ran for 20 minute just fine, now won't stay started!?

[stephen2us]

New problem with xs400 1981 special... bought it in spring, rode very little, but it has always started and ridden fine the small number of times I have rode it this year. Took it ought today for a 20 minute ride, and only thing I did after was adjust open the idle mix screw a little, because it was running lean, (ive adjusted it before with no problems of running/starting).... First thing that happened afterwards was the idle slowly kept getting slower, and then died... now it just dies very quickly no matter what. It will start, but dies, even if I have choke pulled out, it now dies after a second of running. I've moved the idle mix screw back to where it was, but now it doesn't matter...

Any ideas where i should start..?
Thanks

 

[stephen2us]

took off air filters and squirted carb cleaner in while starting just to see.... and it started and ran as I was pouring carb cleaner in ... temporarily...

 

[bcware]

Sounds like a classic dead battery to me. Test the battery. If it turns out to be dead replace it and verify that the bike is charging. In my experience the bike will run without a charging system on a full battery for about 20-30 minutes before failing.

 

[Jtoroli]

If you can eliminate the battery as a culprit and assuming you have good spark to both cylinders I would check the fuel delivery. Remove tank and using a squeeze bottle fill the carbs see if it starts. If no then I would remove the carbs and check the idle circuit. It has 2 very small jets that can get easilly clogged.

This however is odd because the Choke should provide enough fuel with the throttle closed to run. Are you getting fuel to carbs?

I took the tank off my recently purchased Seca and fuel just dribbled out due to sludge packed around the petcock screen. It had the same symptom you are describing. Carbs rebuilt runs great on a test tank.

Just some thoughts.

Joe

 

[stephen2us]

Thanks for the replies all... battery checked out fine, so when I got home an hour ago, I started from fuel tank and worked by way back... took off hose right after petcock and before inline filter, got fuel flowing fine.

THEN, took hose off before carb, and AFTER FUEL FILTER, and nothing... nothing was coming out... so the all this from a clogged fuel filter--just replaced fuel filter, PRIMED, and it started right up!!! Glad it was a $4 fix!!

Thanks again gang...

Steve

 

[Jtoroli]

Hey Steve,

Glad to hear it was a simple fix and that you are up and running again. BTW how is the inside of your tank? Just curious as I am getting ready to de rust mine.

Joe

 

[arfstrom]

What a Great thread, pointing out the need for a filter, Thanks!
Tobie