OK, let me see if I can make a long story.... well, long.
Facts:
1998 Road King Classic w/Stage 2 kit and about 65,000 miles.
Started making lifter noise, progressively got worse. Front cylinder leaked oil at base and rear cylinder was leaking at head so time to rebuild the top end.
The lifter issue was weird. Apparently the dealer didn’t install a spacer when they put in the Stage 2 cam and floated back and forth till it messed up one of the lifter roller bearings. Marred the cam pretty good so…
1. New cam
2. New lifters
3. New cam bearings
4. New cylinders (sleeves had lifted a bit)
5. New pistons
6. Heads reworked at dealer
Put it all back together and cranked it up and it runs great…

Until the engine gets good and warm. Then at idle, the oil pressure light would flicker and lifter noise would start to be a bit too much.

Anyone got any ideas why I would be suffering low oil pressure at this point? I took off the oil pump and inspected it. No broken teeth or anything from a bearing needle that might have gotten loose….

I’m going to tear it down again and look, but I would like to have some ideas of what to look for….
Thanks.

 

Could have a perished oil line and its sucking its inner layer into itself when running and warm, you could be losing pressure at the relief valve.

 

Howdy neighbor...I live right outside Memphis. I have a gauge on my EVO and it has virtually no oil pressure at idle...mainly because I have it idled too low because I like the way it sounds...as soon as I touch the throttle the pressure comes right up. The motor doesn't seem to mind...been that way for 15 years. If you adjust the idle up a little, does the light go out?

 

I wander if with the cam floating without haveing its spacer if it could have worn the brass bushing in the cam cover making it loose oil pressure.
By the way I set my idle to about 900 as evos are known for low oil pressure below that.

 

Do you know what the end play is on your cam?

 

I've seen posted many times that evos have low oil pressure at below recommended idle speed. Did a little looking and fueling makes a replacement pump that puts out more psi. Haven't gone that route yet cause cheaper to idle a bit faster.

 

I set mine to about midway between min and max of what the manual says.

 

My oil light flickers when hot, and I have it idling at about 400 rpm. But my lifters do not get noisy. My manual says it is ok if the oil light flickers at idle.

 

First as previously stated check your Idle speed with a tach. Way too many riders have their idle set too low. This can cause engine damage and make the carb hard to tune, idle should be set around 900 RPM's. Secondly you didn't say anything about replacing/checking your oil pump. Metal going through the oil pump will score it and cause oil pressure to drop as the engine warms up and the oil gets thinner and the clearances open up. Did you flush out the oil lines and tank, if not the metal from them could get into the engine and damage the new components. Hope this helps.

 

Check the witches hat screen for being clogged with debris or metal