Exhaust Gasket Need Changing?

[shane.ballard.nf]

I'm not sure if the gasket around the motor and header is in good shape or even present on my bike, should i replace it?
this may cause performance trouble? also should i put new springs on around the exhaust where it gets held on to the motor

this bike is old and has been abused a bit so i think it would be worthwhile to get new exhaust spring and gasket?

maybe this can help contribute to me getting the bike working good again

also the bike got a bronze dg exhaust but im pretty sure the oem gasket should work with it

 

[JST122]

shane, I cant speak from experience because I have never owned or worked on a YZ 490 but I can tell you that from working on my past and current bikes, in most cases the exhaust port gasket is a copper crusher gasket which is designed to mold to the pipe and flange of the exhaust port when it heats up. Once it heats up for the first time it takes its shape and forms a tight seal between the pipe and exhaust port. For that reason it is recommended to replace the copper crusher gasket any time you remove the pipe because once you do, you break that seal and it wont be as good as it was when first installed. The ones I have purchased in the past were about $5, but the bikes I was buying them for at the time were not as old as your 82 so parts for your bike may be more expensive due to the difficulty of getting them. Again I wouldnt know. I would replace the rubber o-rings around the circumference of the pipe, as well as the pipe springs, and the gasket all at once. It is worth replacing, especially if it hasnt ever been changed out.

 

[Big Bore Stroker]

Good reply. I add just a little bit of high temp silcone to the 0-rings on my bikes.

 

[shane.ballard.nf]

Thanks,
i guess i'll order the gasket + springs
these parts are still only cheap to get, goto wait for them to ship in tho cause i own the only 490 in my town i think

i hope the gasket is easy to install/uninstall heh

But i also want to know how much this could adversely affect performance, if a good seal is not being made?

can this make significant or noticeable power loss etc

 

[2-Strokes 4-ever]

A leak WILL effect performance........like mentioned, use high temp silicone on o-ring/end of pipe area for good seal.