Hey guys,
Im a new member here but ive been riding for a couple of years. Just traded my Honda Bobber for a 98 cbr f3 yesterday. I love this bike so far. Its got about 11k on it so far. My question is... When i traded, the previous owner told me that he removed the fuel pump, shortened the fuel line and is running off of gravity feed. the bike runs great until about 1/4 tank left. Then it will spit sputter and die. I have done gravity feeds on my other bikes and could always run the tank dry. is there something that you know of that could be wrong or is it just lack of weight from a full tank to push the gas down the line?
Thanks for the advice.

Mike

 

Hey, welcome aboard!

F3's were not designed to run without a fuel pump. People generally do this to bypass a busted fuel pump. And while it may seem to work, it really doesn't. You'll have flat spots where the fuel pump should have kicked in to keep the floats full. And I'm afraid the best diagnostic we can give you is:

Go buy a working fuel pump

 

Are you running with the petcock in the on position (down) or the reserve (up)?

 

wow whats up with all the fuel questions this week lol. ive had my fair share lol. i would replace the pump or... look up idodirt and look at his thread and vid about fixing your fuel pump. im in the process of fixing it right now. it seems the contacts on the switch that is located on top of fuel pump wear out causing you fuel pump to malfunction.

 

Thanks, it seems like this is a really good forum with some helpfull people on it. I thought that might be the case with the fuel pump. I guess ill just have to go and buy a setup. Do you recomend any place to buy a fuel pump assembly? i was probably going to use Ron ayers but if you know a place that is cheaper, please let me know.
Mike

 

i've been running with the fuel petcock in the on position. Why do you ask?

Mike

 

Yeah im going to have to buy a fuel pump since the previous owner didnt include the old fuel pump when i bought the bike, he just bypassed it and took it off. Thanks though

Mike

 

Try running with the petcock in the reserve position. This will suck fuel from the bottom of the tank and from the top of the stem looking thing in the tank that the in-tank filter covers - thus creating more pressure and a greater fuel flow. Give it a shot, I think you'll realize better performance across the board.

The problem with this is the whole running out of gas thing. If you keep an eye on your fuel level you'll be fine though. I've been running like this since March and haven't had any trouble with the gravity feed design or running out of gas.

 

cool man i will have to give that reserve thing a try until i can come up with the cash to get a new fuel pump assembly. How many miles are you averaging on a tank of gas?

Mike

 

It really depends on how hard I'm riding. It's usually something like 120 before I fill up. But like I said it all depends on how I've been riding on that tank, it could be more or less.
I'd give it a shot at least until you can come up with the cash for the fuel pump. Let me know how it works for you.