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Clutch Cover Pitting/Corrosion


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Hi all

Next problem ....

Clutch cover recently wore through at the very bottom (see first pic)

Replaced with new one and rode it once and the water pump seal failed and dumped water into gear box.

Pulled brand new cover off and found this significant pitting/corrosion at the very bottom (see 2nd pic)

What's going on ???

There are no metal bits floating around in there. Magnetic plugs clean.

Could the oil/water mix be corrosive enough to cause this ???

And, why on God's earth does GG paint the inside of these covers ???

The paint just peels off with obvious undesireable results !!!


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Frustrating for you to say the least..i bought a brand new 2006 beta rev 3 ..the clutch case corroded away within a year despite using the most expensive coolants..complained direct to beta italy..they produced an upgraded case that didnt turn to snot therefore admitting the original part was not fit for purpose..i still had to buy the part..frustrating..magnesium alloys are a mix and can be made at manufacture good quality or poor...look at honda cases they stay immaculate ie good quality mix of mag alloy...you havent done anything wrong ..the manufacturers should get a grip and produce bikes fit for purpose..frustrating..hard earned cash an all that....frustrating

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As for a cure... the case wont pit all over just in areas of impurities in the mix..hopefully...sand it back and seal the pits with e metal..dont use much just fill the pits..then spray paint the infection with a quality paint..hope it stops the corrosion progressing

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You say "water" but do you mean coolant?

This type of corrosion is caused from the coolant sitting in the bottom of the clutch case. When your water pump seal fails it leaks into the side case.  As oil floats on water (or coolant in this case , usually some form of ethylene glycol and water) the coolant ends up pooled under the transmission oil in that area. (it's the lowest point).

That is partially why there is a glass oil sight, so you can check oil level, but also oil condition.

If it goes the slightest bit milky that is usually a sign of contamination.

Some coolants will do this when left in the side case, and also play havoc with the friction material on the clutch plates.

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