Luke M. from the Facebook PC800 group recently posted some photos of his latest exhaust mods on his Honda Pacific Coast. He used a set of mufflers off a Kawasaki K1000 and welded up some exhaust pipe to make this wicked cool modification on his PC800. I’ve seen a few custom exhausts over the years but this setup really looks like it was meant to be on a PC.
This feels like the next evolution of the PC… quad exhaust just looks right. It looks retro-future, too.
Before Luke M. had the K1000 quad mufflers, he had a set of twin pipes from Blueflame on the PC. It was pretty loud. I think the K1000 quad muffler setup looks better on the bike.
A fellow PCer on the PC800 Facebook group dissected the exhaust system from a Honda Pacific Coast and was kind enough to share the photos with me. Unfortunately I don’t remember who gave me the photos. If it was you, please let me know and I will give you credit! Thanks to Jesper Milling for these photos! And thanks to Dolf for figuring out who they came from originally!
This is the muffler. One of the baffles in here causes the tweeting noise that 1989 PC800s are especially plagued with. A weld can crack and fail which makes it tweet or whistle under the right conditions.
Here’s the resonator cavity and how it attaches to the pipes coming from the engine and the muffler.
Another view of the resonator cut open.
The pipes are specific lengths to balance the engine’s twin cylinders.
A view of the dissection with the top half put back on.
One last view of the cutaway in the muffler. This is what makes our bikes wonderfully quiet.
After my little incident with a backfire causing the JB-Welded exhaust O2 sensor bung to blow out of my PC800, I decided it was time to weld up the bung properly.
As luck would have it, Andrew has a portable welder and volunteered to do some welding for me.
We had to take off the JB Weld from the exhaust to give a clean surface to weld to.
Then Andrew tacked on the O2 sensor bung with the exhaust in place.
Then we removed the exhaust from the bike. The front cylinder exhaust pipe would not detach from the resonator chamber so we ended up cutting it off with a hacksaw. Not the most ideal situation but it got the muffler assembly off.
Then we setup to weld the O2 sensor bung onto the exhaust system.
Next I put the exhaust back on the bike. I found some exhaust pipe of the right diameter to barely slip over the existing pipe. I used a couple exhaust band clamps to make the seal but the front one wouldn’t hold properly.
At least the O2 sensor is in the right place now.
At this point I also discovered that my front cylinder spark plugs were fouled. I replaced them with Iridium plugs that I had been saving for a special occasion. It was probably 40,000 miles since the last time these plugs were changed and my fuel injection experimentation certainly hasn’t helped them any.
With the exhaust still leaking from the right clamp, I had to find another solution.
Thus I made some soup for lunch with a particularly tall can.
And now I have an exhaust patch made with a soup can, exhaust putty (basically furnace cement), and exhaust tape (basically fiberglass mesh). It all holds well and I haven’t had another exhaust leak. Certainly this isn’t the preferred method of rejoining a PC800 exhaust to the bike but it’s what I had to do to make it all work. The other points where I could have disconnected the front exhaust tube were equally rusted in place as the rear disconnect point.
