Jets?

[Anonymous]

Alright, I just bought this bike, 1981 GS850GX. She has 18000 miles on her. She's clean, but I just can't figure out why 65 is her max speed. I checked the fuel cock. There is an inline filter on the fuel line. Could that be the problem? What's next? My dad says the jets may be wrong for this altitude. I live at 6000 feet, but I bought the bike from a guy selling it for a guy from Idaho so.....Anyhow, any input? My bike looses push at about 4,500rpms in 5th. Thanks for everyones time----Levi

[daveo]

Re: Jets?

There is an inline filter on the fuel line. Could that be the problem?

a good place to start, followed by the petcock itself and the screen on the petcock inside the gastank, you must remove petcock to inspect the screen. Check for kinks in the fuel line or leaks in the vacuum pull-off line that operates the petcock also. Your bike should have CV type carbs, they compensate for altitude by their design and are probably not the problem

[first timer]

are you running the stock air box? stock exhaust?

-ryan

[bwringer]

I've been up to about 6300 feet on my GS850 and it ran fine, so altitude isn't your problem.

As others have said, first verify that you're getting a good supply of fresh fuel. Fuel line blockages from crud and rust in the tank are very common in neglected bikes.

It's also common for rust and crud to build up behind the filter screen under the needle valve seats in the carbs. (Check the carb rebuild series.)

I would definitely check wet and dry compression to make sure the valvetrain and rings are fairly healthy. I'd also check the valve clearances before running it much more.

Let's see, what else?... Inspect the intake boots and their o-rings, too.

http://bwringer.com/gs/intakeorings.html

http://cycleorings.com/intake.html

And while you have the carbs off...

http://cycleorings.com/

http://bwringer.com/gs/camchaintens.html

http://bwringer.com/gs/carbsync.html

Not of this is very difficult or expensive if you take your time and have at least a little mechanical aptitude. Even with a brand-new bike, just one winter of neglect can wreak havoc in the fuel and electrical systems. Your low-mileage GS850 has certainly endured far more neglect than that in 23 years, but you should end up with a nice, reliable bike with a little patience.