Hello Everyone,

I am new to this forum. My wife has a z400 with very low hours (under 10). It has not been run for about 6 months. The bike will start with the choke on but if you turn off the choke or touch the throttle, the engine dies. The bike is in GREAT shape, never abused. I hate diaphragm carbs, and dread having to open it up. I will do it if I have to. Thank you in advance for your input.

Marcus

 

pulling off the carb and giving it a good cleaning is just about the best advice
i could give you .
its really not that hard you dont even have to remove as much as you may fear you need to , pull the air intake boot ,remove the clamps from the carb to head boot and pull the carb out to the left side . getting the bowl screws out can be a pain ,there a bit soft and very easy to mess up with the wrong type of screw driver , when you get them out replace them with Allen head type screws ,get 7 of them 4 for the bowl and 3 for the throttle cable plate on the side of the carb . trust me you will be glad you did this the next time around.
you may have to drill out a plug that conceals a fuel screw ,or not ,turn the fuel screw in till it touches counting the turns in it take to bottem out and make a note of it ,when you replace the fuel screw turn it in then back it out the number of turns that it took to turn in.
the rest is rather simple clean it with carb cleaner and high pressure air blowing air into every crevasse and hole you can find , put it all back together ,have the fuel petcock on prime and push the start button

 

Thank you for the advise. I will tear into this tonight.

Marcus

 

Did you add fuel stabilizer to the gas before letting it sit for 6 months?

Gas starts to break down in about 60 days.

Sometimes you can get by just by draining out all the old bad gas and replacing it with fresh gas and sometimes it will then run fine if the problem is only bad gas. Since this is easier, you might try this 1st.

 

make sure all of the lines on the carb, and mess with the fuel mixture screw

 

put a lil seafoam in the tank might clear it out, see what the plug looks like also, maybe you can clear it up without having to pull the fuel bowl off.

 

<div class="FTQUOTE"><begin quote>Originally posted by: manybikes

Hello Everyone,



I am new to this forum. My wife has a z400 with very low hours (under 10). It has not been run for about 6 months. The bike will start with the choke on but if you turn off the choke or touch the throttle, the engine dies. The bike is in GREAT shape, never abused. I hate diaphragm carbs, and dread having to open it up. I will do it if I have to. Thank you in advance for your input.



Marcus</end quote></div>

It dies even after it is warm? Or while it is still warming up?

The correct starting procedure for the z400 is to start it with the choke on, then move the choke 1/2 way between on/off and let it idle until it is warm.....this creates a "fast idle" similar to what a throttle body set up in a car used to do...... then turn off the choke .....

If you touch the gas during that time, or turn the choke off before it is warm it will generally stall the engine......especially when you hit the gas......

The z400 like most Suzuki machines is warm blooded. Even when warm out, if it has not been started it needs to be choked and started the right way.

Only reason I ask is because I've seen a lot of people have this problem with the z400s.

 

I will put the choke to full "on" and it will start without any problem. If I even touch the choke lever or the throttle it die instantly. This even happens when the motor has run long enough to where it's hot tho the touch.

I have just taken off the carb and removed the bowl (fricken screws suck). I sprayed everything with carb cleaner, removed the main jet and made sure it was clear. Float seems to be doing it's job. I am now waiting for my wife to come home with a fresh 5 gallons of 92...

I will post as soon as I know something. Thank you everyone for your help.

Marcus

 

what about the fuel pilot screw ,did it come out all right ?

 

It seems to be fixed!! I think you were right, probably the pilot jet. I also cleared the jet, blocked in your picture by the main jet. It is idling a little high, with just a little sputtering. I would love to switch this carb out to a FCR. I want to keep this bike mild for my wife, no need for a rocket ship. I would just like a carb that is easy to work with.

Thank you everyone for your input.