Got the dual exhaust put together and mounted. Fitting and welding went super smooth and turned out awesomer than awesome thanks to Dave from the H8Rcc (of which I am now officially a member). We ran the pipes all the way back, over the axle, between the leaf and frame, and turned them down inside the rear of the rear fenders. Totally stealth. Initially at idle it was loud but still sounded pretty good and engine braking gave me a fantastic Harley-esque burble and pop. Unfortunately, just cruising around it was WAY too loud and pretty much droned like I had a busted muffler the entire time. I partially attribute this to the fact that I have a 3OTT and 4.11 so it doesn’t wind up or down very quickly and partly to the fact that the 2.25″ I.D. pipe is totally overkill for a 216. Drove it around a couple nights and I couldn’t stand it. Acceleration sucked too. Kept stumbling and stalling…turns out I had a massive vacuum leak at the base of the carburetor as well.
So… How to fix the sound? Motorcycle baffles.
Seeing as I already had a big ass pair of 30″ fiberglass stuffed Smithy’s under the cab, I knew I didn’t want to add just another set of glass packs or resonators. I wanted tough, crisp and raspy with out being high pitched and my experience with a warmed over ’74 750 Honda with an open 4-1 megaphone got me thinking about tuning pipes and restriction/choke plates which in turn lead me to Khrome Werks, which is where I discovered their 2.25″ O.D. HP-Plus baffles for Harley drag pipes. After a quick conversation with their tech dept (they design/build everything they sell) I figured, based on the construction (see pics below), they’d be the best solution.
They were. First off, the tech gal was caught totally off guard when I told her what I was doing but she hung in there and offered educated discussion based on my description of the situation and assessment of the issue. Second, the baffles don’t look all that impressive (actually they look a bit gimmicky to be honest) but they are made to take the edge off a loud pipe and they do just that very well. I broke the pipe at the slip fits behind the Smithy’s and slid the baffles in. They were such a perfect fit that I simply flared the edge of the insert with a pair of channellocks and tapped them into place. The 2.25″ baffles are actually Khrome Werks’ 2″ baffles enclosed in a tube which is bumped out to 2.25 O.D. at the ends, I think this 1/4″ choke helps a bit too. Once I had her fired up I could immediately tell that the baffles took everything way down sound-wise but left just enough of the 6cyl crackle. Should get better as the as the glass packs burn out too. In my opinion, it sounds better (less raspy and much less high pitched) than my buddy’s Fleetline with a 235 and long 1.75″ straight pipes.
Time to move on to the vac leak which I solved by cleaning up the intake/carb surface and using a thicker gasket. Now sealed and retuned, she sings perfect idling at 650-750rpm and cleanly revs up to 1500 with no stumble.
…this is when I noticed oil pissing out the copper line that weaves through the block and feeds the rocker shaft. FML.
Khrome Werks 2.25″ HP Plus baffle.