Low oil pressure, check the pump and relief?

The oil pump is blocked by the clutch?
Steve

pg70 of the FSM lists the following steps under oil pump removal

Drain Oil
Remove Mufflers
Remove Clutch
Remove Pan
Remove Bolts and Oil Pump

I will take a crack at this tonight.
At first glance it looked like the pump was held in place by bolts that came from the under the clutch cover.

It might be possible to remove it without taking off the clutch basket. If not, you can press the brake pedal to lock the engine from turning and take off the nut. I'm almost home so I'll check back this afternoon. Good luck.
Steve

That does suck....... the basket will have to come off if you decide to tear it apart (can't get to the screws)........ might be able to use the brake to hold things but might be tough holding it when re torguing to 100 lbs ......( I bought a EBC clutch holder tool) but will need a hand held impact for the screws and a elect or air impact for the hub nut......instead maybe a 30mm socket for the basket nut and a big breaker bar but that's iffy from what I've read..... then they say to replace the 2 thrust washers and the 30mm nut, clutch housing gasket too....... maybe even the clutch springs while you're in there ( I like that idea)

Will maybe tear up the screws holding the pump so might have to replace them 10mm bolt shouldn't be a problem and you'll need some blue loctite and to re stake em with a good punch. I removed my pump to get to the starter clutch but didn't tear into it hoping with the fairly low miles (30,000) I have and always changing out the oil kept it in good shape. Up to you to decide on this one.

In the interest of measuring the effect of a missing o-ring, I think I'm going to leave the pump alone for now.
I know full well this means extra work (mufflers, drain, pan, etc) if the missing o-ring isn't the issue.

Maybe I'll change my mind by tonight.

Go to OR/AZ etc and get a O ring if you don't have one. Chances are with one you will have enough oil pressure.
Steve

Solved, sort of. I replaced the o-rings. I put the flat side of the ring against the block, they seemed to stay in their holes that way.
At cold idle I had super mega pressure. Enough that I could peg the meter at 75 psi at 3.5k rpm. I believe the pressure relief vavle is working. After 2min the idle was 32 psi, 4min 26psi, 6min 22 psi.

I then rode for 45min with a mix of 60mph hwy and 25mph stop/go.
At the end of the ride I was idling at 4-5 psi with a 4k rpm psi of 22.
The oil light never come on during any part of the testing (except for pre-ignition of course).

What I've learned since is that my cheap Ashcroft 100 psi gauge is grade B (ASME B40.1).
Which means it's accuracy in the bottom 25% is +/- 3% of full scale. Optimistically my 4-5psi idle could be as high as 7-8.
And my 4k hot pressure could be as high as 25.

I think I'm ok with this, and will make the oil pump a winter project unless the oil light starts coming on again.
Now I can get back to tuning.

Glad this worked out ...... I had my motor upside down both times when I replaced the 3 o rings and I can see where they would be tough to keep in place with the motor still in the bike.

A little grease will hold them too. A major part of the pressure difference is the multi weight oil.
Steve
Steve

Just checked my 750; 43k miles and was 25 psi at idle to 45 psi at 4k. This was on a cold motor with 20/50 oil.

I get similar numbers.
KZ650, 18k miles, 25 psi idle and 75 psi at 4k, cold motor, 15W40

We are the same at the idle figure, but you are 30 psi higher at 4k. This is my question of how much the pressure relief spring affects rpm pressure. Too high oil pressure can cause problems too, as well as using power.

I'd be interested in what other figures are coming up. Shame I didn't test my 550 before splitting it this week