anything specific to check before I get in the wind?

[RPM - Robert]

No. They were discontinued sometime last year and we sold the last one a few months ago. The 84-85 can be used in its place as dimensionally they are the same. You lose the reserve function by swapping to the 1100 petcock but you do gain a manual prime & on function.

[FJmonkey]

I put an 84' petcock on my 86' when it failed the SUCK test. The Prime function is nice to have.

[Pat Conlon]

The prime function got me home....

[Troyskie]

Same for me.

I just recently had a petcock issue on my 86. Just as for Mark, the petcock failed the suck test.
I had a spare 84-85 on the shelf and haven't looked back.

Fwiw, I have ignored the 86 'reserve' switch for most of the time, and simply leave it on res. I get my refueling reminder when the fuel light begins its low glow, but generally have the next fuel stop planned to suit (I said 'generally'... ).

I've tried rebuilding these little beasties to no avail. I do admit to being a ham fisted novice. The parts are so fine and sensitive it is easy to bugger it up (I did!).

Pat once gave me some advice, if you need one, get a spare, put it on the shelf, and in the years to come it will come in handy. Also, I wonder how long the 84 petcock will be available? Might be time to top up my spares inventory  .

Troyskie

[5speed]

what is this manual prime thing you speak of?
Mine wasn't leaking and I can't pull the elbow out so I'm going to go with the safety wire but I'll keep the one for an 1100 in mind.

[RPM - Robert]

Prime allows you to fill the carburetors without cranking the bike as there is no need for vacuum. By bypassing the vacuum function you can use the prime to get home if you have a diaphragm problem in the petcock or the vacuum line fails for some reason.

Troyskie,

The 1100 petcock has also been discontinued. So when the shelves are empty there are no more. At last look at our inventory we have somewhere around 100 left but they are selling quicker as people are using them in place of the 86-87 petcock. So far this year we have sold 47 from Jan 1 until now. At that rate mid year next year they will be all gone.

[5speed]

Prime allows you to fill the carburetors without cranking the bike as there is no need for vacuum. By bypassing the vacuum function you can use the prime to get home if you have a diaphragm problem in the petcock or the vacuum line fails for some reason.

excuse my ignorance of vacuum operated petcocks..my experience is strictly with honda style run of the mill ones but how does that work? You can't even see the petcock without pulling the tank..

and to add to the "how did the bike even run with a huge vacuum leak" saga....this is the first plug I pulled out of it..



but wait..there is more..this is the type of plug and heat range they were running..
a champion.

[FJmonkey]

The vacuum petcock will close and stop fuel flow if the engine stops (no vacuum). Useful during a tip over/crash, less fuel leaking out.

[RPM - Robert]

Pop the seat and side cover off reach hand in and turn.

[red]

should I be concerned that the elbow spins in the petcock housing?

5speed,

Yes, that rotating elbow fitting will certainly leak gasoline, and that is a very dangerous defect with your petcock.  If you are not going to buy a new petcock, pull out the elbow fitting and clean out the old sealant. Then re-install the elbow with JB-Weld (or better) epoxy.  Get the angle of the elbow fitting correct then, because no changes are possible after the epoxy sets.

The petcock PRIME function lets fuel flow with no engine vacuum.  The ON function lets fuel flow only when there is vacuum from the engine (which is normal operation and a real safety feature, because the fuel flow stops if the engine cuts off, as in a wreck).  OFF just means no fuel flow at all.

If you use your mouth to pull and hold a vacuum on the petcock vacuum line, fuel will flow when the petcock is ON.  If the fuel flow stops, then the vacuum diaphragm of the petcock is punctured, and needs to be replaced.   This is the SUCK test that you may hear being discussed here.
.

[krusty]

Prime allows you to fill the carburetors without cranking the bike as there is no need for vacuum. By bypassing the vacuum function you can use the prime to get home if you have a diaphragm problem in the petcock or the vacuum line fails for some reason.

excuse my ignorance of vacuum operated petcocks..my experience is strictly with honda style run of the mill ones but how does that work? You can't even see the petcock without pulling the tank..

and to add to the "how did the bike even run with a huge vacuum leak" saga....this is the first plug I pulled out of it..



but wait..there is more..this is the type of plug and heat range they were running..
a champion.

According to my NGK catalog that is the correct heat range. Equivalent to DPR8EA-9 which is FJ1100. The FJ1200 does not have the "R" which indicates it is a resistance plug.

[5speed]

Yes, that rotating elbow fitting will certainly leak gasoline, and that is a very dangerous defect with your petcock.  If you are not going to buy a new petcock, pull out the elbow fitting and clean out the old sealant. Then re-install the elbow with JB-Weld (or better) epoxy.  Get the angle of the elbow fitting correct then, because no changes are possible after the epoxy sets.

The petcock PRIME function lets fuel flow with no engine vacuum.  The ON function lets fuel flow only when there is vacuum from the engine (which is normal operation and a real safety feature, because the fuel flow stops if the engine cuts off, as in a wreck).  OFF just means no fuel flow at all.

If you use your mouth to pull and hold a vacuum on the petcock vacuum line, fuel will flow when the petcock is ON.  If the fuel flow stops, then the vacuum diaphragm of the petcock is punctured, and needs to be replaced.   This is the SUCK test that you may hear being discussed here.
.

Thanks. that was my plan. Or what I was going to attempt. I ordered the rebuild kit from RPM so I'll do that when the kit arrives. I'm one of those "try and keep it original" guys..and ya..it's bit me in the ass before and no doubt it will again.

[5speed]

According to my NGK catalog that is the correct heat range. Equivalent to DPR8EA-9 which is FJ1100. The FJ1200 does not have the "R" which indicates it is a resistance plug.

I cross referenced it and came up with DCPR8E1X..so the heat range is correct but it isn't what yamaha recommends so I picked up new DRP8EA-9 plugs today along with new fuel line and hose clamps for a fuel injected line. those factory "clamps" look like a failure waiting to happen.

[FJ_Hooligan]

I'm one of those "try and keep it original" guys..and ya..it's bit me in the ass before and no doubt it will again.

Do yourself a BIG favor and get over that mentality.  There are a lot of upgrades that turn the FJ into a much better motorcycle.  Particularly suspension and wheels.  And they won't detract from the stock look at all.

[FJ_Hooligan]

Fwiw, I have ignored the 86 'reserve' switch for most of the time, and simply leave it on res. I get my refueling reminder when the fuel light begins its low glow, but generally have the next fuel stop planned to suit (I said 'generally'... ).

I typically get my refueling reminder from my bladder which fills up much faster than the tank empties