I've read evey thread on this site relating to oil pressure issues and I'm still at a loss as to the problem.

Bascially the oil light stays lit at idle. I have had my '96 roadking for about 2 months. It's my second road king the first was a FLHR (never missed a beat) and this is a FLHRI with 29000 mile on the clock. First the petrol pump packed in stranding me 100 mile away from home and now this - I'm starting to think this bike is cursed...

About a week ago the oil light came on while I was riding the bike, luckily close to home - started making ALOT of noise form the top-end - so I took the bike into the workshop and have cleaned out the oil lines and mesh filter - place on a new oil filter and new oil - still have the the same problem. Even stripped the top end down - everything looks fine with the valves and tappets - plenty of oil up there - engine turns over fine but the oil light stays lit...

I guess the next move would be to take the oil pump off and give it a clean? What a pain in the a*se - I just want to ride my F ing bike....

Any other ideas?

Cheers Grant

 

Simple stuff first...
Put a direct reading gage on the engine and find out what the oil pressure is...

 

Before you do that make sure the bike is idling around 950-1,000 RPM's/ A lot of the time the oil light come on because the owners want that slow "lumpy" idle. What are you running for oil? If you have synthetic , try convential oil. Lastly remove the oil pressure sending unit and flush out the galley feeding it and you might also consider replacing the sending unit. Hope this helps.

 

Yeah, find out what it really is. If the light was on but everything else was normal, that would be different. The funny noises combined with the oil pressure light is a bit worrying and more indicative of really not having adequate pressure. Cleaning the oil pump won't fix it if that's the problem. New seals, at a minimum, and really, a new pump would be more in line. It sounds like a piece of trash went through it and took out the pump. Did they find anything in the screen? In 80K miles, I've never found anything there. An Evo should have nothing in that tappet screen, which was there to catch clutch plate material mostly, from when the primary shared the same oil supply with the engine.

Also, has your inner cam bearing ever been replaced?

 

Assuming you've read a healthy portion of those threads, you found one thing in common to all - a new oil pump did not permanantly fix the problem for any one them... right or wrong?

The first moving part(s) oil goes to in any pressure system is generally the culprit of low oil pressure, especially at lower rpms and that applies to car engines as well. With that, the first place oil can loose it's pressure on these is the tappet guides. Oil is pressured to the bores for the lifters where it goes thru the lifters and up to the rockers via the pushrods. Any leakage between the lifter bodies and their respective bores is immediately sensed at the oil switch. And often as not, if the bores/lifters aren't totally compromised, single weight oil will hold pressure at higher temps/lower rpms than multi-weight.

 

Sounds like the oil pump going out. I'd take care of it pretty fast before the low pressure damages your engine.

 

I have gauge on my 84...pretty close to 0 at idle when it gets to operating temp...been that way for fifteen years. What kind of oil are you running? You can also shim the pressure spring in the pump with some washers to get the pressure up...I would definitely try that first... because if you really have a problem it is not likely to be the pump...it will be a tappet bore or rocker arm...something with too much clearance. Good Luck

 

Are you sure you have oil flow? Did you look into the tank while the engine was running and see oil returning to the tank?

Possibly a piece of crap in the oil tank that is blocking the oil outlet nipple.

 

I have been having a similar problem with my 97 FLHTC.
First verify the problem using a mech. gauge,at normal operating temp at 1050rpm.
It seems you have already changed the oil and filter,checked the tappet screen, replaced and cleaned out all the lines.
What is your oil pressure at 2000rmps.?(manual =12/30psi.)
If you have that pressure the oil pump relief valve could be stuck open dumping oil to the crankcase.
I also opened the oil pump cover ,replaced the drive gears and checked for debris with a magnet.
As someone mentioned the pump make volume,the resistance to the pump makes pressure (blocks/lifters)
My bike ran 25 cold ,12 at 2500rpm and -0- hot.
I most likely need blocks but I found a temporary solution,I added 2/3 quart of the Lucas Oil Stablizer in place of the Moble 1 15-50 I use.
At startup I get 35psi,20 at 2500 and 5 at Idle on an 85 degree day.

 

Thanks for all the response guys - very helpful. To answer some questions:

I'm running semi-synthetic 10w40 oil, not harley specific by not fully synthetic either and has always run fine in my harleys to date.

I haven't checked whether oil is returning to the oil tank - will do that.

I haven't checked the pressure at idle either as I don't possess a gauge - maybe I need to invest in one.

I think I will check the pressure sringto the pump - shim it as suggested and possibly change to a single weight oil as also suggested.

How difficult is it to check clearance on the lifters and blocks? Sounds like this may be the problem....

Thanks again...will keep you posted.

G.