I have a 2009 StreetGlide with a 103ci on it. A couple of months ago I noticed my oil pressure gauge acting funny. Sitting in neutral and revving the bike the oil pressure goes up and down as normal, and cruising down the road it's steady as normal, but when I get on it and ride under acceleration (slow or fast) the oil pressure consistently goes down until about midways through acceleration and then it goes back up to normal. Almost as if the oil was pushed to the back of the pan on acceleration away from the sump, but as I understand the baffle and sump design that's considered to be impossible. Before making any suggestions here is a list of things I've done and tried.

New SE billet cam plate and HO oil pump assy.
Oil change with new HD filter and Mobil 1 V-twin that I've run since I bought the bike
New sending unit
Manual oil pressure gauge installed directly at the sending unit port



The problem was happening before the first part was changed.

All my local sources and mechanics are stumped. I've taken all the possibility of electrical out of the equation with the manual gauge so it's got to be mechanical.

I've seen experiences with this from searching and researching, but it always turned out to be a gauge, sending unit, or pressure relief valve. And I've never found an occurrance of it happening under acceleration like this one.

It all of a sudden started happening so it's a new problem. I'm running out of ideas. Any help would def be appreciated.

And NO it's not making any abnormal "no oil pressure" noises.

Thanks in advance.

 

It's the pressure relief valve. As it breaks under a little more oil flow. It's set 35. Idle pressure is controlled simply by proper oil thickness and pump design. Then as rpm gets it to around 35 by more volume, as it gets to over 35, it releases. Just a spring. All you really need is a light. Anything else is annoying unless you had a real controlled and dampened gage system like most cars to hid this silly fluctuation you see and worry about.

Harleys do not need a lot of pressure since the oil does not have far to go nor is there many areas that restrict flow and induce pressure. Remember, the amount of flow is determined by pump size and rpm. If you restricted it, pressure rises but actual flow after the restriction is reduced. Most do not understand this.

In a car motor, you need the pressure to get to the end of the line. And as shell bearings wear, you loose pressure and near the end, bearings starve. Harleys really do not work like that.

Idle oil is actually designed low so oil injectors which are piston coolers do not work at idle. They themself have relief springs set to release at 18 or so. That way you do not cook the oil at idle when no air is flowing by.

Just my opinion of course.

 

I would say the same thing but that's why I changed the original cam plate for doing it with an SE billet cam plate and SE HO oil pump. What's the chances of the old plate and the brand new cam plate doing the same thing?

 

^thats what I was thinking, but I would never tear into a twin cam, cam chest again with our putting a baisley spring in it. You can add one with out pulling the cam plate. The stock spring is like a ball point pen, just waiting to fail and the SE is the same. I'm not saying it will solve the problem but if your doing the work it's cheap enough to try.

 

If I have to go back into it I may try that. Here's where I slightly disagree with you. The pressure relief valve spring is what determines the bleedoff point ie. what the max pressure is and where the operating pressure is so logic would tell me that the spring in the standard and SE cam plate can't be the same because the operating pressure with the SE pump and cam plate is way more and higher than the standard.

 

All I can say is side by side they look the same. The difference with the SE pump is it will bleed off more oil. But it shouldn't be doing what is going on with yours, their very well could be something else bleeding off the oil in your motor.One thing I noticed when having different springs in one of those fancy air testers(for cam plates) is once they open they don't close as easily. In other words it's far from perfect set up.

 

I would say the same thing but that's why I changed the original cam plate for doing it with an SE billet cam plate and SE HO oil pump. What's the chances of the old plate and the brand new cam plate doing the same thing?

 

One other thing is the Piston oiler's come to mind. They open up when they get more psi. There failure is to just run all the time but u have a strange thing going on so never know. Problem with that one is jugs have to come off just to get at them. I have the S&S oiler's in mine.

 

I totally believe you. This all makes no sense as to what should be happening. And this was a problem that just surfaced after working perfectly for 6-7000 miles.

 

Cmon guys. Is there noone that has any ideas other than the obvious that I've already tried? Manual gauge, pressure relief spring, cam plate, etc.?