Oil Pressure

[Fatman]

My engine is running between 10 pounds at idle and 35 pounds at 4000 rpms hot, is this good or bad??????????

[TopCatGr58]

Hey there Fatman,

Your values sound a little low, the relief valve is set at 70 lbs, a fellow Xsive posted his is 60 cold, and 42 at cruising speed/rpm, and the manual states around 42 for cruising rpm.

However, it might also depend on what type of oil, a lower viscosity range might show lower pressures than the higher range at the same temps!?!?
T.C.

Are you a fan of Jethro Tull by any chance??

[Dragon Tamer]

Fatman,
What TC said, sounds just a little low. What kind of oil and what viscosity are you running?
The Dragon used to run about 55 to 57 cold and 40 to 45 warm but since I have been using the Sheaffer 20/50 synthetic blend it now runs about 25 at an idle and 45 at cruise cold and idles at about 35-40 and holds a steady 55 at cruise warm.

[Fatman]

I just changed the oil, had been running Castrol 20w50 motorcycle oil, this time I went to Lucas Synthetic, 20w50. Still the same pressures. Cold 45 at idle, 70 at 4000 rpms, hot barely showing any pressure (5 to 7) to 35lbs at 4000 rpms........ I am using a automotve type mechanical gauge, would that make a difference?

Fatman

[79XS11F]

Where are you taking the pressure reading?
Rob

[Fatman]

Rob,

I replaced the Oil pressure sending unit with the mechanical gauge.


Fatman

[79XS11F]

OK ... there or at the side access pipe that goes to the head supply tube is where to do it. If your getting repeated low pressure readings and everything else is normal like oil level, on main stand, right type of oil etc ... you "may" want to consider pulling the oil pump and check it out.
Rob

[Fatman]

Rob,

Been a automotive mechanic all my life and have built cars and trucks for a livin', bikes are very new to me. Could the oil pump just need replacing or is the problem deeper? Cars having low oil pressure normally mean loose bearings, ie rods, mains, and camshaft............ am I close or way off base??????

Fatman

[79XS11F]

Everything you already know about engines from your auto background will apply to this engine. Bike engines are of course different in several ways but the basics still apply.
The low oil pressure issue could be ether the pump or the bearings or could even be that you will not get that 42 PSI you want until a certain RPM is reached. I can't even find the spec in my factory manual.
Rob

[boyat68]

There is a page 7-13 in the manual that gives an oil flow diagram and the following information.

Relief valve opening 4.8 kg/cm squared (70 psi)
Cruising speed oil pressure (at operating temperature)) over 3 kg/cm squared (42 psi)
Oil warning light Activating pressure 0.3 kg/cm squared (4.2 psi)

Cruising oil temperature 102 degrees centigrade at 88 km/h (216 degrees F at 55 mph0

[John]

I have an OP gauge on my bagger, and the pressures are around 60 psi at all rpm when cold, and when warm, I have 60 at speed, and about 5-10 at idle.

[Fatman]

I installed a SW gauge in place of the local parts store cheapy, I am getting about 5-8 lbs at idle and 45-55 at 4000 - 4500 rpms after she warms up. I also purchased some exhaust wrap, and a oil cooler, figure every little bit helps. I really do enjoy the bike, especially the power....................

Fatman