Yesterday, I sealed the Tanaka three-piece expansion pipe at its three slip-fit connections. The inlet and endbleed ports were prepped, then wrapped with fiberglas sheets soaked with epoxy. The slip-fit adaptor that connects to the OEM muffler had no overlap, so I used another epoxy to try to seal the connections.
The main reason I had to seal the pipe was that leaking exhaust fumes were burning my eyes and giving me a headache. The oil spit was also getting on my clothes, frame and wheels.
The epoxy had a day to cure, so I rode a half-mile downhill to Jack in the Box for breakfast. The connections seemed intact. I used nylon tiewraps to secure the bandages. At that point, all seals seemed okay. After breakfast, I rode to Ala Moana Park eight miles away. Speeds varied from a high of 37.5 mph on the highway to 25 mph in town. The seals looked good at the park. There was a slight oil seep at the muffler flange adaptor slip-fit. When I returned home, I didn't like what I saw. The high temps at the head pipe melted the tiewrap closest to the exhaust port. The fiberglas sheets were disintegrating all the way down to the pipe. The other three tiewraps which were farther from the exhaust flange are still holding out. After I redo the seal with a different type of repair, I'll use baling wire instead of tiewraps to secure the wrap. The seal at the endbleed seems secure. There is less heat at that end, so nothing's falling apart yet.
The seal idea is good. After a wipedown, I notice that less oil was covering the frame's head tube, water bottle and the rear wheel and spokes. I originally thought the wheel was getting grime from my exhaust tail pipe. This was even though the tail pipe extends several inches past the rear axle.
Here's the pipe I'm using on my Tanaka 47R engine:
I've pulled the plug after controlled high-speed blasts over a period of several days. Plug color started at dark chocolate. Now it's at light chocolate, after the last fuel mixture adjustment.
This bike runs like a small motorcycle!