86 FJ petcock issue

[TobinM]

I picked up an 86 FJ1200 a couple weeks ago and one issue I've been having is the petcock continues feeding fuel after the bike is shut off. It doesn't happen every ride so I don't understand the issue. I'm thinking that the vacuum just gets stuck open sometimes, but I don't know how to fix that. If this makes sense to anyone and if anyone has a fix I would appreciate it. Also if it isn't the petcock what else would leak my whole tank on the floor.

[twood1972]

Tobin.
Your diaphragm is most likely faulty. RPM has a rebuild for reasonable. Best just rebuild it and save yourself the worry. Suggest checking your crank case for fuel contamination. Don't forget to safety wire your outlet pipe on your petcock as they have been known to fail.

Congrats on your new to you FJ.

[red]

Tobin,

You have at least two problems.  The fuel petcock needs attention, yes.  Clean, rebuild, or replace it.  Your carbs should also stop the flow of fuel, and if they do not, they need help also - clean or rebuild as necessary.

As said in the post above, leaking carbs can dump fuel directly into your crankcase, destroying the oil.  If you smell fuel at the crankcase oil filler hole (remove the oil filler plug and sniff), or if the engine oil level increases mysteriously, then DO NOT run the engine until the fuel problems are completely fixed, and you have replaced the bad engine oil with new oil. 

Fuel leaked in the engine oil can ruin your engine and transmission.

[Pat Conlon]

Buy a new 84/85 petcock from RPM and be done with it. You lose that wonky reserve function, but, so be it. You already have a gas gauge, a fuel light and an odometer. Electric reserves are stupid.

http://www.rpmracingca.com/proddetail.asp?prod=M%2FC%3A36Y-24500-01

I have never had good luck with the aftermarket petcock rebuild kits.
40 years of being in a hot under tank environment takes its toll on petcocks.

Pay attention to your fuel line routing....see my signature line below.
Your new RPM petcock will already come safety wired.

Also it's time to service your carbs. Get the RPM carb kit, thank me later.

http://www.rpmracingca.com/proddetail.asp?prod=carbkit

We have good carb info. over in the Carb Files section.

Cheers
Pat

[TobinM]

Tobin.
Your diaphragm is most likely faulty. RPM has a rebuild for reasonable. Best just rebuild it and save yourself the worry. Suggest checking your crank case for fuel contamination. Don't forget to safety wire your outlet pipe on your petcock as they have been known to fail.

Congrats on your new to you FJ.

Sweet I just got the rebuild kit and I'll see if that fixes the issue when it comes, I appreciate the help.

[TobinM]

Tobin,

You have at least two problems.  The fuel petcock needs attention, yes.  Clean, rebuild, or replace it.  Your carbs should also stop the flow of fuel, and if they do not, they need help also - clean or rebuild as necessary.

As said in the post above, leaking carbs can dump fuel directly into your crankcase, destroying the oil.  If you smell fuel at the crankcase oil filler hole (remove the oil filler plug and sniff), or if the engine oil level increases mysteriously, then DO NOT run the engine until the fuel problems are completely fixed, and you have replaced the bad engine oil with new oil. 

Fuel leaked in the engine oil can ruin your engine and transmission.

I havnt noticed my oil levels randomly going up, I am going to clean out the oil tonight and see if it's in there. I'm also going to clean the carbs soon. Thank you for the help

[TobinM]

Buy a new 84/85 petcock from RPM and be done with it. You lose that wonky reserve function, but, so be it. You already have a gas gauge, a fuel light and an odometer. Electric reserves are stupid.

http://www.rpmracingca.com/proddetail.asp?prod=M%2FC%3A36Y-24500-01

I have never had good luck with the aftermarket petcock rebuild kits.
40 years of being in a hot under tank environment takes its toll on petcocks.

Pay attention to your fuel line routing....see my signature line below.
Your new RPM petcock will already come safety wired.

Also it's time to service your carbs. Get the RPM carb kit, thank me later.

http://www.rpmracingca.com/proddetail.asp?prod=carbkit

We have good carb info. over in the Carb Files section.

Cheers
Pat

Awesome I'll look into getting the manual petcock and get rid of that wiring. I'll also look into getting my carbs rebuilt soon. Thank you

[andyoutandabout]

Yep, agree with Pat; replace with fully manual older style petcock and rejoice that you discovered this wisdom while parked at home.
Mine did the dirty way up on highway 101 and involved mercy calls to RPM and postage and packing to Oregon, but the adventure continued and all was good.