Valve cover gasket replaced. Now leaking by valve cover side cap. What to do?

[Guest]

Hi

i have a 1979 suzuki gs750l. I recently had a mechanic run a leak-down test, adjust the valve cover clearances and get them set right, and replace the valve cover gasket (it was probably an aftermarket gasket as it only costed $12.95). The leak-down test revealed that i have one cylinder with lower compression (70psi) than the others. I believe he tried to soak the cylinder to see if i had a ring that might have been stuck. He also must have ran the engine hard as he indicated that he attempted to remove any carbon buildup in the cylinders. The engine started a little hard and ran a little rough on the way home when i picked it up. However, i did not think much of it at the time and did not notice any oil leaking from the valve covers as evidenced by smoke coming off the hot engine after riding it home. After a couple of days, i replaced the spark plugs as they looked pretty blackened after the "repairs" upon inspection. I also removed the old oil and filter as the oil looked darker (it was quite dirty) than it had been and the filter ended up being in pretty bad shape when looked at. New oil was put in and a new filter was installed as well by me. For the oil, i put in a synthetic blend of oil of 5w-20. After running the motorcycle for a while i observed some smoke coming from the front right side of the engine. I then saw some oil dripping down onto the engine from the valve cover. After talking to a friend, i realized that i should not have gone with the 5w-20. Per specs, i should have gone with 10w-30. Whether the synthetic blend contributed to the problem i do not know. I then removed the 5w-20 synthetic blend. I then cleaned around the valve cover with an engine degreaser and washed and scrubbed the area with water and let it dry. I then filled the engine with valvoline 10w-30 premium conventional oil. After running the motorcycle for a while, i observed oil leaking near one of the valve cover side caps. Could there be an easy fix to all of this?? Or should i just call the mechanic and drive the motorcycle 20 miles to get to his shop and let him deal with it??

Any help would be appreciated.

Bigcheese

[tkent02]

Use 10-40, no thinner. Thicker oil is OK but it's not needed. A lot of us use Rotella 15-40, it's as good as any. Synthetic or not doesn't matter for the clutch. The clutch will probably slip with that 5W-20 or even 5W-30 oil, as it's probably "energy conserving" car oil which means it's no good for the clutch.

After changing the valve clearances the carburetors need to be synchronized, not doing this is probably why it's now running rougher. Have you done anything to the ignition? Contact points style ignitions do need a little maintenance once in a while. Easy stuff but it does take a few minutes, more the first time. Something not right in there will also make it run rough. Or not at all.

The valve cover gasket is easy to fix, the rubber half moon cam end plugs are easy to replace, or you can seal the old ones with Threebond or similar. He may have tightened the valve cover bolts too tight, which will make it leak. Or didn't clean off the gasket surfaces. Or used a crappy gasket.

Ride it a bunch and then check the compression. It will probably come up. Most likely he set a valve or two too tight and this killed the compression in that cylinder. Learn to do this stuff yourself, it's easy.

No one will pay as much attention to your bike as you will. You want it done right do it yourself.