Yamaha Seca II - Clutch Cover Oil Leak

Spontaneously during a long trip this summer my 1993 Yamaha Seca II developed an oil leak. From what I could tell, the leak was coming from the right side of the motor concentrating itself on the oil pan. From what I could tell, the oil leak would only appear when the motor was running and under pressure.

Along with the oil pan, oil spray had covered the bottom of the swing arm, and exhaust. Curiously the leak would stop when the engine cooled down.

Justifying to myself that it was time for an oil change anyway, I went ahead and pulled the oil pan.

It didn't take long to remove the exhaust and the oil pan bolts however, once I had gotten the pan free I noticed that the paper gasket had delightfully mated itself to both the pan and motor. After more than an hour of scrapping and an entire box of razor blades, I had the pan and the motor prepped for the new gasket. The installation was event free although I did notice that I could not find a tightening pattern for the oil pan bolts in the shop manual.

A quick ride around the block revealed that I did not solve the oil leak. I started questioning everything. Was the pan warped? The crankcase breather clogged? Oil cap loose? I began combing over the bike. I removed the gas tank and checked the breathers and upper portion of the motor. From what I could tell, the leak was low. None of these questions would be answered until I began a new project, the exhaust.

As part of my maintenance when changing the oil and pan gasket I decided I would repack the Yoshimura 4-1 exhaust. Trying to repack the exhaust was nightmare. After several attempts to remove the muffler I enlisted some extra man power and an assortment of destruction ensuing tools such as, a large vise, chisels, rubber mallets, and a blow torch. When I was left with a charred contorted Yoshimura I came to the comforting conclusion that this pipe was better suited for the trash.

The day I dumped that pipe I ordered a set of Delkevic 450mm Oval Silencers (review to come). During the installation the new exhaust I noticed a mark on the side clutch cover. After the installation I fired the bike up and looked over the exhaust. It was then that I spotted the leak. The leak had been coming from a small section of the clutch cover, running down the lower side of the motor and spreading across the oil pan gasket. I quickly ordered a gasket from my local Yamaha.

When I received the new gasket I began the unbolting process. With two bolts successfully removed the third bold sheared completely off. Wonderful. The other bolts came out without an issue. As I searched around the garage for my extractors, I reached for a small pair of vise grips. The last thing I wanted to do was to mash what was left of the bolt ruining any purchase I would have with the extractors. But I took a chance. The vise grips grabbed the bolt nicely and I was able to back the broken bolt out. I now settled in with a fresh box of razor blades and began scrapping.

Once I had the surfaces clean I reinstalled the clutch cover with a new gasket and a replacement bolt for the deserter. During the reassembly, I tried to remember the general position of the clutch cable and hoped for the best.

The Yamaha fired up with no problem. I let it run for a good while. No leak. Perfect! My next thought was to test the clutch. As soon as I pulled the clutch in and put the bike in gear the motor died. Crap. Maybe I didn't get the clutch cable set right?

After that I called it quits. Also I promised to take my wife out to dinner.

While in the shower, of course, I nearly laughed myself stupid. A Yamaha Seca has a kickstand safety switch. A short time later I fired up the Yamaha, properly put the bike in gear, looked at my unenthusiastic wife, and let the clutch out with a satisfying feel.

Since that time I've put several leak free rides in on the Yamaha. I can now move on to the next project, adding side case mounting brackets.