Lost oil pressure

Hey guys. New here. And new to old Kawasakis as well. Picked up a 1976 kz900 with 1000 cylinders. Runs great. Love the bike. Other day I'm running it through the gears, at about 8000 rpm getting ready to shift the oil light came on and it stopped pulling hard. I shut it down right away and rolled home in neutral. I started it one more time (yes I checked oil level and its full) and it runs but oil light still on so I shut it off right away.

I'm guessing oil pump went out, and the engine started getting too hot due to a lot of friction because of lack of oil. So my question is: what does it sound like to you guys, and if I'm right about oil pump, what are the chances there is internal engine damage? What would be hurt first? Cam Bearings? Piston rings? Is there a good aftermarket oil pump?

Thanks in advance. Great website. I've already learned a lot.

Might be sludge built up on the strainer. Try The Old Kaw Man on line. He has lots of oil pumps. I took two and made one. There are thinner gaskets as well to raise the oil pressure. First pull the pan and see if it is clogged. These engines are pretty tough. As ling as you shut it down right away and use good quality oil, you shouldn't have caused damage. The crank and transmission gets oil first, then the cams. The top end gets destroyed first. Guess how I know.





You'll have to remove the pipes to get to it and lay it on it's side on a block of wood resting on the alternator. If you take out all the bolts and bop it with a rubber mallet, you may be able to reuse the gasket. I use High Temp Copper silicon Let us know what you find and pics too.
Steve

Check your oil pressure switch also. Could have a piece of crud or silicon stuck in that also. I would drop the pan and look at the pump. Ive had bad pumps. I would doubt you did any motor damage if the motor still sounded good when you restarted it.

Oil pumps tend to last quite well, they tend to be quite well lubricated ... I'd agree test the switch first, is it oil pressure or level? Then check the pump strainer gauze in the sump, finally the O ring inside the cranckase that the pump connects to.

These motors run low pressure on a roller bearing crank - unlike the smaller fours with high pressure shell bearing cranks, a zed 9 series will tolerate temporary oil starvation much better imo. Think of all the headbangers wheelying these, or sliding them down the road through the years....

Wow, now that's bad. :ohmy:
The oil pump gears are hardened and very tough. What goes wrong with them is small fragments of metal can score the aluminum faceings. To repair one of these, you can take #600 wet/dry paper on a sheet of glass and smooth out the wear marks. That's what I did plus matched the tightest gears I had. Cold start up it's at 20+ PSI then goes down to 3-4 PSI when hot. A lot of it has to do with the 20/50 oil I use. As the oil gets hot, it gets thinner.
Steve

Thanks guys. I will look into it and let you all know what I find. I think the switch is fine and functioning as it should because the engine seemed to "flatten" out, instead of pulling hard like it should have been. Meaning there was a problem and the idiot light came on right when that problem happened.

Wont have time for a week or two to look into it but as soon as I do Ill report my findings.

Thanks for the advice!

Finally found some time to look into it. Took pan off and pump out. There is some scoring inside the pump where the gears spin. O ring is ok. And found a small piece of metal in the pan....Ill get a picture. Trying to figure out where the metal came from.....

Screen was clean on pump.