78 GS400 Problems

[Elktrekker]

Hello, all.

Bike's been sitting awhile. I cleaned the jets, replaced the plugs, fuel filter and replaced the fuel. Bike starts and idles fine. A little sluggish at first, but gets up to 55mph very well. Then it dies and I coast to the side of the road. It takes a couple of minutes, and then I can start the bike again and start the whole process over again. This is consistant.

Any ideas as to the cause? Other info. The batt is dead, but I don't have electric start.

Thanks,

Drex

[gearhead13]

Sounds to me like the carb bowls are filling up, letting it run til they empty then it dies. Check your petcock and floats, kinked fuel line maybe?

[SqDancerLynn1]

You need to check the petcock operation, fuel line-don't make it any longer that necessary or it will kink. Did you put in a fuel filter? If you did make sure it is for a MC & also check the gas cap vent-

[Elktrekker]

Thanks for your quick replies.

I know the petcock works because I drained the tank just before assembly to put in fresh gas. I did replace the fuel filter with one designed for a motorcycle. The fuel line between the carb and the tank (with inline fuel filter) is short. At one point, I loosened the gas cap just to see what would happen. No change.

I'm not sure what to check with the floats, but when I had the carbs apart I checked to make sure the floats moved freely. What else should I look for?

Also, the vehicle will not run with the choke in the "down" position. I'm not sure if that's choked, or unchoked to be honest.

Thanks much,

Drex

[Baatfam]

Gas tank vent? I've had that happen before and it acts just like you described...
Try loosening the gas cap next time...

[mcloud]

Looks like you'll have to take carbs apart again.
Choke plunger down is "off".
Looks like your floats are stuck in the up position, or not properly adjusted. Choke plungers pulled up lets more gas in carb to warm up. That's why when you close your choke, it starves the carbs and dies.
Do you have a Haynes or Clymer book?

[Hoges]

Got to be fuel starvation as all the guys say, you'll have to remove them and check them out. Remember float level is done upside down usually. You have got the vacumn hose connected to the L/H carb which is under the petcock??