Motorcycle Fuel System Problems Q&A
A motorcycle's fuel system has many components that can experience problems, including injectors and pumps. Sometimes a pressure test is the best way to diagnose problems with a motorcycle's fuel system.
Our resident motorcycle expert John Talley does live Q&As every Friday at 3pm Eastern on our YouTube channel, and in this session, he addresses a fuel injector problem with a Suzuki GSXR 750, as well as a fuel pressure problem with a Yamaha R6.
I have a 2007 GSXR 750, and the secondary injectors aren’t spraying at all, just the first injector to the left is spraying. What causes the injector not to spray?
John Talley: One of two things, either A. it’s not getting enough pressure or B. it could be stopped up. And with these injectors you’re talking about, you can actually clean those and we have a video showing you how to do that with a little kit they have from Motion Pro …
Watch the video above to learn how to clean motorcycle fuel injectors.
When I start my 2011 Yamaha R6, it fires up cold, but after the temperature reaches 135, the RPMs start fluctuating and it starts bouncing around and the engine will die. It misfires at low RPMs. I replaced many parts, including the fuel filter, but the problem is still there. What else should I look for?
John Talley: What I want to focus in on is the fuel filter. Because this really sounds like a fuel-related problem. Just because it has a clean fuel filter doesn’t mean that there isn’t a problem somewhere with the fuel system. What I would be leery of at this point is the actual fuel pressure, so you need to see what the pressure is at just idle, and then pop the throttle a little bit and see if it’ll hold it. You need to find a fuel pressure tester. I’m sure we have them on Partzilla.com, but this may be a one-time use so I would ask around … about a tester that will work on any unit with fuel injection, so that’s the direction I want to point you in. I don’t think we did a video for the R6 but I’m pretty sure we did a pressure test for the GSXR-1000, so if you would, reference that.
Watch the video above to learn how to do a fuel pump pressure test on a Suzuki motorcycle.
Want to see more live repair questions answered? See more motorcycle and ATV repair questions answered here.