93 900rr fuel pump ops questions
 

Ok so I got my 93 running 😀 but I'm curious about the fuel pump operation. When I got the 93 the pump was said to not be working which I found out be false it was a bad relay so I replaced the relay. But now the bike is running and with the fuel pump relay in and working I have fuel pooring out of the overflow line from the carbs but if I take the relay out she still runs well and no fuel is pooring out the overflow any insight is greatly appreciated cause I'm stumped

I know this thread is somewhat old but I had the same thing going on with my 1989 CBR600F. I eventually pulled the carbs, sent them out for a complete rebuild, but haven't got it running again due to some other priorities. I'm hoping that this problem will have gone away and that it was a sticking float or a bad seal in one of the floats. Interesting that it doesn't do it with the pump off, that could indicate that one of the float bowls is being pressurized by the fuel pump.

Anyway, if you are still around we'd appreciate an update.

I recently read something about getting a gravity fed fuel petcock and bypassing the fuel pump altogether on these bikes......as I get my basket case 900rr put back together I might have this problem. It sounds like stuck floats to me!!

I pulled my carbs back off and checked the float bowls. One of the bowls the needle jet had not ended up in it's seat when the carb bank was rebuilt. I put it back where it was supposed to be and fuel no longer overflows. Still doesn't run but at least fuel doesn't pour out of overflow.

I have a 92 RRN and have removed the fuel pump altogether. Rumours doing the rounds before I did it said that I'd have no problems except that range on reserve tank would be less as I wouldn't get all the fuel out of the bottom of the tank. Can't say I've noticed as I fill up not long after going onto reserve anyway.

As for connections, can't say i remember how I did it other than to remove the pump and wiring.

is it still not running because of other priorities or because you have another issue to fix as well?

Thanks for the update on the float bowls.

Yes. I have a frame up Harley from a major wreck that I was in years ago and I work two jobs, one of which is being a Harley mechanic. By the time I finish the hours of working on other people's bikes, I don't have a ton of enthusiasm or energy for working on my own.

And there are other problems. I added a cheap fuel pump (I'm told they catch fire and I shouldn't use it but for $16 if I can get the bike running properly I'll upgrade later) and it fires but doesn't run for more than a couple seconds. Dennis suggested pilot circuits which is frustrating given that I paid decent money to Wired George to rebuild the carbs. I am going to pull the bank back off and check the pilot jets, and then ... I don't know.

I also bought a parts bike for $100 and I'm stripping that down to get it out of my garage as fast as possible. Life. In a perfect world I would have three running bikes, no parts bikes, and all my customer's motorcycles would come into the shop in the morning and leave in the afternoon.

Oh and all the students in my math classes would be super focused and enthusiastic about learning.