Hmm, maybe that check valve just sucks in? I didnt think of that. However I put about 4 hours on the quad today and the tank didnt hiss.

 

mastrblastr email me. plainsman@wah.midco.net

 

Plainsman, email and PM sent.

 

Here's what my kawi dealer/machanic says;

The tank IS pressurized, it's pressurized by 3 pounds even.

I asked why, he said the only reason he can think of is to help keep dirt and water out. He said people have vented them straight out with no problems but he does not do it.

I asked about the beer can effect and he said the valve releases extra pressure and also won't let it below 3 pounds pressure, probably the real reason. Only Kawi really knows why he said and how, he just maintains them. It some kind of two way valve with difference releases.

That is also why the Brute has an automatic shutoff now.

Hope this stops people from thinking there is a problem with pressure in their tanks, when there is none.

She's under pressure, 3 pounds pressure.

 

It has been so long since I "vented" my tank, but I think the valve was restricted on both inlet & exhaust... DOA... I don't know how the tank could build pressure, ( the pump draws no outside air ), except for the "warming up effect"...unless its after the tank warms up, with the quad not consuming gas... I'm betting that most people are hearing both a suction & or a venting of pressure, ... but, the 3 psi sounds about right for the restriction on the vent valve... so if thats the case, then likely the tanks pressure would vary between - 3 psi, to + 3 psi...

BTW... I have never shut my gas off once... even during transport... & never had problems with the gas leaking past the carbs... IMO, if the float valves are seating properly, gas should not get past them ( the V Force is nearly the same set up, but the shut off valve is not easily accessable, so it's not recommended to shut of it's gas after use )... I'm betting that any problems with gas "hydrolocking", is related to a partical of dirt, or build up of sludge, on the valve seat... I always am very carefull with the gas I'm putting in, I always add Stabil to the gas ( as I fill from plastic gas cans, & I never know how long the gas will be stored in the can ), & I installed an in - line gas filter in front of the carbs

 

When I owned my Prairie, I had the same problem with pressure building up in the tank and making a swoosh sound when I open the cap. Talked with my dealer and he told me that there shouldn't be any pressure built up in the tank and Kawasaki was having problems with the check valve. My dealer is very very knowledgable and knows his **** and he told me to bypass the checkvalve. I did that and didn't have a problem after that.

 

How did you bypass yours?

 

The service manual doesn't say anything about the tank being pressurized so that is what I will go by. My 650 runs awesome with no pressure in the tank, so that's how I'm gonna run it. If it is pressurized, this is a first I've ever heard of. I've never owned a vehicle in my life that has a pressurized tank so why would they start now? Doesn't make sense. The manual says the fuel pump delivers between 2.6 to 3.3 psi. It doesn't say anything about the tank having 3 pounds of pressure in the tank. I'll go by the manual as it has never let me down before. I can't say the same for a lot of dealers.

 

I do know some GM cars/trucks had issues when the gas caps were loose. Does the service manual address the fuel vent in any detail? Is it 2 way, or a 1 way check ect?

 

Hey DOA, you know what would be cool, is add a pressure gauge inline for a little bit just to see what kind of pressures build. If its blowing masterblasters cap off its a lot more than 3 lbs. It sounds like a darn smart little $22 part that can measure 3lbs in/out.

I would guess by the hiss I was around 10+lbs. When I go to the cycle show this weekend Im going to drill a Kawi rep about this.