Okay, we covered the theory and mechanics of shocks, but there's another element that needs to be critically considered anytime lower frames are discussed. Ground clearance is a crucial element. It's not all about the number or the distance from the ground to the frame. The major factor is handling and survival.
Some frames can be lowered to a delicate two inches from the pavement and still handle well because the narrow frame and all the elements attached are tucked in tight and nothing hits during cornering. Many rigids are so narrow, if the pegs and pipes are tucked in close, you're in great shape. Most swing arm frames are wider and Softail frames are the worst. They are wide and the wide component is right at the fulcrum of the frame and swing arm.
During cornering the last element a rider wants to hit the pavement is the bulkiest section of the frame. When that happens there's no flexibility left to keep the rear wheel on the ground. That's dangerous turf, so Softail are difficult to lower without damaging cornering characteristics.
In the case of Brad's '61 Panhead Progressive Suspension came up with the perfect answer, for lowering without slamming and giving proper travel with a set of their 12.5 shocks. That was very cool except for his pipes. The front header was slammed against the pavement in corners. Often pipes and pegs can be ground away without affecting cornering severely. Hell, that's why Buells and V-rods have grinding nubs on the under side of pegs, plus they're designed to fold in corners. All these elements keep the rubber on the ground through the twisties.
Brad needed to return to a nearly stock S-Pipe configuration and Paughco is the source for vintage exhaust systems for Knuckleheads, Pans, Flatheads and Shovels. We ordered all the elements necessary for the conversion and Brad went to work. In addition we took this opportunity to test the new Rivera Primo traditional English megaphone muffler.
I hope to bring you more detailed photography in the near future. Installing S-pipes is actually a very delicate operation since all the elements of this exhaust system must fit together like a precise puzzle to seal out any exhaust leaks. First the header pipes need to be fitted to the exhaust ports and made to seal. I've used exhaust gasket material wrapped around the ports or sometimes strips of beer or soda aluminum cans. The slots in the pipes need to be lengthened depending on the length of the port extension. If the pipe won't fit over the port with the gasket material it may need to be spread.
This fitting business needs to be monkey'd with until the clamps can be test-tightened and the pipes are completely sealed. But don't proceed with final clamping until all the other elements fit completely. Next, the S-pipe must be slipped under the engine to meet the front header pipe and at the same time reach and fit the rear header pipe. It's a pure slip fit, so there can't be any monkey business, bending, twisting or flexing. I've had to cut off the rear header pipe so they slipped into place. It's best to leave the header pipes lose throughout this process.
Some suggest a coating of High-Temp RTV silicone gasket maker as a final sealant between the header pipes and the S-pipe, but before that the S unit needs to reach the frame bracket, tuck up close to the frame and align with the exhaust pipe and exhaust pipe bracket without tension.
Brad made some spacers and brackets so the fit was clean as a whistle. Unfortunately, he got ahead of his super-active-self and there are still some sealing issues we need to deal with. This may seem like a pain in the ass the first time around. It does take time and patience, but once the puppy is washed and combed it's good to go forever more, as long as components aren't switched out. Once they fit and feel the road they'll come apart and slip back together like your and your girlfriend.
We'll bring you more details as we fine-tune this operation.
