QuestionIs there a gasket made for the valve cover on this motor and if so where can I get one,or do I have to rely on permatex?Have oil on top fins on left side of bike after a good run+motor cools off(not there while motor is still hot)Have already replaced all caps+O-rings above valves,can't find where the leak is coming from but suspect the valve cover from liquid gasket.
Thank You, Jeffstclc
AnswerFrom what I can find out, there isn't a gasket for the cylinder head cover and fitting one wouldn't be a good idea. This cover includes the upper halves of the camshaft bearings so if the extra thickness of a gasket was added the bearings would become lose.
It is likely that over time the cover, the head or both have become slightly warped due, perhaps, to overhating but more likely caused by someone installing the head &/or cover without using a torque wrench to apply even force on all of the bolts. Unfortunately, if this is the case, the proper solution involves machining the mating surfaces back to perfecly flat and then re-boring the bearing surfaces.
Unless you are performing a concours level restoration, it just wouldn't be worth the effort.
I would start by finding out for sure where the leak is: Clean the engine thoroughly with a proprietary engine cleaner such as Gunk or something similar and then wash it with detergent to remove any residue. When it is thoroughly dry apply a thin coating of talcum powder, flour or some similar fine powder. Go for a ride. Look at the engine (you may need to apply more powder at this point). Any oil on the surface wll show up in the powder and you should be ble to see exactly where it is coming from. It is probably there when the engine is hot but doesn't show because hot oil is so thin, but even if it really dosn't appear until the engine cools you should be able to see the pattern clearly in the powder.
Once you have found the source of the leak you may be able to deal with it.
If there is a tiny crack in the cover you could grind away some metal along the crack line, thoroughly clean the area (soak with lacquer thinner to remove any oil that has soaked into the surface of the metal) and fill it with a good quality metal filled epoxy that is safe for use at higher temperatures.
If the leak is at the mating surface, you might be able to apply a thin layer of epoxy to the area (clean thoroughly first) and sand it down to mate better. If you do this, be very careful not to remove any metal.
There is another possible solution if it is just a tiny leak and the worst thing about it is the discolouration from burned oil.
I bought my '78 GS400 with less than 11,000 Km on the odometer and quickly discovered that i had a similar problem to yours: Oil from the oil passage around the left front stud would seep from between the head and the cylinder and land on the top 2 or 3 cylinder fins where it would bake on. It wasn't leaking much - maybe a drop or 2 after an hour's run, but I was forever scrubbing burned oil from those fins.
I tore the top end apart and had the cylinders & head milled, then put it back together with a new aftermarket head gasket, using the torque wrench carefuly. It still leaked.
I replaced the head gasket with a genuine Suzuki part and it still leaked.
I finally painted the head & cylinders with black engine enamel. It still leaked, but you could only see the burned oil if you were looking for it. After that I only felt the need to clean the baked on oil off once per year, during the spring prep. I usually gave it a fresh shot of paint to touch up any paint that came of with the oil.
It still leaked when I sold it almost 20 years later with over 82,000 on the odometer.
