2006 RXP Compression Reading analysis

[Sportster-2001-951C-Stock]

Hi dennis that is exactly what i was talking about. I believe I found the right spot. is it the little red screw in pic?

Also as you guys have stated, yes i want to narrow it down and find the cause of the oil pressure signal before worrying about compression. I am bringing the ski to a car shop tomorrow to borrow the oil pressure tester. I will see what I find then. Also how do I check the oil screens youve mentioned? Are you talking about the oil filter or is there something else?

Assuming there's enough room to leave a gauge mounted on the head, you could just buy an 100psi gauge and whatever fittings necessary, maybe 1/8" pipethread or metric? I'm not sure. Screw the gauge right into the head and leave it there permanently for future use?

The reason I'm suggesting this is it's always nice to have a way to monitor the engine OP occasionally to get an idea if something's a-okay or not, and oil pressure ordinarily drops considerably as the engine and oil heats up, which can't be simulated on the trailer. You might have a good 50psi idling cold and that could drop to 5psi hot, hopefully not less than 10~15psi, general rule of thumb is 10psi for every 1000rpm hot oil.

I would of course prefer a lower psi gauge because the accuracy would be better at lower hot idle pressures but I don't know what maximum OP to anticipate with this particular motor. Say for instance normal OP at idle with hot oil is 50psi, and at WOT is 150psi, the 100psi gauge would be inappropriate. Typically, I see about 60psi cold oil max pressure and idle around 15psi hot, that's usually enough for a healthy engine.

So, 100psi gauge would be too large in that case, an 60 or 80psi gauge will give a better read at hot idle conditions.

Gauge needle should not pulsate up and down as RPM is held steady, a pulsating needle indicates a leak emerges at a certain crank position.

 

[kevmanetti]

I would of course prefer a lower psi gauge because the accuracy would be better at lower hot idle pressures but I don't know what maximum OP to anticipate with this particular motor. Say for instance normal OP at idle with hot oil is 50psi, and at WOT is 150psi, the 100psi gauge would be inappropriate. Typically, I see about 60psi cold oil max pressure and idle around 15psi hot, that's usually enough for a healthy engine.

So, 100psi gauge would be too large in that case, an 60 or 80psi gauge will give a better read at hot idle conditions.

Do I do this test with the hose hooked up or dry, I will not have access to the lake for sometime. As I am going to the car shop not sure on the hose either. I have the manual it gives me the proper oil pressures.
However the values are different then you suggest.

The manual says that some sensors will trigger the warning with a psi lower then 32psi. So it seems as though the 15psi range would be alarmingly low?. I am all new to this so I maybe wrong.

 

[Sportster-2001-951C-Stock]

Do I do this test with the hose hooked up or dry, I will not have access to the lake for sometime. As I am going to the car shop not sure on the hose either. I have the manual it gives me the proper oil pressures.
However the values are different then you suggest.

The manual says that some sensors will trigger the warning with a psi lower then 32psi. So it seems as though the 15psi range would be alarmingly low?. I am all new to this so I maybe wrong.

I'm speaking in general for typical four stroke engine rule of thumb, your mileage may vary with adaptations. I already stated I don't know the details of this particular model.

Stick with your spec pressures, it's good you have specifics to work by so stick with them. Oil pressure is inversely correlated with oil heat though, so expect cold engine pressure to be higher than normal operating temp pressure.

So if you have the pressure specs, you can choose a gauge to put you in the range. (a 10,000psi gauge is inappropriate)

I guess you can start the ski and run it for 10seconds without water, this is long enough to get a cold engine pressure reading. A hot pressure reading is after about 20 minutes of running under load, that can't be simulated out of water.

Expect a lower pressure under normal operating conditions. A cold test won't tell you what the hot oil pressure will be, which is why I suggested installing a permanent gauge.

I don't know how to simplify any more than that.

 

[Dennis]

I can't exactly tell from that picture but it appears to be the correct screw. It will be the only allen screw in that area.

The service manual shows a better picture of it.