Please advice with(plastic) gas tank. Leakage, damage, repair.

[kokis]

Mechanic for some reason drilled out bolts (I guess it was bolts) to detach gas pump. Somehow he damaged gas tank where pump attaches to it. He fixed it with some germetics and it was ok while bike was not in use. But in 1 hour of usage it started to leak.
I returned it to him to fix again, and he said that he did not test it under pressure and he did not gave it time to stick\crystalise blah blah. I don't believe him anymore, I think he is an idiot. Is there any pressure in tank? I think no.
What is my perspectives?  Is there anyway leak in plastic tank can be repaired properly?
Reason I am asking is because I read that there is no proper germetic that will stick to plastic and will still flexible \protected from vibration and heat from exhaust pipe.

[ducpainter]

I'd make him replace it.

There are epoxies that might work, but for how long would be the question.

[DarkMonster620]

I'd make him replace it.

There are epoxies that might work, but for how long would be the question.

+1000 what he said . . . and I made more obvious

[kokis]

Ok, I got to the mechanic to see what the hell he is doing. I found out that there is nothing criminal, I was wrong about him, he did not drilled anything that has structural usage.
Leakage was because rubber spacer between tank and pump mount was loose. He made new from special rubber   and now it is fine.

Case closed.

[kokis]

Well case not closed
Tank is not leaking when it in use now. But leaks when it stays on sun and heat creates pressure in the tank.

The problem is that nuts that molded into tank  that used to attach pump to it, some of them come out when tighten it. So O-ring and rubber won't help.
How to fix nuts in tank?

[ducpainter]

Replace the tank.

[SpikeC]

 Vent the tank. Also.

[kokis]

Replace the tank.

It is Russia... Russians do not replace parts if they have hammer and ducktape in possession.



Looks like there is no way to fix them securely.

Mechanic will make new screw-like nuts and will screw them in there.

[ducpainter]

It is Russia... Russians do not replace parts if they have hammer and ducktape in possession.



Looks like there is no way to fix them securely.

Mechanic will make new screw-like nuts and will screw them in there.

A hammer is my go to tool as well, but in this circumstance it won't work.

Not knowing what you have available for materials makes it difficult to recommend a fix.

[kokis]

I can find most materials.

[ducpainter]

First of all, your mechanic damaged that tank by making a gasket that was too thick, and over tightening the bolts, which made the inserts pull out of the plastic, or by heating the bolts to remove them and melting the bond between the insert and the plastic.

It's fine to be frugal, but every once in a while there is some engineering involved, and while most engineers think they are the master of the hammer they are as wrong as your mechanic thinking he can engineer a part.

I think I'd try removing the inserts from the tank, shortening them by machining, and then try to reinsert them in the holes and use some jb weld (read the directions) to hold them in like the molded plastic did originally.

Don't let him use any kind of screw into the bare plastic. That won't work any better than the hammer or duct tape.

[kokis]

Will post tomorrow how we managed this . Not sure jb weld will stick to plastic good enough, even another melted piece of Polyethylene don't stick to this xlPE(checked with couple different masters who work with cracked\broken autoplastic parts)

[ducpainter]

What kind of bike is this?

Most Duc tanks are PA6 nylon...not PEX.

[kokis]

It is 696.

[ducpainter]

It is 696.

They won't let them use PEX for gas tanks here.