for the last couple weeks ive been riding my f3 to work everyday (an hour each way) and usally once a day it will cut out on me while riding. I can always tell when its coming because the bike starts to jump like its not getting any gas. ive tried to throttle through it but that never works. after it starts cutting in and out, as soon as i pull the clutch in for a stop sign or light, the bike dies. lights are still on but the engine isnt running anymore. I'll pull off the road; put the choke on and it'll start right up after a few seconds of turnover. My tank was creating a vaccum for a while so i thought the vents were plugged and overpowering the fuel pump to where i didnt get any gas, but even after opening the tank it would still cut out. but like i said, it only cuts out once a day and has never failed to start back up.

its more annoying than anythings else but does anyone have any idea whats going on?

thanks,

 

i just read this other thread on the forum. its a DIY on how to replace your fuel pump contacts. my bike has just over 21,000 miles on it but i dont know if anything was replaced or modified before i bought it.

https://cbrforum.com/forum/stickies-91/how-repair-your-f3-fuel-pump-102151/

 

Before you go spending money on the fuel pump, I would fix the vacuum effect that you're experiencing with the gas tank. I would actually try riding the bike with the gas cap open. If the bike still dies then you can at least rule out that vaporlock as the problem. If this fixes it, then you just saved $40 on the fuel pump contacts.

I had a very similar problem with mine, I had slight rust in my tank so I got a etching and sealing kit for it. Well when I sealed it I sealed right over the vent that lets the pressure equalize. At high speed or after twenty minutes of riding the bike would start sputtering and eventually die on me. I would pull over to the side of the road, open the gas tank - which let the pressure equalize - and the bike would start right back up. I finally tried riding with the tank lid open to see if that's what was causing the problem, and sure enough it was. What I eventually did was drill a small hole on that little lip underneath the cap. I haven't had any problems with it since. Only problem is if you're cruising and need to get on the brakes really hard for whatever reason and you've got a full tank, you get a little bit of a spray.

Hopefully this helps, we all know how embarrassing it is to be cruising down the road and just have your bike die on you... especially if you've got a pretty gal on the back.

 

where does the vent lead? when i open the gas cap i can see the vent hole but when i feel inside the tank it feels like its a hose that runs down the inside of the tank. im not sure where that goes or how to check it

 

It's hard enough to see into the tank to see where it goes, I couldn't imagine getting a hand down in there to check it or clean it. It ends up on the right hand side of your gas tank at the top though, immediately right of the cap.

I'm at work right now but if I can remember correctly there are 2 hoses on the bottom of the tank near the petcock. This is the skinnier of the two.

Maybe try taking a compressor from the bottom of the tank and blowing whatever it is in the tube out. I'm not sure if that will do the trick, but I reckon it's worth a shot.

Also... that vent hole that you can see isn't the vent hole that I'm talking about. I think that's just like a drain for rain water or if you overfill on gas or something. It plumbs out to the bottom of the tank and doesn't affect the actual pressure in the tank.

 

I'm at work too but not doin much haha.
that makes a little more sense. the only problem i have with that is when i take my gas tank off i only have one hose..i must either be not noticing it or its not there, but when i take the tank off all i have to do is take the gas line off. there is no other hose on the the tank..im almost postive and ive taken that tank of probably 50 times already.

 

These are the best days at work. Getting paid to sit and do what I would be doing at home.
The hoses I don't think are really necessary, they don't connect to anything, they just plumb the drainage away from the underside of the gas tank back towards the swingarm. There should at least be some inch-long metal things on the bottom of the tank where you could suspect the hoses to be though. They're pretty much right next to the petcock. The bigger one runs all the way through to the top and acts as that drain almost. The other is the vent and will be the one you've got to deal with.

 

i'll have to look at it when i get home tonight..ill lelt you know how it goes.

thanks for the help

 

am i the only person who sees the danger in this? ride with the cap open? accidently crash and have fuel go everywhere? no one intends on wrecking but it happens. how about: dont ride with the cap open. find other ways to deal with vapor lock. 99% of us dont have vapor lock issues. try to find out what is causing it. dont try to half-*** the problem. see what your bike is doing different than ours and completely FIX the problem.

 

I have to agree. All you have to do is hit the brakes to hard and splash of gas out over the tank and onto a hot part.

2ndly..... Cinder, you drilled a small hole on the top of you tank and get sprayed by gas???? Do you ever ride in the rain or leave you bike in the rain? How do you keep the water out of your fuel?

Besides that i keep seeing "Vapor lock" being tossed out here. This is not a correct condition of vapor lock. Vapor lock is when the fuel in the lines and/or carbs turns from a liquid state to a gas state. Most of the time it happens when the fuel system is not flowing and is very hot although i have seen it do it on a running motor that was overheating.

I do see what your trying to say with a vaccuum effect occuring in the tank will not allow the pump to pull and fuel out. If im not mistaken under our stock fuel cap assembly there is a small vent hole thats not visible unless you take the cap assembly off. Ill have to look at mine i have the tank apart for paint and ill post what i see.



Look up post by Idodirt. He has alot of knowledge on the fuel systems and electrical on our bikes. He has a great thread on fuel pump contacts and it may help you.