I've got a problem that started on MLK day when I rolled my Z400 in the. I haven't been able to figure it out. Have had the quad since new in 2003 and never had a problem with it. Whatever is going on started after the roll.

Just after the roll the quad started and I rode for a while but then it started sputtering real bad and died and I could not get it started. Checked the plug expecting to see it was fouled but it was perfect. K&N is clean as well.

Been trying to figure out what the problem is and have found that if I switch the petdork* to PRI it starts right up and runs perfect. I can't start it with the petdork* in the ON position. If I get it started in PRI and switch to ON it runs about 5 minutes until it starts sputtering and then dies.

With the petdork* in the ON position the carb pulls fuel with a vacuum. In the PRI position fuel flows vacuum or not. So, I think what is happening is I set it to PRI, start it up and a good vaccum builds - I switch it to ON and over the next 5 minutes or so the vacuum is lost and eventually there is no more fuel flowing so it dies. I'm thinking there must be a vacuum leak somewhere but I can't find it.

Any thoughts? Any Z400 owners out there have had similar problems.

Have you checked to see if the gas cap vent is clear? Also you might want to check the carb and the petdork* and make they are clear also.

Hustler,

Yes, the first thing I checked when it happened was the vent. No problem there.

I took the fuel line off the carb and opened the petdork* on PRI and the fuel flowed with no problem. When the petdork* in in the ON position it will run about 5 minutes before it dies so I know the fuel is flowing that way as well.

I'm thinking that since there is no problem in prime and it only dies over time when vaccum fed that there must be some loos of vaccum until there is not enough left to draw fuel.

Thanks, Mark

Turn the fuel valve to on and apply vaccum to the vaccum nipple, either with a vaccum pump or your mouth. It doesn't take much pressure and no fuel will be sucked into your mouth.

If you apply vaccum and fuel comes out, you know it isn't the valve. I think something might have been disturbed and plugged your main fuel valve oriface.

The Z petdork*s are known for that.

You may also want to check the vacuum hose for any tears or loose fitting from the carb to the petdork. any leak will cause the vacuum to malfunction.

I already checked the vacuum hose and it has good tight connections so there is no leak there. I'm going to take it off to see if maybe its clogged. I'll also add some vacuum to see if fuel flows when the petdork* is on.

I'm also going to take off the petdork* to see if the filter is clogged. I've seen a lot of complaints about this.

Thanks.