Gas Tank

[cajun31]

I had a situation where I had to come back from a "soft lay-up" of my 79 Special 8 months after walking away from it.

The ethanol gas had evaporated/condensed (leakey fuel cap gasket...) into a GOO much resembling roofing tar.

(Note: This GOO had also managed to corrode/eat through the aluminum aftermarket petcock "Plate Adapters" to leak out the tank, onto everything underneath, and leave a puddle of TAR under the bike...)

SOooo, had to get that goo outta the tank- Quart of carb dip mixed with BB's (yes...Thanks Crosman 760 Pumpmaster!) along with SS Pachinko Balls and a lot of shake-n-bake in every orientation with all holes covered with custom metal plates.

Drained and flushed with water multiple times. Afterwards, hooked my Shop Vac (output...) to the tank fill (padding round the hose) to force dry desert air and thoroughly dried like it was a lil old lady under the hairdrier at an old school beauty shop for 1/2 an hour.

Then? Saw the "limited" rust inside. My choice was to use "Ospho" a phosphoric acid that I've used many times before on other similar projects.

Did a fine job of converting the iron oxide (brown/rust) into iron phosphate (white/powder) and after a secondand third water/rinse and blow dry with the shop vac? Nuthin' left but the shiny metal plus the black areas (under the iron phosphate) where the rust process had been "arrested."

(Note: I prob'ly should made video's of this as I didn't just trust my Mark 0/0 Eyeballs. Used a borescope/camera to peek/poke all around the inside.)

Only negative side-effect? I had everything removed EXCEPT the Special Fuel level sensor plus the plate holding it in. After reassembly (plus 3 weeks...) fuel started leaking out from around the wire passing through that plate.

Fixed(?) by removing the plate and the sensor wire, blocking off the wire passage thru the plate, and re-installing the plate with a new gasket. ( Now without the factory "low fuel" indicator system.)


Might have avoided this if I had removed the plate/fuel level system at the beginning... ¯\_ʘᗜʘ_/¯

Take-a-way? (´._.`)

Ospho (phosphoric acid) worked fairly well and the fuel sensor leak/loss is MY bad for not removing it.
(º～º)

Apple cider vinegar is strong enough to arrest the rust, yet not strong enough to cause damage to those parts or the paint finish. Takes a bit longer to work but does a great job at cleaning the tank.

[LAB3]

Something I've seen pop up in this thread and others in the past is the use of Apple Cider Vinegar, my understanding is that vinegar is used for the acids it contains. It seems to me that for half (or more) of the same cost that plain white vinegar does the exact same job. Maybe someone can fill me in on what I might be missing.

[bikerphil]

Fuel Tank Sending Unit Gasket....

https://www.partshark.com/oemparts/p...et-sender-unit

[cajun31]

Larry. Thanks for the insite.

Got me to thinking. I should replace the gasket for the fuel level sensor while I’m at it. But I don’t remember seeing a new one available on the web. Did you find a resource for one.

once again. What a great community, where ideas and experiences are shared. Jeff

The part number you are looking for is 2H7-85753-00-00. It is the same gasket for both the early and late model bikes. Here is a listing for it on Ebay. YAMAHA OEM Sender Unit Gasket 2H7-85753-00-00 1978-1993 XVZ13 FZ750 XZ550 + | eBay

[cajun31]

Something I've seen pop up in this thread and others in the past is the use of Apple Cider Vinegar, my understanding is that vinegar is used for the acids it contains. It seems to me that for half (or more) of the same cost that plain white vinegar does the exact same job. Maybe someone can fill me in on what I might be missing.

They are both effective. The white is just slightly stronger and you have to pay more attention when using it. Over the years the cost of the apple cider vinegar has gone up more then the white vinegar, so I suppose that would be something to consider. I have always used the apple cider version because I know for sure it is milder and can be left unattended for longer periods without the risk of damaging anything.

[Larrym]

Larry. Thanks for the insite.

Got me to thinking. I should replace the gasket for the fuel level sensor while I’m at it. But I don’t remember seeing a new one available on the web. Did you find a resource for one.

once again. What a great community, where ideas and experiences are shared. Jeff

New gasket? Got mine from Partzilla- Ordered on Jan 5, 2024. This year! (O_O)

https://www.partzilla.com/product/ya...H7-85753-00-00

($18.33 fOaR the gasket but all together to-my door costs-$28.99)

Obviously available elsewhere's too, according to bikerphil-n-cajun31. ( ´⌣`ʃƪ)

Imma more than amazed that this gasket is available at ALL. I mean if it wasn't? Any good mechanic would get out the gasket paper and have a go at the DIY version but really only cuz there wasn't any other option. Very surprised to have found it. (; ꒪ö꒪)

Pretty cool that even though the Standards and Specials tanks are SO different, the engineers manages to use the very same gasket across both types. ヾ(⌐■_■)/

BUT...even mOaR amazed at how difficult it was to actually FIND. NOT listed where you or I or anybody would look for it in the Fuel system parts list or exploded diagrams. (º～º)

ELECTRICAL section. Like...D'uh. (－‸ ლ)