Gasket removal help

[gleno]

It is unlikely that any mass produced engine will be able to cost effectively achieve machined mating surfaces that will not leak without a gasket. i.e. most mass produced engines.

That's one of the things a gasket is for. It remains expanded or is compressible between imperfectly mating surfaces to achieve a leak free seal.

When the sealing gasket is compressed all those little irregularities in the imperfectly mating surfaces can be cost effectively sealed with average skills and some hand tools. :clapping:

It makes sense to remove as much of the old, compressed gasket material from mating surfaces to allow the new gasket to do it's job properly.

BUT....

1) You do not have to have perfectly clean opposing surfaces, devoid of every trace of the previous gasket to allow the new one to do it's job of filling depressions and compressing between the high points. That's just anal compulsive behaviour and very few mechanics will do it. It's not functionally justified or cost effective.

2) Lankee is right. If you produce metal shavings you are gradually screwing up the surface tolerances of the mating surfaces.

3) Trying to produce a uniformly flat surface by the abrasive erosion of metal can not be manually achieved better than a CNC machined surface UNLESS you have an exactly flat surface (be it steel, stone, glass or whatever) to use a standard. This is much harder to achieve than most people think. That's why we use gaskets.

For the record I use a sharp flat blade and then stick the offending part in an ultrasonic cleaner. (that's anal) .

A dishwasher is a pretty good way to get the old gaskets off and clean your covers et at the same time (but don't tell my wife.)

 

[KJShover]

I've always used Permatex gasket remover for the stubborn ones along with my trusty, thick plastic hand held ice scraper. Never had a problem.

 

[dannymax]

I use the end of a flat mill file...used properly it works very well. You should never see metal filings during gasket removal, if you do you're not doing it correctly. Nor should you need to stone, sand or file any cleaned surface after gasket removal.

A lapping block, with the correct lapping compound, is one way to get the surface perfectly flat, or a precision surface grinder. This is not necessary as all surfaces are machined to be within acceptable tolerances (with very rare exceptions) at the Yamaha factory.

Good rule of thumb.....If the OEM gasket didn't leak a properly installed Yamaha replacement gasket won't leak either.

 

[naughtyG]

I agree. I will usually scrape the old stuff with a nice flat blade and make sure it's all feel flat (no bump etc) to the touch. The new gasket will take care of small imperfections.

Been doing this for year on all car and bike parts, and have yet to see a leak after putting it back together properly.

Depending on the gasket, proper torque of mounting bolts can also be very important. For example, over tighten a car sump or tranny cover and it will leak, because the soft gasket will have been over compressed, out of shape and destroyed.