Hello everyone. I joined this forum in hopes of finding helpful info diagnosing a NO-FUEL-FLOW problem I am having with my Yamaha Kodiak 400.
I am the original owner of the atv, and until fairly recently I have had no problems.
The first symptom was the fuel bubbling inside the tank followed by the atv stalling. When that first happened I would go to unscrew the cap and a massive amout of built up pressure would release, shortly after, the atv would fire and run under load for a half hour or so... and then do it again.
I disassembled the fuel cap for inspection and it appeared clean and the vent tube had no obstruction. Something I did may have corrected that problem because it only did that a dozen times or so and has not done it since, but the bike continued stalling...
Next I cut the factory fuel hose in half and installed a clear inline filter to moniter the system for debris or lack of flow. Ran great for several hours afterwords and then died out again. I checked the inline filter and it was bone dry. I then removed the fuel line from the carb and the fuel instantly started flowing freely through the line (and filter). I reinstalled the hose to the carb and the bike fired and ran great for a while...and then did it again!
By now I am frusterated because I cant seem to diagnose such a simple system
Months go by as I let my atv sit out of frustration and lack of trust in my machine.
Next I decided to remove the carb (for the second time) and took it to my local bike shop to be gone through. I also replaced the fuel cap and fuel **** while it was apart (with factory Yamaha parts) and checked all vent hoses for obstruction.
Short story long, I got my bike all back together today and within 30 min it died and sure enough the FF is bone dry so its not getting fuel (still)!!!

I appologize for the lengthy post but I wanted to provide some decent background info in hopes one of you may be experianced with this same sort of issue and be able to offer some advise.

Thanks - Dave

 

seems just like a vent somewhere isnt letting either the carb or tank breath still, without that the fuel wont flow at all, have you tried running it with no gas cap and tried taking the airbox off to see if anything changes, seems like the fuel system is being choked for air.

 

Thanks for your reply.
I have tried removing the cap but I have not tried running it without the airbox. The air filter is also brand new (OEM Yamaha filter) so I cant picture that as being the problem.
With the clear universal inline fuel filter installed, I can clearly see that the filter eventually runs itself dry which is when the atv dies. I have tried running the **** valve in the run and also the reserve position with no change.
Do you think it is possible the FF is creating enough resistance to not allow the fuel to gravity feed properly?

I am going to go pull the fuel tank (again) and recheck all vent hoses and replace the fuel line going to the carb and reinstall it without a inline filter and see if that corrects the problem, unfortunatly without the inline filter installed I will be unable to visually moniter the fuel flow.

 

Hmm its gotta be simple...none of the vent lines off the carb are blocked/clogged i wouldnt think the inline filter would stop flow at all unless it was maybe too big of one or something i know i use them with zero problems

 

Whoa there partner... You missed something. The petcock. Remember it probably has a small screen. If you have gunk in the tank, guess where it all goes? Also, with this much problem, I'd replace every single piece of fuel line you can. It is cheap.

I have had spiders build nests in Carbs, fuel lines you name it. I suspect you will find something there that you missed. That would account for vent problems. Also, soft rubber will collapse when the motor is running, then return to it's regular shape when the engine dies. Hmm, sound familiar?

 

Thanks for your reply Dragginbutt, but yes I already replaced the petcock with a brand new OEM Yamaha part.

When I first got the bike all back together it ran itself out of fuel one time after about 20 min. run time. Since then I have rode it for about 2 hour's and it has not done it again... (yet)

My biggest problem is I have lost my faith in my machine. The places I take it camping I can not afford to have it die
My once a year "big camping trip" is less than 2 weeks away now and I will still be going, but I will restrict myself to staying on the main trails in case my ride decides to act up... time will tell I suppose

 

Not sure how the Kodiak is set up but alot of machines have a mikuni style fuel pump that works off of engine vacume, if not that there should be a gas tank vent line off the cap or under the plastic on the tank that vents up high by the handlebars.

 

No fuel pump on this machine just a gravity fed fuel system. The cap is vented and does have a vent hose that runs up near the base of the bars. That hose has been replaced along with the new OEM cap.

 

Dave if you have munki carb there is an internal diaphram normally has a cover on the side of the carb with 3 screws under the cover there is a spring then a rubber diaphram with a rod on it. i was having hte same problem with my 95 kodiak i pulled the cover off to find a very small hole in the rubber diaphram. this opens and closes in the carb to bring the fuel into the system. hope you get your trust back in the machine and have a great ride this summer.