81 xj550 project

Have you inspected the tank to rule out a pinhole in the tank?

 

That's what I thought at first too but the area where the leak happens seems solid

 

Actually... I think you might be right and I must have missed it. Just checked the pic that I too and there appears to be a tiny hole.
Never noticed before.

 

Bottom left. No idea how I missed that.
Poop. Another item on my list.

 

Glad that you found it. Those can be really difficult to trace. Gas can run to that point form much further away.

 

I am really grateful for the tip. I would have never thought to look for that and it would have driven me insane. It never formed a drop. I checked that area three times looking for some sort of drop formation.
Next question is how to fix it.

 

My prefrence with that small of a hole is to braze it shut, but you have some nice new paint there and that may be a problem if you don't have a pencil-tip torch and good heat control. Loctite and Permatex both make a fuelproof two-part epoxy that should fit the bill.
The only other method I can think of is to fill it with plumbing solder, and in that case you can use a high-watttage electric soldering iron, or heat up a peice of stock with a torch. The soldering takes some skill though, and just as much prep work as the other two methods.

Now, for the real issue. How rusted is the inside of the tank? It may be worth your while to just line the tank as a preventative measure. Caswell sells a fantastic kit for just such a situation, but it is the more costly solution.

 

Great, thanks.
Another thing learned for next time.
Category "things to check"

Just saw the last part. Tank has liner in it from previous owner. And from what I can see, it looked good. But then again, I can only see so much when looking through the gas cap. Didn't think of using any dentist mirrors.

I will look into caswell but I would prefer not to line. I did it once and the result was not that great. I remember it was red stuff which colored the fuel.

 

Dropped off my carbs to get the float height set. I figured it would be easier and better for my health. They are ready for pickup.
I also ordered new bolts for the airbox/intake clamps. The old ones were worn out.
Weather for the long weekend looks promising too.
Fingers crossed...

 

Confirm the fuel levels when you pick up. Ask if they wet-set or dry-set the floats. Dry set gets you close; wet-set is the standard called for.

 

Will do. It sounded like he wet set them because he noticed one needle had some play and gas was leaking. It is fixed now.
There was some background noise so I did not hear the details. I will ask him tomorrow when I pick them up.

 

Hello,

So, carbs are back in bike. Haven't started it yet, it's too early in the morning and I don't want to wake anyone up.
Apparently I have another leak in the tank. I jacked up the end where the petcock sits to leat the sealant cure. Had fuel inside which has been leaking a bit for a week now. The right front corner started to bubble. Grrrrr. Not super huge area but it annous me. Looks like the tank will go back for touch ups at some point. And I guess I might as well apply sealer before I drop it off.

Anyway, reason I am writing: I have a vacuum petcock, but I am not fully sure I understand what's going on. I thought I did, guess not.
Tank is off the bike. On prime, fuel just runs. In the on position, nothing happens, even when I suck on the vacuum hose.
On reserve, nothing happens unless I suck on the vacuum hose.
I thought, for whatever reason, that "on" should make the fuel flow with vacuum as well? And that's the setting the petcock should be on at all times (only allow fuel to flow when bike is on)?

I dont mind leaving it on "reserve" at all times to get the result, but am I wrong or is the petcock behaving silly?

 

I just reached out to two bike shops who are mentioned on the caswell site and who work with caswell tank sealer products. Think I'll just ship it out, hopefully they can touch up the paint as well.
The tank must have been coated before from the looks and I don't want to do it myself in case the existing coat ruins the new sealer.
Got to a point where I rather have a pro do it quick and clean vs me on trial and error.

 

Your petcock is behaving silly. Since you get fuel flow in the reserve position with vacuum applied I think that you need to take the selector lever off and look for an obstruction, or a misaligned gasket.

Petcock Rebuild

 

Thanks for confirming.
Hmm,it's a band new petcock. Grrrr.
I'll do it when the tank is shipped out and getting the touch up.

 

At least I'm pretty sure now what I am going to call the bike: Major PITA

 

Welcome to the world of classic bikes. Look on the bright side; you are working on a machine that has good parts availability, and well documented service procedures.

 

Very true. And I didn't have to do anything to engine yet

 

I just rode around the block a few times.
Oh man... I am sooooooo happy.

After float adjustment, the bike sounded different too.

This was so much fun....

 

Wondering what the ratio of the speedometer is..? I am looking at getting a new one for my 81 Maxim 550 for my build and I wasnt sure if its a 2:1 or a 1:1 ratio... Thanks
Matt