gasket failure

[james butler]

why do gaskets fail over time?
especially crank case gaskets typically to prevent oil leaks?
i have an old motorbike i never use but ive noticed its started leaking, i haven't ridden it in years so why has it started leaking now?
it seems things leak from a lack of use, rubber seals i can understand as they dry out or perish over time but why do paper gaskets or that gasket sealant leak after a period of time/lack of use?
is there a way to prevent it? ie drain the oil out?

 

[rcx132]

Can't imagine why they leak but I have a solution that someone mentioned and worked for me.

Superglue. My KTM was leaking from it's main crankcase split joint, the one that runs down the middle. Can't remember if it was a paper gasket or silicone. Low mileage bike and was loathed to strip an engine to fix that. I was told to use the runny grade hobby store glue, apply from the outside. It stopped the leak, had that engine for 5 years or longer, it never leaked again.

 

[Kayos]

Superglue?

I'm going to need a big bottle for my Disco

 

[The_Yellow_Ardvark]

@Kayos
This will do as a small start.

 

[awemawson]

Changes in temperature and differential expansion and contraction of different metals. It puts a shear force on the gasket such that sometimes the two faces move ever so slightly relative to each other.

 

[angellonewolf]

lsx leak sealer could work ? dont know if it will cope with oil but works wounders on rads

 

[james butler]

Changes in temperature and differential expansion and contraction of different metals. It puts a shear force on the gasket such that sometimes the two faces move ever so slightly relative to each other.

i could understand that if i used it but i don't use it. its started leaking all on its own

 

[addjunkie]

Use a traditional british bike fix

https://www.matalan.co.uk/product/d...MIh46rlZCX2gIVSrHtCh1aIwypEAQYCSABEgJ_8PD_BwE

 

[Ashley Burton]

Heat cycles make the gasket change characteristics as time goes on, Some gaskets go rock solid, Others just break up. I do love an oil or coolant leak!

 

[awemawson]

i could understand that if i used it but i don't use it. its started leaking all on its own

And you keep it in a constant temperature environment - I don't think so

 

[zx9]

lsx leak sealer could work ? dont know if it will cope with oil but works wounders on rads

LSX is cured by exposure to moisture so I doubt it would work with oil.

 

[angellonewolf]

^^^ go to know thanks

 

[dannyp]

it wanted an oil change

 

[zeppelin builder]

why do gaskets fail over time?
especially crank case gaskets typically to prevent oil leaks?
i have an old motorbike i never use but ive noticed its started leaking, i haven't ridden it in years so why has it started leaking now?
it seems things leak from a lack of use, rubber seals i can understand as they dry out or perish over time but why do paper gaskets or that gasket sealant leak after a period of time/lack of use?
is there a way to prevent it? ie drain the oil out?

Alot of old bikes have gear oil pumps and the oil in the tank will eventualy seep past the gears and fill the crank case full of oil then it gets into clutch case and leaks out of very basic seals
Thats why a lot of oldies have the suicide tap on the feed pipe
Best drain the sump and refill the tank when you start it or you be in a smoke screen

 

[merryman]

I have a solution that someone mentioned and worked for me.

Superglue.

May stop leaks, but how do you split the cases again? I find many are difficult to split with just paper or goo between them. I can imagine superglued surfaces being impossible.

I can understand paper gaskets leaking over time, as paper isn't oil-proof, when compressed it may be, but if the mating surfaces were perfect there would be no need for a gasket.