SUSPENSION & CONTROLS
Upon hearing of my project, my good friend, Kirk Cossairt, showed up at my house with a Honda CL350 rolling chassis, the Scrambler version of the CB350 As luck would have it, many parts from my CB450 frame would fit.
This frame and also the SL350 frame are AHRMA- and WERA-legal. However, the SL350 frame takes a little more work to clean up and has two front down tubes instead of one.
A word of caution:
It is important to get a clean title or Bill-of-Sale, with address, phone number and drivers' license from the seller. They do at times require the VIN (Vehicle ID Number) on tech sheets and, if your bike's VIN comes up on the stolen list, you could lose all you have worked for. Once you have a complete motorcycle, you need to disassemble it to the bare frame and swingarm. At this point you need to check for alignment to see if it has been wrecked and make sure there are no cracks.
Strip the frame with a good grade automotive paint stripper or sand blast it, since paint has a way of masking defects to the naked eye. When this step checks out you can start removing all the unwanted metal from the frame and start welding up all the pressed seams.
All areas with arrows were removed. The centerstand and related brackets, the rider footpeg mounting brackets, the bracket under the steering head, the brake pedal bracket and stoplight switch bracket as well.
All pressed seams were then welded for security and strength at speed. I chose other than stock bodywork so the mounting points for it had to be done at this time also .
The seat mount was made to fit a Yamaha TZ250 tailpiece (by National Fiberglass); the front tank mount was moved forward to fit a 1976 Honda CB400F gas tank, and a rear tank bracket was added also.
The steering stop was moved 1/8-inch higher to clear the Honda CB500F lower triple clamp and a steering dampner bracket was added. (Note: a dampner is required in WERA racing).
Unless you are an accomplished welder, make sure you take it to a professional such as Rick Breckon, owner of ROYAL WELD MANUFACTURING of Longwood, Florida, who did our work. Not only is Rick an accomplished welder but he is also the WERA National Vintage Administrative Director.
While the original suspension is adequate for a stock bike, I chose a different setup.
I used the front-end of my former Honda CB450 vintage racer because it was a bolt-on item. It consists of Honda CB500F triple clamps with tapered steering stem bearings, 1972 Suzuki GT750 fork tubes and a four leading-shoe brake laced to an 18-inch shouldered aluminum rim, 2.15-inches wide.
The rear wheel also off my CB450 vintage racer was a bolt-on item. It consists of a 1971 T500 rear brake hub laced to an 18-inch shouldered aluminum rim, 2.15 inches wide. This rim is known as a WM3 for it's width. While the shouldered rims look nice they are not really necessary. Non-shouldered rims can be used, and are much easier to clean.
Be sure to follow your rule book on rim width, as different racing clubs have different rules on this subject.
The finished rolling chassis, less bodywork, is shown in its final stage of being painted. The rearsets were pirated off a 1994 Honda CBR900RR. They are lightweight and rather short as to allow more ground clearance when cornering. These are mounted in the holes originally used to mount the stock exhaust.
The shifter had its bottom shift rod bracket cut and welded to the top of the shifter to allow more room for the exhaust to tuck under the frame and foot peg. The front shift shaft lever also faced upwards and was off the CBR900RR as it was longer and allows for extremely smooth shifts. With the rear T500 brake being cable operated, be sure to mount a brake lever stopper, so it won't return all the way up or flop around on you.
The rear shocks are 1/2-inch taller than stock and are dampening adjustable. While assembling your rolling chassis, I recommend replacing all bearings, i.e.: steering stem with tapered roller bearings, wheel bearings with double dust seal type, new swingarm bearings and bushings (bronze bushings if you can find them or have them made). Any play in these areas and you may get into a tank slapper you may not get out of!
In the control department I used a set of clip-ons rather than clubman bars, which work just as well, because of their adjustability up and down the forks. For the clutch side I used a Suzuki GSXR clutch lever and perch with the ratchet adjuster for clutch cable slack. The reason behind this is if the starts are held up and your clutch gets hot, you can move the adjuster with one hand rather than having to loosen a nut first, keeping your bike from creeping, which will definitely get you black flagged in WERA events.
For the brake side I used a 1972 Suzuki GT750 brake lever and perch that accepts two brake cables for the Suzuki 4LS front brake. The throttle was off the 1976 Honda GT500 with an on-off switch wired to the Motoplat Ignition from Todd Henning, which we will cover later.