Engine Just Blew??

I can't believe it, but my valve cover gasket blew again!! It lasted quite a while this time but that's 2 in only 180 miles. I thought the sanding and hi-tac would do the trick, but I think those super thin blue gaskets are just too thin. They are only half as thick as my old gasket and probably 1/4 the thickness of the old stock rubber gasket.

Does anyone know of a source for a good quality valve cover gasket? The factory Kaw part lists at $66 but I'd pay it if I knew it was the old thick rubber type. I can't seem to find a good one around anymore. The Vesrah brand gaskets are quite a bit thicker but not nearly as thick as the original.

Scrap that chrome cover. I had one and had the same problem, even after I roughed it up. Also, use the thick, fiber gaskets and it should eliminate your problem. If it still persists, take a sharp center punch and put a small dimple about every inch all the way around the mating surface of the cover. This raises a little circle of aluminum a few thou high that grips the gasket. If all this fails, try venting the cover itself with a brass bung and a long hose.

thats a beautiful bike man, i had an 80 MKII, i should have never sold it, tried to track it down to maybe buy it back, but no luck.

make sure the cam tower isnt holding the cover up

79MKII wrote:

...valve cover gasket blew...that's 2 in only 180 miles. I thought the sanding and hi-tac would do the trick, but I think those super thin blue gaskets are just too thin. They are only half as thick as my old gasket and probably 1/4 the thickness of the old stock rubber gasket.

Does anyone know of a source for a good quality valve cover gasket? The factory Kaw part lists at $66 but I'd pay it if I knew it was the old thick rubber type. I can't seem to find a good one around anymore. The Vesrah brand gaskets are quite a bit thicker but not nearly as thick as the original.

On my Z1, am well satisfied with the valve cover gasket from Z1E.

Valve cover gasket

It's relatively inexpensive, and seems pretty thick, but it is blue, and I don't know the brand.

In any event, it installed easily (completely dry install), laid nice and flat, and hasn't leaked at all after a thousand or so hard hot miles.

Remains dry and blue around the edges.

Good Luck!

[Click on image to enlarge view]

79MKII wrote:

I can't believe it, but my valve cover gasket blew again!! It lasted quite a while this time but that's 2 in only 180 miles. I thought the sanding and hi-tac would do the trick, but I think those super thin blue gaskets are just too thin. They are only half as thick as my old gasket and probably 1/4 the thickness of the old stock rubber gasket.

Does anyone know of a source for a good quality valve cover gasket?

Auto Zone. I used their gasket material that is 1/32" thick, I believe it is labeled vulcanized fiber material or something like that (it's rubberized paper). I think it has a number like N8904 or similar on the back. I used it for both the cylinder base gasket and valve cover gasket and it has held up very well for two years after the Athena gaskets failed almost immediately after installation.

I have also found a thin bead from a tube of the black ultra high temp gasket maker will hold the gasket very well. Stays pliable, easy to remove.

bountyhunter wrote:

...Auto Zone. I used their gasket material that is 1/32" thick, I believe it is labeled vulcanized fiber material or something like that (it's rubberized paper). I think it has a number like N8904 or similar on the back. I used it for both the cylinder base gasket and valve cover gasket and it has held up very well for two years after the Athena gaskets failed almost immediately after installation.

I have also found a thin bead from a tube of the black ultra high temp gasket maker will hold the gasket very well. Stays pliable, easy to remove.

Did you cut your own gaskets?

u should consider increasing the crankcase vent area, if u havent already. with bigger pistons u have more crankcase preasure. this is a common problem for leaks on the old Z's.

mark1122 wrote:

u should consider increasing the crankcase vent area, if u havent already. with bigger pistons u have more crankcase preasure. this is a common problem for leaks on the old Z's.

I think you're right. I'm hoping the pressure drops as the engine breaks in and has less blow by?? I still only have 180 miles on the 1261cc rebuild. I have since added a vent to the oil fill cap and thought it was the trick - guess not!

Is there a common mod for the stock crankcase breather to open it up?

TerryK wrote:

Scrap that chrome cover. I had one and had the same problem, even after I roughed it up. Also, use the thick, fiber gaskets and it should eliminate your problem. If it still persists, take a sharp center punch and put a small dimple about every inch all the way around the mating surface of the cover. This raises a little circle of aluminum a few thou high that grips the gasket. If all this fails, try venting the cover itself with a brass bung and a long hose.

TerryK wrote:

TerryK wrote:

Scrap that chrome cover. I had one and had the same problem, even after I roughed it up. Also, use the thick, fiber gaskets and it should eliminate your problem. If it still persists, take a sharp center punch and put a small dimple about every inch all the way around the mating surface of the cover. This raises a little circle of aluminum a few thou high that grips the gasket. If all this fails, try venting the cover itself with a brass bung and a long hose.

Prior to this most recent rebuild, my chrome cover made it 20 years without a drop of oil leaking - that was with a much thicker gasket though. I currently have vents at the crankcase breather and the oil fill. I might have to add another on the valve cover as you suggest.

Have you replaced the cam cap bolts? Allen head bolts sit too high and the valve cover can hit on the tops of them. If this happens, the gasket isn't being compressed properly.