oil pressure value on KZ1100

I'm sure this 82 KZ1100 is running way too hot and this week I will get a remote thermometer and have ordered a low value oil pressure gauge to test it all - but in the mean time I am trying to learn all about the oil system. in "preparation".

I was very surprised to read in the manual that the pressure is supposed to be ONLY 2.8 lbs/sq in !!! Its hardly measurable - hence ordering a low pressure gauge.

So - Why/how behind low pressure engines? Does this mean we have to watch these pressures constantly given a tiny drop in pressure can be catastrophic?

I guess I should expect to find low pressure as its getting so hot - ?? - and given low pressure - Am I to assume it is the oil pump ? (yes?) - I also assume we can fix these oil pumps? - In which case - What is it that wears on these pumps? ( can't see new ones for sale on partzilla etc ?? - but may be there is a supplier like everything these days - if so can you help please?)

Finally - When I switched to synthetic recently - an oil leak appeared at top front left in front of the head bolt (worn or damaged stud O ring no doubt - but I'm not wanting to do the head until winter (mid summer here in Oz right now) - SO given that leak - will an oil pressure test of such a low pressure system be of any use anyway? (I am hoping you will say - fill her back up with mineral oil again instead of synthetic to do a pressure test? In which case - will 15W/30 suffice or thicker (20W/50 ??)

Thank you in advance for your valuable experience thank you.

Greg

1. Don't use fully synthetic oil in these engines UNLESS it is specially formulated for roller bearing cranks such as Rock OIL TRM 20/60.
Silkolene super 4 Semi synth 10/40 etc is ideal.

2. These engines run high volume, low pressure oiling systems because of the roller crank and a near zero reading when hot is normal.

3. The oil pumps rarely give trouble, especially the 1000 onwards ( the early 900's had some air lock troubles which was easily fixed and is not an issue on your engine)
I'd check that the oil strainer is not partially blocked before stripping the pump, although there is very little to go wrong in the pump and all you can do is tighten up the side clearance with a thinner gasket or some light lapping of the body.

Thank you very much for this advice. I do not even know what roller bearing cranks are (I'll got do my research tks)

SO oils - I doubt the oils you describe are in Oz at all - so would you recommend a natural oil grade for hot weather please?

Also - what is the difference between synthetic and non synthetic - as far as these roller bearing cranks are concerned? (what is it natual oil has that these cranks need>)

It does explain why the leak appeared only after I put synthetic in . I sure hope it goes when I replace it

Fully synth is too slippery for roller cranks and causes the rollers to slip and spin rather than roll which causes excessive wear and unless formulated for wet clutches will cause clutch slip as well.
The fully synth also runs very thin when hot hence the increase in oil leaks.
I'm in the UK so can only recommend the oils i have used here.
Some of these are -
Silkolene/Fuchs super four 10/40 semi.
Castrol GTX 10/40.
Rock oil TRM 20/60 Roller crank formulated fully synth ( in my tuned engines).
Obviously you will probably run a thicker grade to compensate for the warmer average temps so maybe 20/50 grades will be more suited.

What makes you think it's running hot? The oil pumps on the 1100's ars bulletproof and yes they run really low pressures. Don't worry about it, it's about volume not pressure. FYI all roller bearing cranks run low pressure pumps. That includes most big bore single cylinders such as the Honda XR600, XR650L. Those are very durable engines.

Thank you for all the replies and education - very useful. My thermometer arrived and - no its not running hot (145 deg C at exhaust header) and cool everywhere else according to this lovely temp chart found on KZR see - kzrider.com/forum/2-engine/459413-kz1000-running-way-too-hot (halfway down thread)

Just feels b... hot as its the first big bore air cooled bike I've owned. Every other one has been modern water cooler sports or similar like CBR1000RR or Monster 600 etc.

Oil pressure gauge not arrived yet to test pressure.

So now its not hot - I'm now back to original issue that started all this - which is after I have ridden for more that 20 mins - engine starts to blat blat out the pipe as I ride along at normal speeds (70 - 100k) and more and more as I slow - none of which happens when first running and cool (but now we know temp isnt the issue).

I've replaced the pulsing coils, the coils, the igniter. New plugs.

All that's left is the carbs - but I set the butterflies by hand with carbs off the bike using physical spacer and checked the plugs for rich/lean colour and adjusted where needed. Now what?

ALL ideas welcome tks. (I'll post this all on a new thread too )

Tks