I've got a 96 600F3 that for about 3 years and has been good as gold. However, since I brought it back out of hibernation this winter it has developed a confusing problem. The bike will start and run fine for around 15 to 20 minutes with no hesitation or lack of power, and then over the course of about a minute. It seems to choke at high RPMs and then work its way down the RPM range until it dies. If left at idle after this process starts it sounds as if it loses a cylinder at a time until it dies completely. If the bike is left alone for around an hour it restarts and runs fine again for another 15-20 mins. I have replaced the usual: fuel filter, plugs and have checked all lines coming from the fuel tank and found them to be clear. If any of you have a direction to send me it would be greatly appreciated. Thanks


Mark

 

check the small hoses going to the tank. One of them is there to relieve the vacuum that builds up as fuel is used. If that line is kinked or clogged, then vacuum builds up and wont be able to get to the pump/carbs. Letting it sit for a bit allows to vacuum to bleed off.

The 2 small hoses..... one is for the vacuum bleed off, and the other is for gas tank overfill. Do this at your own risk.... but this is what I would do. Lift the tank off, disconnect all 3 hoses, set tank on a table or raised surface. Pull the 2 small hoses from the bike's center area (they lead to the ground), and recoonect the hoses to the tank. Remove the gas cap and try blowing into the hoses. If there is resistance then you found what should be a bad hose. Worse comes to worse, have a friend hold the tank up and blow directly into the nipples.

Like I said, thats what I would do, but do it at your own risk.

 

I have checked the tank vent line and found it to be clear. If i shut down the bike and pop open the fuel tank lid when the problem is happening there is no vaccum present. I have not checked the overfill line yet, but I will look into it tomarrow evening. Is there any chance that the problem is heat related; as it takes so long to the problem to remedy itself? Thanks alot for the tips!

 

maybe your ignition box is going out? If its not a vacuum problem, then if the box is overheating, or has flaky connections it might cause that. An overheating coil would do someting similiar, but only with one or twocylinders typically. However, is one of the coils is going bad, if it drops one then another cylinder that may be when the bike finally gives up, since it doesnt like trying to run on only 2 cylinders.

I think the first thing to try and unplug just about every connector you can find, make sure its clean, then plug it back in securely. After that I'd start thinking about electrical. Maybe get an ohm meter and see what the coils are measuring across he primary side (positive and negative, not the spark wire side).

 

It kind of sounds like the battery is dying. It's worth checking out since it won't cost you any money (unless you don't have a volt meter). Test the voltage of the battery before you start the bike. Take a voltage reading with the RPM's at 5K and then take a voltage reading as the bike is dying. You'll see the voltage go up and down with the RPM's. Your reading with the RPM's at 5K should be 13.0 to 15.5 Volts. If you are getting a reading below this level the entire time, than you have a charging system issue. It might not hurt to put your battery under a load test just to make sure the battery isn't failing when under a load. The battery will show a full charge when testing with a meter but when the battery is under a load, it fails quickly. You can take the battery to any battery shop or mechanical shop to test the battery out. You'll want the Cold Cranking Amps (CCA) which is 120 CCA. Don't take it to a stealership because they'll just tell you to buy a new one without even testing it which could be $50 to $100 (depends on the bat you buy) and might not even need a battery.

 

I am going to go check out the battery as I have a problem with it discharging over a few weeks time. The battery is less than a year old and is a sealed style "premium" (for whatever thats worth) battery. I have heard that the R/R is often times the culprit in discharging a standing battery. I talked to a neighbor (Honda dealership mechanic) and he pointed me toward the pulse generator. I plan of resistance testing that unit next. Thanks alot for the help guys!

 

I had a very similar problem. After some troubleshooting, I determined the rectifier was at fault. i replaced it with a used one I found off ebay and no problems almost 2 years later... Your bike could have a weak generator or other electrical problem...

You need to jump on ebay and order the service manual for your bike on cdrom. It's only like $5...

-GH