing 1-2psi at tickover, but no hot metal or burning smells or smoke.
To be fair to the engine it was being asked to work quite hard, so I'm not really sure what to think except that it sounded typically
Kawasaki.
If anyone has any more thoughts??
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angliamotorsport
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| posted on 18/9/12 at 03:11 PM |
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I agree entirely Motorcycle Mayhem, although I have not done Castle Combe, Snetterton does give the engine a good blow and when you are sitting
looking at the shift lights blinking like a Christmas tree on steroids with a fair bit of the main straight left, it makes you think.
I had a zx9r drop it's oil pickup and within the blink of an eye the shells had gone.
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angliamotorsport
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| posted on 18/9/12 at 04:17 PM |
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Just had another thought, would an oil cooler with stat help by keeping the oil cool and therfore possibly keeping the pressure up.
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cliftyhanger
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| posted on 18/9/12 at 05:35 PM |
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Oil coolers generally help.
As above, not a bike person, but there can be nothing wrong with trying to keep the oil temp a bit lower. Less chance of "issues"
On my car I had a similar incident at goodwood last year. Fresh engine, but oil pressure was down to about 20psi on the straight (5000+rpm) Cost me a
set of bearings, though once cooled the pressure was much improved.
Now have a cooler for the oil, will be tested at goodwood again in a few weeks. Also have an oil temp worry gauge to fit.
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