R1100 Fuel Pressure Regulator Replacement - Questions

[Jim Moore]

I spent yesterday afternoon and evening cursing softly to myself as I rode 600 miles home with a leaking FPR. It's a minor leak, just enough for me to ponder whether the bike would burst into flames every time I stopped. Luckily it was raining the entire time so the fuel was immediately washed away by the deluge.

But now I gotta pull the FPR and rebuild or replace it. The stock answer is to lift the rear subframe and get at it that way, but I remember hearing it can be done with the subframe in place. Has anyone tried that technique?

Also, what am I dealing with here? If a line is cracked I have to replace the spider, but I assume I can use the old regulator with some new o-rings? If it's leaking at the regulator itself I just replace the o-rings?

 

[JimVonBaden]

The whole thing can be removed by loosening the airbox and nearby parts and wrangling it out. It is a pain, but doable. Yes, you can reuse the regulator.

 

[south east okie]

Jim , keep us posted on this goes, please.

 

[Jim Moore]

OK, got that one done. The issue was this. The hard plastic line on the left side comes through a slot in the airbox. It’s protected by a small rubber grommet. My grommet had worked itself out of position so the line was rubbing against the airbox. Eventually it rubbed a small hole in the line, causing the leak.

A new spider and set of grommets and o-rings cost me about $200. I re-used the actual FPR, although I replaced the internal o-rings. It was a pretty simple repair. The trickiest part of the entire evolution was getting the big circlip that holds the FPR back into place. That was a PITA.

I decided to lift the rear subframe. By the time you remove everything else you need to remove lifting the subframe is a matter of four bolts and a few connectors. And it makes the job a snap. YMMV.

I really question the wisdom of BMW using hard plastic lines in this application. Rubber fuel lines would be a lot easier to work with. Metal lines would be harder to work with, but would be much stronger. Hard plastic lines combine “brittle” and “hard to work with” in a manner only BMW could conceive.