2006 Road Glide.

Yesterday I noticed my oil pressure was dropping while I was running at freeway speed. When I accelerated the pressure went back up to about 34lbs but when I let off the throttle the gauge began to drop back down to around 10lbs. I nursed the bike home some 30 miles but I didn't get a check engine light. I checked the oil level. It was down about 1/2 quart so I topped that off. I checked the oil sender unit plug for corrosion. It was ok. Ran the bike this morning and it did the same thing. I went to the dealer and picked up an new sending unit, then to Harbor Freight for an oil pressure gauge that plugs directly into the engine block for a physical pressure check. Came home and pulled the OEM sender unit off and installed the pressure gauge. The hose was about 5 feet long so I wrapped it around the right crash bar then duct taped it to keep it in place so I could read the dial while I rode the bike. I ran it for about 15 miles and it stayed right up there at about 38lbs. When I brought the bike to an idle the pressure came down to about 20lbs were as the gauge on the bike came down to about 10lbs before the current problem began. I brought the bike back home and installed the new sending unit. Had to remove the forward exhaust pipe to get a wrench on the sending unit. Apparently it needs a crows foot wrench and requires about 100 inch pounds of torque to tighten. I didn't have the wrench and a deep socket won't fit on the sender unit because the frame is in the way.
So bottom line here. fluctuating oil pressure was the sender unit gone bad.

 

Theres a way to test the gauge also, I forgot which wire to jump or ground, its in the service manual though. Mine did that a few times and it wasnt my sender or gauge, but the oil pump was going south. I would take the oil filter off and cut the paper open to look for metal particles.