Bad hesitation when cruising--whats going on?

[schmmt]

I had the same problem. I took the o-ring off the vacuum petcock needle on the tank and added an inline fuel shut off valve. Which also increased the length of the fuel line and it's path to the carbs. Nothing but trouble. Has anyone had any luck with inline shut off valves? there is very little room to get one in without running the fuel line horizontal for a short length.

[GSstiny]

In your first post you mentioned that your carb spills gas every now and then. That's not right. You should fix that before trouble shooting anything else...

Yeah, I know I need to. I think its just dirty because its just once in a while. My temporary fix is the drain hoses, but as soon as finals are done and things settle back down Im going to get a set of robert barr's orings and clean/reseal all 4.

[matt_gs450]

Similar problem with an 81 GS 450

Hi,

Did any of these suggestions address your problem? I have a similar hesitation problem with my 81 GS 450. It is intermittent, and seems to show up when I'm cruising at low-mid RPMs (around 4 or 5,000).

I suspected some of the same things; some sort of clog in the petcock assembly, or some problem with the fuel mixture. I'm not a mechanic, just a recreational rider, so I'm not sure and don't want to start pulling stuff apart. I also don't want to take it to my mechanic with a vague description.

Thanks,
Matt

[wiredgeorge]

First thing I thought of when I read the complaint was that it was sporadically not pulling gas. Couple of reasons this can happen... the gas cap vents plugged as already mentioned. Also, you probably have a vent or vents on your carburetors. If these are obstructed in any way, the float system doesn't work well. There are OTHER possible reasons as this seems to be related to a specific engine speed. I am guessing there is also a possibility that the mechanical ignition advance on your bike is not able to rotate freely and thus, the ignition curve is not advanced as it should be. You need to remove the part that goes over the crank and on the end of the advance and clean it and the advance and then lubricate it as part of your normal maintenance routine.

[GSstiny]

Matt, my problem was that the bends in the fuel hose werent allowing it to flow like it should. I rerouted and shortened the hose and was trouble free unitl my latest saga. Make sure fuel is flowing through the petcock, and to the carbs, then go from there.

also, make sure your petcock isnt on prime. I did that once too.