I have a 96 cbr f3 that is one headache after another...my main problem now is that the #3 intake manifold cylinder floods and nearly hydrolocks my engine....a little back ground on the bike= my fuel pump has a short somewhere so I gravity fed the carbs (which I have dissasembled and cleaned Several times recently) my thought is the gravity fed tank is overpowering the float needle but why would that only fload #3 cylinder? The needles and seats look good and the floats don't Stick...plugs are new...the petcock does leak from a bad oring but not bad enough to flood carb...and btw. I was riding the bike for a week or two with gravity fed carbs the all the sudden while riding it sounded like I dropped a cylinder and bogged down 5 miles from home ..it made it home then after parked I noticed fuel leaking from the #3 intake manifold overflow nipple just under the carb boot...which has no cover on #2 or #3 but #4 is covered with a nipple boot...wierd....so I changed the oil and unlocked the engine put a new cdi box in and started up the bike just to find the fuel leaking again from that same nipple on the intake manifold...will a tank less than half full overpower the float one one carb when gravity fed ??? And if so why would it run fine with no leaks for 2weeks?? Also if my fuel cut relay was bad would the bike still run??? Cuz I want to fix the fuel pump to rule out the gravity feed scenario...I have 2 fuel pumps that work when wire to a battery but when plugged into bike harness the bike dies...and only allows 1 click on starter button then u have to switch kill switch off then on for another starter button attempt..but when fuel pump is unplugged from harnes (black/blue and green wires) the bike starts and the starter can be pressed as many time as u want without having to reset the kill switch inbetween clicks...so I think its prolly the fuel cut relay that's bad but today I got it to start with normal set up (fuel pump istalled ) but the pump still wouldn't come on...iknow because I have clear fuel lines and know the pump doesn't always come on but it was letting the carbs run dry and not pumping any fuel to them while bikewas running...the 2 wires from the pump are black/blue (goes to fuel cut relay on subframe) and green (goes to cdi box next to cut relay) ...so basicly I need to know how to tell if the fuel cut relay is bad and why is my #3 cylinder flooding. And do I need nipple covers on all 4 intake manifold overflow nipples under carb boots?? The clymer manual doesn't say.....thanks in advance for any reply..this is my first post thogh I have read many !!!

 

#3 cylinder flooding sounds like a stuck float in the carb.

 

wow i thinkn all the problems your running into sounds like my bike 100%. i have rebuilt the carbs cleaned all the vents and hoses and everything else i can think of. a friend told me to try a crude temp check by touching the headers after just turning the bike on and trying to find out if all the headers are as warm as the others. the #3 header is significantly colder than the others (warm while the others want to burn my fingers off) sound slike i could be running into the same problems as you. start the bike gets gas but only for a second. will idle but sounds like garbage and when i give it throttle it chokes itself dead. does this sound familiar?

i'm thinking mine is just my fuel pump and plan on checking it tomorrow after im off work by bypassing it to see if it runs. if anybody out there can help please reply back. thanks.

 

same EXACT thing happened to my bike, #3 and everything turned out the fuel cut off relay went, so the bike was starved of fuel. found out by going through the diagnosis in the service manual. i bypassed the pump and it worked great. (the pump was good, just not working b/c of the bad relay). So i went and got a used relay (from a 2007 Honda Shadow VT750DC), works great now!

Part number 36100-MN4-008 , honda uses them on their bikes since the 80's. find what others models here

http://fiche.ronayers.com/Index.cfm/Module/WhereUsed


get a multimeter and check the relay

 

thanks man will do. ill let you know when i get my hands on a multimeter to check it.. should be this week.

 

radio shack "rental" program =D

 

good look, thanks

 

emmm... but if he said that it "floods the cylinder" then , that doest has to do with the fuel cut relay.. am I right ? (I think the float should be stuck)