Gs850 petcock

[Guest]

Just purchased a gs850 in fairly poor condition for a cheap price. My goal is to get it up and running for cheap as a first bike. Common things like valve lash, brakes, rubber lines, electrical and cables. The petcock was leaking terribly so I bought and installed a rebuild kit however it seems as though fuel flows in all positions except in the Prime position. This seems backwards to me but it's not leaking out of the petcock itself anymore.

[srg]

Welcome!

A common theme of the forums here: Stay far away from petcock and carb "rebuild kits." They, very often, have problems and have inferior parts. Shelling out the money for a OEM petcock is worth it. For carbs, check out http://cycleorings.com

BikeCliff's website has guides on all you mentioned (valve clearances, brakes, electrical work, etc). Check it out: http://members.dslextreme.com/users/bikecliff/

[tkent02]

Just purchased a gs850 in fairly poor condition for a cheap price. My goal is to get it up and running for cheap as a first bike. Common things like valve lash, brakes, rubber lines, electrical and cables. The petcock was leaking terribly so I bought and installed a rebuild kit however it seems as though fuel flows in all positions except in the Prime position. This seems backwards to me but it's not leaking out of the petcock itself anymore.

Look inside, at the aluminum pin with the O ring that shuts the valve when there is no vacuum. On some of the rebuild kits, the pin is too short, the oring never makes contact to shut off the fuel. I was able to make it work by using a fatter O ring.

Not sure why it doesn't flow on Prime, did you put something together wrong?

[Svtford4x4]

Thank you. I had not read about rebuild kit problems until after purchasing the kit. I quite possibly could have put it together wrong was trying to find documentation or guides on the assembly.

[sinkankan]

Petcock

When buying this petcock, check the outlet pipe is going in the right direction, obviously the OEM is the right way, but some after market ones go in the opposite direction, check the photo and compare with yours before you buy.
I had the same problem with my GS850, until I found one @ dkmotorcycles.

[Svtford4x4]

I put the fiber spacer in between the two rubber pieces lined the offset hole up with that of the housing. Do you happen to have more info on the oring.

[Svtford4x4]

Is there a spring inside the diaphragm end of the petcock because mine does not have a spring.

[Steve]

Yes, there should be a spring that pushes the plunger into its closed position. The diaphragm will pull against the spring to open it.

.

[Svtford4x4]

Bought an assortment of springs from the hardware store found one and stretched it to fit but I think it still needs a little more tension. Changed the oil. Freed up the cables. Installed new battery. Debating pulling the carbs and cleaning although I think they might need to be jetted because it has aftermarket exhaust and air filters.

[Steve]

Bought an assortment of springs from the hardware store found one and stretched it to fit but I think it still needs a little more tension. Changed the oil. Freed up the cables. Installed new battery. Debating pulling the carbs and cleaning although I think they might need to be jetted because it has aftermarket exhaust and air filters.

The diaphragm spring is not very heavy. It only needs to push the plug into place.

Pulling the carbs on your bike is a piece of cake. Even if you don't clean the carbs, you at least owe it to yourself to verify jetting.

On the other hand, remember that every shortcut you take only means you will be pulling the carbs one more time.

.

[Svtford4x4]

Alright great advice. I'll pull the carbs and take a look the bike wasn't running very good anyway had a bit of a miss. New to jetting ill have to do some reading up. After it runs well all that's left is front shocks and brakes and I should be ready for a test ride.

[Svtford4x4]

found out there was no jetting done and a jet kit would be cheaper than going back to stock. I bought a dynojet kit and started to install it today however the stock needle spacers do not fit the replacement needle (too small).