23 year old tank with gas still in it...gas cap stuck! (Solved!)

[mikerophone]

A few more shots

A few more shots

Here's a shot of the nasty brown gas:



And some more of the sending unit scraping with a flat blade wasn't proving real productive, that's when I went to get the soda blaster:



Still needs another once over, but here is a shot after a quick soda blast:



And here's how the inside of the tank looks before the vinegar soak - there is metal under all that rust:



And while I was getting my soda blast on, I hit the carbs bodies on my other 850. I'll be putting up a separate post of the strip, dip and sonic clean of these:

 

[Brendan W]

Persistence pays. Thought for one minute I was looking at some marine archeology forum. I hope I remember this thread the next time I start to lose patience.

 

[chuck hahn]

There are 3 little tabs bent over that hold the cover on the sending unit. Bend them up and this allows access to the waffle board and contacts inside for cleaning. If the tabs break just use wire and go around the cover to hold it back in place. The internals will need a good cleaning also.

 

[mikerophone]

Persistence pays. Thought for one minute I was looking at some marine archeology forum. I hope I remember this thread the next time I start to lose patience.

Indeed it does, as does the great help from the forum once again!

There are 3 little tabs bent over that hold the cover on the sending unit. Bend them up and this allows access to the waffle board and contacts inside for cleaning. If the tabs break just use wire and go around the cover to hold it back in place. The internals will need a good cleaning also.

Thought about bending those open when I had it out, it's soaking in the vinegar filled tank right now, but I will pop it out and open and clean the contact - thanks Chuck!!

It's looking pretty good in there this morning - lots of loose rust dislodged in the vinegar:



Here's the before:



And the after - the vinegar does a great job, those were screws after all, not some marine algae encrusted wreckage:



Going to let it soak a few more days, then I'll clean the contacts in the sending unit box and probably take it to the laundromat depending on how it looks.

 

[Brendan W]

Just looking at what looks like severe pitting on one of the ears under the cap. It might be fair to assume that the internals are in a similar state and close to total failure if something lets go. I would certainly like a closer look at what's going on inside the cap.

 

[JTGS850GL]

I'd be concerned, with that much rust, that some of the pitting in the tank will eventually begin to leak. I'd do an internal coating as a minimum. Do a real good inspection for rust bubbles un the underside of the tank. Especially along any seam lines. The rubber seal on that cap is in pretty bad shape as well.

Personally I'd be looking for a newer tank, petcock, and cap. Sending unit can't be in great shape either.

 

[mikerophone]

Just looking at what looks like severe pitting on one of the ears under the cap. It might be fair to assume that the internals are in a similar state and close to total failure if something lets go. I would certainly like a closer look at what's going on inside the cap.

Thanks Brendan, there was a crusted gel/varnish type material that definitely eroded some of the soft aluminum ears as I scraped it off and it's much more apparent now that it's clean. The top face/edge that contacts the underside of the flange is in better shape but I'll surely keep an eye on it. I've never opened up a cap, is there more aluminum inside? The steel elements seem pretty intact other than surface rust throughout.

Worst case, I have a spare cap that I could swap the key cylinder over to, but chances are I'll be cleaning this bike up, swapping this 12k 850L engine over into my 50k 850G frame and vice versa then selling this L bike once I go through it. We'll see. I have to sell either this L or my trusty old v45 Magna, I don't need 4 possible daily riders. 3 is more than enough... nthego:

Good catch either way. I'll take the cap apart Sunday and get a better look inside. Any special things to watch for like flying springs upon opening that you know of?

 

[mikerophone]

I'd be concerned, with that much rust, that some of the pitting in the tank will eventually begin to leak. I'd do an internal coating as a minimum. Do a real good inspection for rust bubbles un the underside of the tank. Especially along any seam lines.

Personally I'd be looking for a newer tank, petcock, and cap. Sending unit can't be in great shape either.

Thanks JT, seams look good, from the outside anyway, wish I had an inspection camera. I'm considering a POR-15 coat or the Eastwood version but if I flip this bike, I'll just mention the concern to the buyer and let them decide. I don't want to end upside down on this. I got a good deal but not a great one, most of my investment between now and then will be cleaning, polishing and testing electrical to make sure it's a solid runner. I will likely have to do the R/R and have to find a headlight and front signals as well, this bike came with an old Pacifico fairing - I'll be posting up a thread on it when I pick it up next week and start the cleaning process but it'll be slow, have 2 motor swaps to do in my truck and daughters SUV, plus I have to move this motor over to my G like I mentioned in the thread were you commented about the G and L engines and shafts being the same other than the ignition... Got my work cut out for me and it's not even spring yet!

 

[Brendan W]

Good catch either way. I'll take the cap apart Sunday and get a better look inside. Any special things to watch for like flying springs upon opening that you know of?

Haven't opened one of those but.......... there are always flying springs

 

[chuck hahn]

Heres the skinny on the cap.

Take the two screws off and remove the plastic cap. The latches will come off with the cap There is a spring that forces the two halves apart when you remove the key and make the latches extend and latch the cap closed. That spring usually doesnt come out easily but remove the cap slowly in case.

Next youll see a kidney bean shaped plastic deal with a screw at each end..has a big ball bearing in there. Remove the plastic cap and observe the ball bearing sits on a metal cup thing. Just note the order so it goes back the same way.

Now youll see the oring that seals the lock cylinder so gas doesnt come out the key hole..its gonna need replaced so take it out. now if you out the key in youll see the bottom of the lock cylinder turns under there. Look and youll see a retainer about 3/16 inch wide that holds the lock cylinder in. Get a utility knife blade and depress that retainer in and apply a little pressure to the bottom of the cylinder at the same time. The lock cylinder will slide up a tad. At this point you can push the lock cylinder out the top of the cap. NOTE::::: The waffers are spring loaded and wont ..or should I say "shouldnt" come flying out. But be gentle and you can use some carb cleaner and a tooth brush to GENTLY clean the cylinder. To reinsert the cylinder simply depress the bottom retainer and get it past the rim of the cap and slide it in and it will click itself back in.

The cap vent is actually a channel milled in to the base metal and is covered by the chrome cap bezel. Once its all apart soak the cap in carb dip or vinegar overnight to eat the rust and debris from the venting channel. If you look at the bottom of the cap where you took off the kidney beak shaped cap and ball bearing youll see a hole in the base metal...this is the vent hole. Blow compressed air into that hole and the crud inside the channel will come out around the outer edges of the chromed beauty cap. Some carb spray a few times and air will ensure the venting channel is clear.

 

[chuck hahn]

Just saw the cap seal...man she is shot!!! So when you have the black cover off the seal will pry off the seat. Youll see that the seal is affixed to a thin 4 sectioned metal plate. I would get some thick neoprene and fuel proof glue and make a new seal.

And note that there are a lot of aftermarket caps from China on Ebay that are cheap and pretty darn good cosmetically to the OEM ones. May be worth the 20 bucks or so to just buy a new one.

 

[mikerophone]

Wow Chuck - you are a wealth of knowledge and help! Thanks so much, think I'll carefully follow your instructions and see if I can't get it apart and cleaned nicely and the seal replaced otherwise maybe I'll order one of the cheap eBay ones wondering if my key cylinder would fit into one of those however...

 

[chuck hahn]

It should fit ok. Ive taken many many caps apart for servicing after "unknown" amounts of time sitting around. I had an old rusty cover that wasnt worth the effort to even soak and was curious as to how it vented and pried the crimp up and took off the chrome cover and discovered the venting channel and just followed it to the tank end..thats how I learned.

 

[mikerophone]

Awesome - good to know, thanks again Master Chuck!

 

[chuck hahn]

I should add this...If you have the key in the cylinder it will stop the waffers from being able to come out o the cylinder itself. Take the cylinder out and then put the key in it.