GS850 hesitates and misses from75-85 mph

[Scudder]

Heading out to the smokey mountians from Chicago in less than a month, and what do you know the 850 is missing a bit at speed and will not pull the way it did from about 70-85 mph. It doesn't happen every time which is puzzling. It started this in the rain a couple weeks back. It blew a fuse the other day, which has happened only twice in the last 5,000 miles.

My first thought was electrical, but now I'm leaning toward carb issues. When I got this bike I had to clean the heck out of the carbs and dip them 3 times to get to this point.

Starts fine, idles fine. It is a bit poppy in first gear if I don't let it warm up enough. 3rd and 4th gear seem fine and 5th is fine up to 75-85mph. Then it will sometimes miss and hesitate to continue to climb. I have always suspected that this bike is underpowered a bit.

I own a 1978 gs750 stripped down caf? racer that pulls hard in any gear, and is quick. My 1980 gs850 has a windjammer, hard bags and a trunk. The 850 seems a bit clunky to the 750. Probably not a fair comparison.

Any ideas? Probably carbs again?

Thanks,
Scudder

[eil]

I've read that a bad petcock can do this. At speed, the engine demands more gas but if there's a leak in the vacuum side of the petcock, not enough can get through and fill up the float bowls fast enough.

One test of this would be to cruise at low RPMs for a bit and then open it up wide. If it can maintain high RPMs for a little bit before it starts to struggle, that's classic fuel starvation.

[Badooka]

Could be some moisture in your gas- get some additives like Seafoam or such and run a tank through.
Wouldn't hurt to spray your electrical conx's with some WD40 to displace any moisture from the rain-

[Dogma]

You shouldn't be blowing fuses. Get a multimeter and start checking into it.

This may or may not be related related to your power problem at around 6k rpm, where my 1000G stuttered, just after completely failing to charge the battery.

Something is definitely wrong if an 850 fails to wake up snarl at you turning 6k.

[Scudder]

Upon further inspection of the carb/throttle cable area, I noctice the bottom nut that attaches the throttle cable to the bracket on the carbs was not present. It had unscrewed itself. That has to have something to do with throttle response. So I'm thinkin' maybe that could be the issue. I'll fine out I guess when I adjust things appropriately.

Think that could be it?

Scudder

[Dogma]

That needs fixed, but it wouldn't affect how smoothly the bike runs. It would just limit how far you can open the throttle.

[gearheadE30]

Check where the ends of the 2 float bowl vent tubes are hanging. They need to be in a stagnant air pocket. If the ends of those hoses are in turbulent air, or if the hoses aren't there at all, you will get some stumbling as turbulence increases with speed, and when you get hit by wind from certain angles.