Hey, I just bought a cbr 600 f 1989. The problem: When not driven regularly the fuel pump doesn't seem to work properly. The motorcycle starts fine and after a mile or so it dies (it feels a little tacky before it dies). It seems to me that it doesn't get gas. But when I give electricity to the fuel pump straight from the battery, it starts again and drives a lot better. After this jumpstart to fuel pump, the pump starts pumping and it drives better than before. It feels like the problem goes to way, and it drives like normal. Unfortunately, i can't take it to longer rides because i don't have a license yet, but at least for like 5 miles its fine. And the next day, it's the same problem all over again. I have tested the fuel pump capacity with no other variables and it pumped in 5 seconds like 300cc (seems a lot to me). I have tested the connections between the pump relay and spark unit (continuity) ; the pump relay and fuel pump (continuity); and the relay's connector and it shows the battery voltage. Have inspected the pump and the electrical connections seems fine and no wires are disconnected.

So the problems goes to away when given straight power momentarily to the pump from the battery before driving. Some with similar problems have had problems with r/r, alternator/stator. I dout the stator or alternator as I don't have any other electrical problems: the battery doesn't die. I have done the regulated voltage inspection and 5,000 rpm hovers around 14.5 V. Idling around 13,5 V, 13 V if I put high beam and blinkers and other electrics on. I wouldn't want to buy the unnecessary parts so where should I begin? Any other ideas what might be the problem?

Sorry for the long post and English, and thanks.

 

Hi Rider123,

Please take a moment and pop over to the new member area to introduce yourself to the forum.
Where are you from, how long have you been on two wheels, what bikes do you have etc.
We also love pictures.

I am not that familiar with the F2's but it might be carb related and all you are doing is filling up and using what fuel there is in the float bowls...
Have you had the carbs off / cleaned?
Was the bike sitting for a while before you had it?
Are all the vacuum pipes properly connected?

Cheers
​​​​​​​Al

 

I agree with the above as the fuel pump isn't totally needed to deliver fuel look at things like fuel filter fuel tank breather through cap etc or sticking float bowl valve as it sounds like your using up available fuel check the fuel is free flowing from the tank under gravity for a reasonable length of time into a gallon can without the pump connected this will tell you that it's not a vacuum problem in the tank. I have the F1 1989 cbr it doesn't have a fuel tap vacuum connection does Yours as I'm not sure when they started with them it could be the pet-**** or the nylon in tank filter attached to that but everything your saying sounds like starvation. You can bypass the fuel pump and run on gravity with no ill effect I believe ! good luck and welcome to the forum, best do intro bit too. AL.

 

Hey again! Yeah need to introduce myself a little. But I also have suspected the carbs, but as it seems to run so well after giving electricity to the fuel pump. Do you think that it could run little over 5 miles solely on gas from float chambers? The previous owner said that the carbs are checked and cleaned, but if the problem doesn't go to away, I need to start looking at them. I just thought it must be some part of the fuel pump or electric part as the pump didn't run at all when driving/idling. And when getting the pump running and confirming by feeling it, the problem went away. Sorry, but where is the fuel tap vacuum connection located? Vacuums pipe looked fine after taking the air filter box off. Yeah the problem is starvation for sure, I just thought it would be because of the pump. The fuel filter and carbs are on the list now.

Thanks for the help