I have a Super Tigre 45 that keeps blowing the gasket out between the muffler and the head. After the gasket blows the screws holding the muffler vibrate out and the muffler falls off. I'm running the motor on Sig 10 %nitro fuel. Any idea how to stop the gasket from blowing out or what maybe causing the gasket to blow?

TiggerFlyer :drowning:

I love the smell of nitro in the morning

I stopped using those gaskets years ago.....not only do they blow out easily, but they also contribute to the header coming loose....
You have two good options. I have used an automotive product called RTV Blue as a gasket material or I have had good luck with epoxy. Great engine
Best
Brian

Don't put a gasket in there! The Super Tiger Gasket only lasts about 10 seconds in spite of it being made from Kevlar gasket material.

Clean up the mating surfaces real good and slap it togehter with some lock washers on the screws. You may use a thin layer of the red high temp silicone on the joint if you want to but most people run with nothing in the joint. Some others have made aluminum gaskets from pop cans. You can cut them out with a pocket knife and punch the holes with an ice pick or awl.

Enjoy

Jim

I have never used their gasket or any gasket material between the muffler and exhaust outlet. I bolt the thing down tightly and if I ever have to remove the header I replace the lock washers.

i have a problem with my piston.   i have a brand new 45   i was breaking in the engine on the bench when it flew off the bench and hit the ground  breaking my new prop and doing something to the engine.    i picked it up and checked it out.   i noticed that it was turning over but very hard.    i disassembled it and noticed that the cylinder was loose in the housing.   and i also noticed that the piston would get stuck about 3/4 of the way up the sleeve.     i was hoping that someone could tell how it coming off the bench could make this kind of problem

You have a ABC engine. That is normal for a ABC engine. The cylinder sleeve is tapered towards the top, the piston will have a tight pinch like effect as you move it towards the top. Now when the engine is running and all warmed up good, the tapered part expands and the cylinder is straight. So the piston will move up and down with a just right fit.
You do need to get the cylinder aligned inside the crankcase just right or you'll lose power.

Well, for one - how or why did it come off the bench? Second - something probably got bent or damaged upon impact. Bent crank or damaged engine casting are within the realm of possibility.

Its not normal for the engine to come flying off the bench and hit the ground though.

this was the first start up on this engine and   after this incident   it is 5  times harder to turn over then what it was before this and it is now making a loud creeking sound.</p>

i was being a retard  and i should of known that putting it in a vise was not going to be good enough.

I think you might have wrecked the engine, to be honest. Something is bend or crushed or something of that nature.

Oh dude.... <shakes head> I'm sorry - but that was not a good idea. Most instruction books say not to use a vice because a) they can come loose and cause the problem you have (having it fly off the bench) and b) can actually distort the block causing issues.. Both of these things could be in play here. Take it apart and look at it. Roll the crank on a piece of glass, same with piston and sleeve.. see if anything is bent. If not, The block might be damaged... (I'm no expert but that sounds like a logical place to start)

i have noticed that the piston gets stuck in the sleeve about 3/4 of the way up.   and i mean stuck.

I'd take it apart and evaluate the internals as well as the outside of the case. What part of the engine hit the ground? If the head or top of the engine hit with enough force it could have warped or distorted the case off-center causing the cylinder to be "bent" and having the piston get stuck. It could also be a bent crank pin too?

If the engine was running when it hit the ground, you could have a bent crank, a bent rod, or a bent/distorted something else. If you remove the piston/cylinder assembly from the engine and the crank will turn smoothly and the piston moves up and down the liner smoothly, you have a bent rod. Careful checking will tell you the exact difficulty.