Plastic Gas Tank

[AppleJack]

Good Morning All,

1985 FJ1100  Sat for 5-6 years.  What is the tank actually made of?  Fiberglass, plastic of some kind?  Other?

What should the inside of the gas tank look like?  This one is a yellowish, kind of bumpy/uneven surface. Is it even safe to put gas in again after sitting so long?  Slides in the carbs were completely stuck in place.  What can I do to safely recondition the inside of this tank? Is there a fuel filter somewhere on the bike?

Can I simply rinse out with gas and try it again?  I was hoping someone else had had this same problem and a solution, too!

Thanks, Jon

[Urban_Legend]

Hi Jon

The tanks are steel. The yellow gunky stuff is most likely old dried fuel. The carb will most likely need to be pulled down and given a really good clean. (Ultra sonic and elbow grease)  not sure what to clean the tank out with. The fuel filter for these early fj's is in the tank attached to the fuel tap. Ihear a lot of our American FJers talk of putting sea foam (not sure, we dont have this product in Australia) in thier tanks to clean out the gunk.

Mark

[FeralRdr]

My guess is it's some sort of tank liner product such as Kreem or Por-15, especially if it is covering the entire inner surface of the tank.  If it were old fuel, it would probably only cover the areas of the tank that were submerged in the fuel.  The parts of the tank above the 'fuel' line should still have a 'metallic' appearance (assuming no corrosion issues).

[AppleJack]

Yeah, I have carbs off and cleaned - will need parts (o-rings, main jets)  from RPM before reassembly however. 

Here are a couple photos down the filler hole.  It's metal then?  Hmmm 

And I did get a chance to take the petcock apart, diaphragm/seals looked good, so I simply cleaned it all up and stuck it back together.  Part of the silk screen filter element is torn away, but it should be okay after I safety wire it.  Phew, that should save a couple hundred dollars!!

Anyway, maybe some Sea Foam is the answer, it's readily available here...

Thanks anyway

[AppleJack]

"Nother Photo

[FjLee]

Yeah, I have carbs off and cleaned -  

And I did get a chance to take the petcock apart, diaphragm/seals looked good, so I simply cleaned it all up and stuck it back together. 
Thanks anyway

So you got the  carbs and petcock  all clean now.  Correct??

Ummmmm......Dude........you might see if someone will hold your beer while you get a second and third opinion on
that fuel tank interior.

FjLee        84 FJ1100              Denver CO

[movenon]

That tank has been sealed.  Not all bad or good.  I would recommend that you flush out the tank as good as you can with some gas, pull the petcock and check / clean the screen, rebuild the carbs and see how she runs.  Fuel filters are not recommended in the old gravity feed FJ's but in your case I might say run a filter for a while and see how it looks after a trip or two.  If clean then remove the filter and press on.

The FJ tanks are a bitch to get clean. To many areas you can't see or get to.  Don't go down that road unless you have to.

When you say jets I hope you got new pilot jets.  Also recommend you pull the emulsion tubes out inspect and clean.

Heads up when you put it back together route the fuel delivery hose EXACTLY as spec'd by Yamaha.  As you will probably have or leave a fuel filter in the line you can expect that full throttle runs might starve out on fuel, just expect it as the gravity feed FJ's just don't have enough head pressure and it gets worse as fuel level go's down.

Just some thoughts and opinion's.
George

[AppleJack]

Yep, carbs are all cleaned using Berryman's Chem Dip.  Spray carb cleaner comes out of every place it's supposed to when I squirt it in.  Broke two main jets removing them - is 120 the standard main jet, as that's what's in this machine?  Service manual says different?  Stock 4/2 exhaust / air filter.

I'll be replacing all o-rings once I get an order put together.  Those on the fuel "t" fittings between carbs especially bad. 

Still very worried about running gas out of that tank.  Anyone have a spare in a little better condition? 

Will also need new clutch slave cylinder as it's froze up - even compressed air will not get it out!  One thing at a time, eh?

And still need to address front brakes, too - pulling the brake lever does nothing - same as the clutch lever.    Found my old snap ring pliers so I'll be taking a look at both master cylinders tomorrow...

'Til then and thanks for all the suggestions...

[FJmonkey]

Still very worried about running gas out of that tank.  Anyone have a spare in a little better condition? 

I have a spare tank but I think it is an '89+ and has some repairs. It has the interior coated (rough looking) and other patches so buyer be ware... I can photo all visible issues if interested. $60 USD + shipping.

[AppleJack]

So, I'm new to this Yamaha ownership thing, what would cause you to dump this coating/sealer into the tank?  Something I'm missing here.   

Not wanting to do anything sacrilegious here hehe, but I had a GS1000 Suzuki for over 20 years and never saw the need to do anything of the sort.  Design flaw?  Poor seam weld?  Understand this was exacerbated by leaving it sit for so long, too. 

I've already swished around some gas in there, need a couple of fuel filters I guess. 

[FeralRdr]

So, I'm new to this Yamaha ownership thing, what would cause you to dump this coating/sealer into the tank?  Something I'm missing here.   

Not wanting to do anything sacrilegious here hehe, but I had a GS1000 Suzuki for over 20 years and never saw the need to do anything of the sort.  Design flaw?  Poor seam weld?  Understand this was exacerbated by leaving it sit for so long, too. 

I've already swished around some gas in there, need a couple of fuel filters I guess. 

Sealer is typically used when the tank has corrosion issues.  Looking at the rim of your fuel filler port (last pict), raises concerns with me as it appears that there is a lot of corrosion in that area.  If the tank wasn't properly prepped (meaning absolutely cleaned of rust), the lining will eventually start to peal or flake off.  If the particles are small enough, they can get sucked into and clog the carbs up.  Since you have a gravity fed system, fuel filters really won't work for you.  Quite the contrary, they typically cause fuel starvation issues as there's not enough fuel pressure in the gravity feed systems to fully overcome the restriction of the fuel filter.  To be clear, the fuel filter won't stop the flow of fuel, but it will reduce the flow of fuel to the point that under hard acceleration, or long term high speed riding, you will start to encounter problems, as the fuel level in the float bowls starts to drop.

[mr blackstock]

G'day,

I watched a video awhile ago about a bloke who filled the tank with nuts and bolts, jacked up the rear of the car, and strapped the tank very well to the rear car wheel, started the car and put her in 2nd or 3rd gear for around 10 minutes.  After all that he stopped the car, unstrapped the tank and the inside was so clean!

Here is a link to the same idea:
https://www.youtube.com/watch?v=i7I1O0K7EF8
https://www.youtube.com/watch?v=GotZz4oDt9k

I'm serious too!

cheers, Gareth

[the fan]

A guy local to me did something similar but used a rented concrete mixer to spin the tank.

I have no idea what could be used to strip the coating off that would not risk destroying the paint.  Yamahas are no more prone to tank rust than any other make.