[Bartman352004]

I acquired an 1994 f2 late last fall. I rode it last fall for a couple of weeks before putting it in storage. Before I stored it it was having trouble starting. I took it out of storage 2 weeks ago and tried to get it going. It tuned over well but would not catch. I suspected the the plugs so last week I changed them. In the process I cracked the gas line near the petcock so I decided to change the hoses out as well. I drained the tank, replaced the gas line, as well as the vacuum hose from the carb to the tank. I replaced the air filter and reattached a disconnected idle adjustment. The bike started great and starts every turn now however I am experiencing a stalling problem. I can run my bike for a distance of about .5 km and then it loses powers and stalls, The weird thing about this is that as soon as it stalls I can immediately start it back up and am able to continue for about the same distance and it dies again.

I am getting lots of power when I start again, but am not moving along very far before it happens again. When it comes to bikes I am a newbie so any help or pointers you can give me would be great.

I have a service manual but it does not help much beyong helping me find parts in the bike.

 

[mrmanr]

Try running some seafoam through tank, if anything probably need carbs clean. Do you mean bogging down or just completey dieing out. If its completety dieing out check your air hose, that would cause it to die and be able to start again, but die at higher speeds dud to lack of air. Just something to check. Might help.

 

[bladeracer]

I acquired an 1994 f2 late last fall. I rode it last fall for a couple of weeks before putting it in storage. Before I stored it it was having trouble starting. I took it out of storage 2 weeks ago and tried to get it going. It tuned over well but would not catch. I suspected the the plugs so last week I changed them. In the process I cracked the gas line near the petcock so I decided to change the hoses out as well. I drained the tank, replaced the gas line, as well as the vacuum hose from the carb to the tank. I replaced the air filter and reattached a disconnected idle adjustment. The bike started great and starts every turn now however I am experiencing a stalling problem. I can run my bike for a distance of about .5 km and then it loses powers and stalls, The weird thing about this is that as soon as it stalls I can immediately start it back up and am able to continue for about the same distance and it dies again.

I am getting lots of power when I start again, but am not moving along very far before it happens again. When it comes to bikes I am a newbie so any help or pointers you can give me would be great.

I have a service manual but it does not help much beyong helping me find parts in the bike.

Possibly a blocked tank vacuum - try riding with the filler cap open.
Is there any fuel coming through the vacuum line from the fuel tap?

 

[Bartman352004]

Just dies out. I suspect the vaccum hose, although it was replaced. The inside diameter of the hose I used was correct but the outside diameter is smaller. The hose is much softer and pliable then the original and may be collapsing on itself. What is seafoam? I don't live an an area where bike parts and accessories are readily available. Thanks for the replies.

 

[GUNBUNNY2BG4U]

REPLACE THE VAC LINE TO A STIFFER HOSE. AND SEAFOAM IS ONE OF THE BEST CARB CLEANER THE YOU CAN RUN IN THE GAS TANK. IT WILL CLEAN OUT THE CARB , INTAKE AND SUCH.

 

[Bartman352004]

Possibly a blocked tank vacuum - try riding with the filler cap open.
Is there any fuel coming through the vacuum line from the fuel tap?

I ran it twice today. The first time as is and sure enough it died out after a short distance. I did as you said an took a run with the filler cap open and sure enough it did not die out. There is no fuel coming through the vacuum line. I don't think the vacuum line is blocked but i might be wrong. It might sound stupid, again I am a newbie, but I was able to blow air into the tank from the vacuum hose and there is compression in the tank when I do. I let the hose go and the air in the tank releases. Conversly I was able to suck the air out using the hose (a free buzz here) and the tank decompresses and when i let the line go air is drawn back in through the line. The line does not collapse as I thought it might be doing.

Another question, there is a place for a second vacuum on another Carb. Where/What should this connect to?


I am a little confused on how this is all suppose to work. If the tank is sealed when I closed the lid, and the vacuum hose is sucking the air out of the tank, wouldn't that be causing my bike to starve for gas unless there is some venting into the tank? How does the tank vent the air in? I can see no holes in the tank cap, except where the key hole. Once I close the lid and it latches, the rubber seal keeps the gas in the tank. The overflow line won't bring any air into the tank because the lid seals off the tank from that area as well.


Is the tank suppose to vent from the cap?

 

[Bartman352004]

I was waiting to see if some else had some ideas but I took matters into my own hands. I fixed the issue and just in case anyone else has a similar problem, here is what i did.

I determined that the cap was the issue. I removed it and took it apart to see how it worked. I am attaching 2 images for you to view if I am able to.

This part is about my discovery, so you don't have to do this. If you look at the first image, you can see on the bottom left that there is a small hole. I expected this to be the cap vent hole but i was not sure. I removed the cap assembly from the tank and then the cap from the hinge.

Under the rubber seal of the cap there is a flat metal ring that can be easily removed. Once removed I was able to access 3 small screws which I loosened. I was then able to easily pull the cap plates apart to view a small rubber gasket with channel in it. The channel leads from the hole in the first image, to a cavity beneath the recessed part in the centre of the cap. I was not able to blow air through this hole when assembled meaning that my cap was not breathing at all. When I closed the tank and rode, the rubber seal was restricting any air flow into the tank so as I rode, the vacuum hose was decompressing my tank a bit and choking off my fuel supply.

I drilled a small hole in the centre of the cap, see the second image, and I was able to get air to pass from the centre hole to the breathing hole on the bottom left after i reassembled it. Now when I close my lid, the tank seals, however I now have a way for the tank to breath when I ride. The vacuum that was decompressing my tank, is now offset with this small hole I drilled into the bottom of the tank cap. This worked for me and may for you as well but let me first say before you do this, I am a newbie, meaning that although I am an experience rider, I am no mechanic.

I am just waiting for some guy with more knowledge than me to tell me how stupid I was to do this.

 

[bladeracer]

I was waiting to see if some else had some ideas but I took matters into my own hands. I fixed the issue and just in case anyone else has a similar problem, here is what i did.

I determined that the cap was the issue. I removed it and took it apart to see how it worked. I am attaching 2 images for you to view if I am able to.

This part is about my discovery, so you don't have to do this. If you look at the first image, you can see on the bottom left that there is a small hole. I expected this to be the cap vent hole but i was not sure. I removed the cap assembly from the tank and then the cap from the hinge.

Under the rubber seal of the cap there is a flat metal ring that can be easily removed. Once removed I was able to access 3 small screws which I loosened. I was then able to easily pull the cap plates apart to view a small rubber gasket with channel in it. The channel leads from the hole in the first image, to a cavity beneath the recessed part in the centre of the cap. I was not able to blow air through this hole when assembled meaning that my cap was not breathing at all. When I closed the tank and rode, the rubber seal was restricting any air flow into the tank so as I rode, the vacuum hose was decompressing my tank a bit and choking off my fuel supply.

I drilled a small hole in the centre of the cap, see the second image, and I was able to get air to pass from the centre hole to the breathing hole on the bottom left after i reassembled it. Now when I close my lid, the tank seals, however I now have a way for the tank to breath when I ride. The vacuum that was decompressing my tank, is now offset with this small hole I drilled into the bottom of the tank cap. This worked for me and may for you as well but let me first say before you do this, I am a newbie, meaning that although I am an experience rider, I am no mechanic.

I am just waiting for some guy with more knowledge than me to tell me how stupid I was to do this.

Looks like a nice fix.
But the tank doesn't breathe through the cap. It breathes through an internal pipe that is vented to the air.
The vacuum hose does not cause vacuum in your tank, it merely causes vacuum in the vacuum chamber of the fuel tap to open the fuel valve. The fuel level falling in tank is what causes the vacuum - if the tank can't breathe in air to equalise the pressure.

 

[Bartman352004]

Looks like a nice fix.
But the tank doesn't breathe through the cap. It breathes through an internal pipe that is vented to the air.
The vacuum hose does not cause vacuum in your tank, it merely causes vacuum in the vacuum chamber of the fuel tap to open the fuel valve. The fuel level falling in tank is what causes the vacuum - if the tank can't breathe in air to equalise the pressure.

Thanks for your help on this and for helping me understand the real purpose of the vacuum hose.


The internal pipe that is supposed to vent to the air is located where in the tank? I can see where the overflow is but I could not find any other pipes. There was only the vacuum line, gas line on the petcock and the overflow. I looked at the inside of the tank could find nothing. I ruled out the overflow as once the cap was locked, the tank was sealed off by it to this area. I would like to know for future reference.


Thanks again.

 

[bladeracer]

Thanks for your help on this and for helping me understand the real purpose of the vacuum hose.


The internal pipe that is supposed to vent to the air is located where in the tank? I can see where the overflow is but I could not find any other pipes. There was only the vacuum line, gas line on the petcock and the overflow. I looked at the inside of the tank could find nothing. I ruled out the overflow as once the cap was locked, the tank was sealed off by it to this area. I would like to know for future reference.


Thanks again.

I've never cut up an F2 tank so I don't know exactly, but if you look under the tank you will see the overflow hose and the vent hose. The vent hose is attached to the bottom end of the vent pipe that runs up through the tank to the highest point inside - usually around the filler cap area.
The overflow does the same but opens into the bottom of the filler cap well so fuel can drain out if you overfill the tank.

 

[Bartman352004]

Just a final note to everyone reading the post. The fix I have implemented has solved my problem. The bike has power to spare and I no longer have the stalling issue.

 

[murp117]

I have a 1992 cbr 600F2 that had the same problem. I tried the fix that you posted. It worked for me as well. Thanks for sharing.

 

[bigalsmuzik]

I HAVE A HONDA CBR 600 F3 1997 IT AS 3,000 MILE ON IT BUT I'AM HAVING TROUBLE WITH IT STALLING OUT WHEN I SWITCH TO THIRD GEAR. RPM GOES UP BUT BIKE GOES NO WHERE AND THEN IT CUTS OFF. I CRANK IT BACK UP AND ITS THE SAME THING ALL OVER AGAIN. CAN ANY BODY HELP ME WITH SOLVING THIS PROBLEM.PLEASE HELP

 

[bladeracer]

I HAVE A HONDA CBR 600 F3 1997 IT AS 3,000 MILE ON IT BUT I'AM HAVING TROUBLE WITH IT STALLING OUT WHEN I SWITCH TO THIRD GEAR. RPM GOES UP BUT BIKE GOES NO WHERE AND THEN IT CUTS OFF. I CRANK IT BACK UP AND ITS THE SAME THING ALL OVER AGAIN. CAN ANY BODY HELP ME WITH SOLVING THIS PROBLEM.PLEASE HELP

How long have you had the bike?
At what rpm are you shifting to third?
If the revs go up but the bike doesn't accelerate then it's probably clutch slip.

 

[davikan]

I determined that the cap was the issue..... This part is about my discovery, so you don't have to do this..... I drilled a small hole in the centre of the cap.....I was able to get air to pass from the centre hole to the breathing hole.....

I have what seems to be a related issue with my F2, so I'm hoping that someone out there will help me revive this thread.

When my F2 first came to me, an oil change revealed that the existing oil ran thin, and it reeked of gasoline. Also, the bike wouldn't start easily. I'd get a *click*, or occasionally the engine would turn over, but nothing else. The former owner suggested that when this happens, I should put the tranny into top gear, roll the bike backwards a few feet, and then try starting again. This helped - somewhat.

I've since determined that doing two other things after running the bike help even more: 1) Turning the petcock to "off" and 2) Opening the keyhole door on the fuel cap (I can hear a "hissing" noise when I do this.)

Remembering these three tricks helps most of the time. They certainly help avoid the gigantic puddle of fuel that used to form under my bike after every engine run.

However, the bike still stalls intermittently while riding. I'm too much of a newbie to ascertain if my shifting has something to do with the problem - I'd not be surprised if it did.

Still, I also suspect that when the bike stalls, the engine is flooded. After I try starting the bike a few times with the throttle held open, it starts up VERY sluggishly. After a few seconds, it smooths out, and I get underway.

Is my tank pressurizing itself when things get warm? Is this forcing fuel past the petcock into places it shouldn't go when the bike isn't running? Bartman352004: In one of your posts, you say: "This part is about my discovery, so you don't have to do this....." Does this mean that you do NOT recommend drilling the hole on the underside of the fuel cap?

Any help that you guys could offer would be MUCH appreciated. This F2 is my FIRST BIKE EVER, and I love it! I've been able to fix other issues on it (carbs have been taken apart and cleaned, rear brake lockup eliminated) pretty easily, but this one has me STUMPED.