Fe501 '94 fuel tank mod

Hi!
I am building a bike based on a half-destroyed FE501, just finished repairing the frame and suspension and put in the new engine (it is a 125 two stroke). Dont worry, the original engine was total toast, a valve broke off and made some party in the cylinder finding its final resting place in the piston...

So the issue is, the new engine is higher than the original, so I had to cut out a piece from the lower right side of the fuel tank to make it fit. Two planes can be fit into the cut, making it pretty easy to seal with a correct method. A plastic welder made some tries, but could not stick it, not even with its own material. Could someone help me finding a method to weld/glue this plastic shock and fuelproof? It is a yellow Acerbis tank, feels quite soft.

I also thought of cutting some aluminum into the hole, studding or bolting it around (like repairs on airplane outer hulls) and applying some sealant into the gaps. I would not really like to do this, I dont feel it safe nor really elegant..

Szatyorfulu

Thanks for answering, I thought of that as well. Sure it could work, the Apache attack helicopter uses such fuel tanks But I think it is quite hard to 1. find some material thats fuelproof, easy to solder/weld/glue 2.make the bag fit good inside the tank 3. fix the bag inside so it cannot separate on impact after a jump or a crash 4.Make it so it can be filled through the cap.

Sooo I would not like to use that method.. any other ideas? Someone said that soldering equipment may work, has anyone done something like that?

Szatyorful

Well that sounds good, but is there an mx tank for this years (94-96 I think)? I have seen replacement small tanks but only for 2013 and on, would that also fit?
Update: would the FC series tanks fit on the FE series?

webmonstro: I have two tanks, this one was already cracked on the bottom, so I didnt hesitate to cut into it the other one is old but intact.

Taffy: I thought of repairing the original engine, but everything above the crank was badly destroyed and the money I spent on the project would still not be enough to buy more than a piston and a cylinder.. not to mention that the maintenance costs are much higher for the Berg engine(sure it rips better though ).

Szatyorful

Thank you guys for answering, you helped a lot! Im gonna get a smaller tank and no more problems

Szatyorful