Head Gasket

I have a kinetic TFR and i was wondering what the average size for the head gasket (or gasket between cyllinder head and the cyllinder it self) for any moped. Im just curious because it seemd alot smaller than i though it would be. Also what does the thiness of the gasket do in terms of performance.

Re: Head Gasket

Ron Brown /

Thinner gasket = higher compression ratio. (usually = more power)

Re: Head Gasket

What would no head gasket do?

Re: Head Gasket

As long as it didn't leak it would make more power...everywhere

top, bottom, middle.

Take the head off and look at how close the edge of the piston comes to sticking OUT of the cylinder

Then look at the head and see what the angle of the combustion chamber looks like at the edge.

You are trying to figure out if the piston woud hit the head (it probably won't)

But you should check it out first.

Then try it.

Run it for a while (15 min) and take it apart and see if you can see evidence of leakage (black soot).

If you have leakage you better put the gasket back in.

If not...check it again after another hour.

If no leak........... great !!

And make sure you tell us how it worked.

Re: Head Gasket

Ron Brown /

Many moons ago, in a far away land, on a cold winter evening, I remember watching my dad working on his BSA Winged Wheel in the kitchen.

He was applying valve lapping compound to the aluminum (actually aluminium)head and lapping it to the cast iron cylinder. He used the same method as with valves, twist back and forth a little while applying slight pressure, then lift and turn about a third of a turn, then repeat the back and forth. Do this until the mating surfaces are an even grey color. This cylinder had a liner which extended slightly into a recess in the head which was where the gasket went. This made the lapping alignment much easier. NOTE, DO NOT GET LAPPING COMPOUND ONT THE PISTON/CYLINDER WALL. Wash off the head and wipe off the cylinder top with gasoline or similar before re-assembly. You can use a very light smear of high temp gasket compound.

I think my dad gained so much power from this, that he was able to easily keep up with all the people who rode bicycles to work.

Good luck,

Ron

Good luck.

Re: Head Gasket

Thanks for all the help, i plan to check it out today and see what happens, ill put up a new post with how it goes. For Ron's comment i had a some trouble under stnading, what do you mean by lapping. Thanks for all the help, i have gained so much from this fourm.

Re: Head Gasket

Ron Brown /

Lapping is a process of rubbing two surfaces together, with an abrasive compound between them, to fit them to each other. Check for valve lapping compound at the auto parts store, it should have instructions with it.

Ron

Re: Head Gasket

I'll have to try that out. I took the head gasket out today and put it all back together. I started it up and it made a clunking sound so i qucikly shut it off. I was sure that it wasn't hiotting when i had the thing not on completly because the piston didn't even come all the way out of the cylinder when it was at TDC. Does the piston come out any further when it is started just because it is going faster, if so how much do u think Could it have been that the head wasn't tight enough, because on one side the thread on the nut was stripped and it wouldn't go on that tight, but the others were. Thanks.

Re: Head Gasket

Brandon E /

When you took the head off, did you put the spark plug back in and look at how far it came down from the lowest point on the head? Your piston was probably hitting the plug. Look for signs of contact on the top of the piston.

Re: Head Gasket

It is definetly not the spark plug that is hitting. Im going to put the head back on as soon as get some new nuts, because one is stripped. I'll update on what happens.

Re: Head Gasket

what type of moped is it? new tomos targas dont have a head gasket and they work fine. they make them that way so they have higher compression. well good luck

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