F4i Burst Fuel Line
 

Hello! I had originally started a thread about my F4i no start issue, thinking it may have been a no-spark situation, but signs are now pointing to a different problem, so I decided to start a new thread.

The long and short: I came back from a very long road trip, no starting issues. I did lowside the bike, with no apparent damage besides scratching up the plastics. When I got home I ordered new fairings and replaced them. At this point, the bike has been sitting for three weeks. When I go to start it (kickstand up, in neutral, kill-switch set to run, BAS upright, fuel pumping IS priming) the engine cranks, and I can feel pressure at the exhaust, BUT the sound of the cranking is different, slightly higher pitched (hard to describe).

With all of the above, I assumed it was a spark issue. But when I got the tank off, I was getting spark at all four plugs. I also inspected the wiring harness, found no corrosion, no pinched cables, etc. Now, here's where the fun part begins. I've got the tank lifted to the back with straps, and I'm thumbing the kill switch back and forth about 4-5 times, just verifying that the fuel pump is working. There's no gas going into the throttle bodies, even with the butterflies opened up completely and cranking for 8-10 seconds. I flipped the kill switch a couple more times, and suddenly notice that the main fuel line leading to the fuel rail has ballooned. I notice this about a second before it exploded.

What the hell is happening? Are my injectors clogged? Is my fuel pressure regulator broken? How could this happen so suddenly, with no indication that anything was wrong during my trip?

Sounds like you were just lucky it didn't happen while riding down the road. Mechanical things fail.

Bump. Any help?

Replace the broken fuel line and continue testing, if needed.

Well, OEM hoses shouldn't be bursting on a 9 year old motorcycle with less than 30,000 miles on it. There's obviously a problem and I thought the burst line would point to the culprit.

The fuel system does not put out enough pressure to burst a good hose.

The hose that is inside the tank in between the filter and pump that is held on only with spring clamps would blow to pieces long before the high pressure line would if the pressure could get that high.