Gaskets - material? temperatures? thickness?

[ryerye]

I just bought a kit, and removed various parts to check if everything is ok. Next thing you know, I have the entire engine disassembled, which turned out to be a good idea, because I discovered a crack in the bearing housing? - Whatever you call it, the part in the crank-case that holds the bearings... the seller is sending me a new half of a crank case - cool. So I recommend: disassemble every new engine, make sure everything is ok, and carefully remove the paint in the 4 bearing housings - as well as removing all the other paint where there really shouldn't be any. Tape high grit wet sandpaper to a glass table and push the part along...
Now to my question... the supplied gaskets are bad. and possibly damaged from disassembly. What should I use to improve everything?

>> In summary I'm trying to gather Information on material, temperature range and thickness of the various gaskets. <<

- The clutch case and magneto case are made from what, paper?... uh, no thanks... but I don't believe they are that important, so I might just use whatever I find in the autoparts/hardware store. It only has to keep water out, probably doesn't have to withstand high temperatures and the width doesn't matter. (BTW if you have pedal clearance issues, take a close look at these covers. I would be able to remove nearly 5 mm on all of them before hitting anything, without shortening the shafts. careful with the clutch though, that guy moves outwards)

- Exhaust gasket I found this ...might look into that. (tl/d...w?: '2002 Toyota Highlander O2 Gasket' sort of fits)

- Intake: So this is actually my second attempt, I moved and was unable to take my first engine. but last time the casting for the intake was so bad, it didn't seal with the carburetor no matter what I did. It was my first time working with a two stroke (or engine for that matter) so it took me days to figure out the culprit. I then wrapped up the intake manifold? with teflon tape. which worked... the engine ran for the first time, but was soon dissolved by the gasoline. Then I used tinfoil - poor solution, but it worked, and I figured I should replace the manifold anyway. This time I received a much better casting, but I'm still considering to place a ring between the manifold and the carb. especially since I surfaced the manifold a little, and might take off some more.
cylinder to manifold actually doesn't look half bad, but does anybody know what that material it is? what temperatures it has to withstand?

- Crank case. that's the big question mark for me... Is that paper-thin-rubber? I mean I felt like they might as well have used tin foil... would be easier to punch out.
I surfaced one half (the not broken one, drive/magneto side) no problem, but I'm not sure how to go about surfacing the other half (when it arrives), since it has a lip. tape sandpaper to the good side and rub them against each other? and what material will cope with the soot, gas and oil at higher temps?

- Crank case to cylinder: Since I surfaced everything. I might have to experiment with the thickness of this one to bring everything back to normal. Also considering that bolting down the head will compress, and lower the cylinder - on that note: are there good reference-points that I can adjust from? I.e. I bolt the cylinder down to x.x Nm, put the piston to tdc and should have it flush with the cylinder or the head gasket or x mm from port y... etc

- head gasket: copper... original was 1 mm aluminium. I think I'm gonna buy various sheets of copper, to be able to make further adjustments. any other recommendations?

ok... I think that's all the gaskets. Can't wait to hear your thoughts. Thank you in advance

 

[Spare_Parts]

Intake, case, side covers and base gaskets can all be made from paper board like a ceral box. Just soak them with 2 stroke oil.

I use the Toyota o2 sensor gasket for the exhaust and it works great.

Probably cheaper to buy copper head gaskets.

 

[ryerye]

Really? paper is fine for the intake? Well, I'll give it a shot. In that case I guess I can reuse the original cover gaskets after soaking them - they are in one piece.
I thought I'd throw in some pictures
Here's a picture of the crack. Should I attempt to fix it? Ideas?

Still not sure about how to surface the other half

Mid surfacing the zylinder

 

[Spare_Parts]

Honestly with the gaskets soaked in oil the parts dont have to be perfectly flat. Same with copper head gaskets. They are annealed to dead soft so they will seal. Still a good idea ro flatten the surfaces that you can. The o2 sensor gasket solved my exhaust leak and has been reused several times.

I wouldn't bother trying to fix that crack unless you can weld aluminum. Still not really worth the effort.

 

[FurryOnTheInside]

I think that cracked part is usually called the "boss" and I would be enlarging that with JB Weld anyway, "case stuffing" to improve the crankcase compression.
The crankcase compression is not a lot of pressure. I've heard of 1.1 stock and 1.2 stuffed, so the case and base gaskets don't need to be anything strong or special.

(I haven't stuffed my crankcase because I was worried about getting the disassembly/reassembly wrong and knocking the crank out of true (or more out of true than it already probably is) but if you have the case apart already then you might as well.)

My cardboard base and intake gaskets swelled up when I oiled them, so I had to wipe oil on them just before they were clamped tightly between the mating surfaces.