Hey guys,

So here's the story. I just bought a motorcycle in Nashville. I live about 2 hours away from there. I drove the motorcycle on Saturday evening when it was 110 degrees out. The bike ran GREAT. Like... Flawless. No problems, whatsoever.

I stopped at my house to cool off, and I didn't turn the bike back on for about forty minutes. Then, I turned it on, and rode it around. I stopped, and the bike just died. I thought that was strange, and I turned it back on, and it started acting like it wasn't getting any fuel? I haven't been able to look at it very much, but I got out a voltage meter, and checked the terminals on the fuel pump. The voltage would spike, after turning the motorcycle on, and then it would turn off before a second had passed. So I'm figuring that one of the relays controlling it has gone bad, or something ridiculous?

p.s. checked the main fuel pump relay with the 5P, and it is working just fine. (I have an extra fuel cut off relay off of an old 96 cbr f3,and it's the same part, I was just going to put it on there as a "quick fix" and see if it will start)

I had someone else offer up that it may be vapor locked? I will go about checking that first when i start working on it again...

Thanks for reading!

Alex

 

the fuel pump on an F4 is not a continuously running one.. it will actually pulse on and off while running every few seconds.. You can actually bypass to test if the fuel level is high enough.

When you say that it wont start.. will it crank? Do you smell fuel? Check the petcock under teh seat but I doubt that is the case.. it could be vapor lock.. who knows.. so pop the gas tank open and then close it and try again...
you could check for spark but that means takin the tank and some trim off to get to the plugs..

 

Strange. All i did was put the relay back on after I tested it, and..... the bike works beautifully. Started like a dream. Does that make sense? Nope! but I'll take it. I'm not going to ride it for 2 hours (ish) in 110 degree weather again...

Thanks though!!

 

you might want to think about packing your connections with dielectric grease. Not critical but it will help with the connections keeping their contacts.