About racing the 350 Honda:
Strip off the street gear. Pull the electric starter & chain and plug the starter hole. Race with the stock seat and tank if you wish. I’ve found the SL350 tank (with no crossover tube) and a fiberglass café racer seat works for me. Clubman bars work to get you started, and you may want to wait until you’ve upgraded your front forks to 35mm to buy clip-on handlebars. Pull the wiring harness and install a simple wire to a switch that feeds the coils power from the battery mounted on your handlebars or tach gauge mount marked run & off. A steering damper that mounts between the frame and the forks or triple tree is required as a safety feature. The early model CB350s came stock with a steering stem mounted damper that will qualify. 520 chain and sprocket conversion is something to consider when you wish to lighten the load while maintaining the same tinsel strength. The stock steel wheels are heavy and can be replaced with aluminum rims.
This will give you a gist of what can and should be considered.
I and a small handful of guys race 1968 – 1973 CB350/CL350/SL350 Hondas with WERA. We are a jovial group that does whatever we can to help each other get on the track and into the grid. Then, when the green flag waves, we go out and have a blast riding on the same race tracks that the “modern bike guys” race on. We actually take turns with them. They get a race session, then vintage guys. There are a bunch of classes out there, but the 350 Honda racing has the benefit of the guys that are just great to be around.
The least expensive means of racing, and the class I race in and known as “CheapJack” is the “stocker” class. It’s limited as to what you are allowed to do to modify the bike, which restricts the expenses and speed of the machines. You must run stock Kei-Hin CV carburetors and are only allowed to bore the cylinder to 1.0 mm over stock specs. Only drum brakes available when the bike was on the showroom floor. No material added or removed from the engine. This restriction guarantees that the 335cc engine (once over-bored by 1.0 mm) will never break 100 mph on the GP tracks we run.
The significantly more expensive class is allowed to punch out the 325cc engine to 362cc with custom high lift and variable timing cams, porting heads, blue print balancing the crankshaft, dual plug heads, larger valves and seats, Mikuni carburetors, transmission mods, etc… are allowed and represent the more expensive investments and higher performance results.
About vintage motorcycle racing:
One thing to keep in mind is that no matter just how intense your delusions of grandeur may be, your first time at the track, it’s all a matter of a learning curve. Also keep in mind, and become a part of, the philosophy of a vintage motorcycle racer. There are NO A.M.A. scouts looking to see if you have the skills to be drafted as a manufacturer’s sponsored racer. You’re racing with a bunch of guys who are looking ahead to the last race of the day, which will see them to the last race of the season, and looking for the last race before they’re too old to race, usually in your 70s, I’m shooting for my 80s before giving up.
Types of vintage motorcycles to race:
There are 2 stroke classes and larger 4 stroke classes than the GP350. However, one thing about performing well in vintage motorcycle racing is to run a reliable machine that finishes as many races as possible. That’s where the “bullet-proof” 350 Honda twins come into play, before you beef them up to almost double their horsepower in the V1 class. The natural progression for those who have completely refined their GP350 race bike is to make the last jump and make a V1 powerhouse motor. Until then, there are many refinement allow for the 350 Honda as you get closer to having a V1 bike with a GP350 motor.
Any ignition system is allowed in the WERA GP350 class. Starting with the stock points system will get you on the track. My bike came with a modified Dyna-S electronic ignition without timing advance. This means the engine is running at max timing advance no matter what engine speed its revving or idling at. Any electronic ignition system requires a battery to operate with. The 12 amp, stock type, lead-acid battery, when new, can be charged the night before and take you through two practice sessions and two races in one day without a recharge on either the points or electronic ignitions. There are six and eight cell lithium batteries (much less weight and noticeably higher cost) that will perform for the same interval with the same ignition systems. The most expensive ignition system, a PVL, does not require a battery, so you can calculate that into your cost benefit analysis. It’s a magneto system that is set up once on the crankshaft and can stay forever, if you don’t have to pull the crankshaft through the engine case as might be the case in an engine rebuild. The self-generating spark generator is the racer’s choice for all concerns, barring expense. At around $500, it’s a big investment.
Any internal expanding drum brake system may be used with the 350 Honda in the GP350 class. Mr. Michael Mercury Morris of Vintage Brake give the stock front brake system an honorable mention as a suitable brake for vintage racing. Adding new, modern brake shoe material and fitting it for the drum to get maximum mating surface area will yield a mighty fine brake setup for the 350 Honda with a GP350 powered stocker motor. V1 powered 350 Hondas can slingshot into much higher speeds and are better suited with either a bigger and better drum, or perhaps a disc brake system. Other easily configurable front brake options for the GP version include the CB77 (305 Super Hawk) or the CB450/CL450 front drum brake. As the CL450 front wheel was a 19″ version, re-lacing the hub to an 18″ is recommended, but not required by rules or tire selection. Most vintage motorcycle race tire manufactures offer a 19″ tire suitable for the CB350/CL350.
WERA offers different bikes to “bump up” to the next fastest class. Most of the bikes in the GP500 class are 350 Hondas that also run in the GP500. So, we get two chances to play with our buddies using the same race bike. On occasions, actual GP500 race bikes show up and remind us that we are just running around the track with 335cc of two valve per cylinder, 26 horsepower while that may sometimes lap up in just 8 laps.
With the advent of GoPro cameras and their competitors, we get to record the events, which include crashes, for all time. There are plenty of close calls which make the time on the track exciting. The time in the pits with other racers is a hoot. You’ll get lots of tips and pointers worth listening to.
As for race schools, I’d recommend taking the $75 (last I checked) WERA race school and sign up for at least one race near the end of the day’s schedule. Your first two races (at least, longer if you’re not comfortable is your option) you’ll be wearing a fluorescent t-shirt from the race school as an indicator to other racers of your lack of experience. After successfully completing two races without crashing, your provisional novice status is upgraded to novice. Then, spend most of the rest of the season learning what was discussed in your down and dirty inexpensive race school. As you approach the end of your season’s experience, consider taking a serious race school, like the Ed Bargy Race School, now that you understand what racing is all about you won’t get lost in all the new terms and theory only understanding. You’ll get a lot more out of it than you would have as a newbie.
One way to look at your early races is to view it as very cost-effective track rental. As a newbie, you’ll be put at the back of the pack in your class for grid placement. When the flag goes green, the faster racers will take off through the turns that they have learned over the years. This leaves you with everybody in front of you, at least for 5, 6, maybe 7 laps, with the track all to yourself. You get to experiment with your approaches, the speed of your engine, the handling of your brakes and suspension system, while building your confidence.
As the fastest and most experienced of the racers come up from behind you, you’d be best served to remember everything you learned in class and play it by the book. One of the many things you’ll learn is how to get passed by a faster racer without getting flustered. Then, you’ll learn to draft them to pick up your speed. As you’re passed before curves, you’ll get to trail the faster racer and follow the lines he takes. The next time round the track, taking that path, will give you more insight as to how best to approach and depart the curve.
Until your second time at the same track, you’ll be learning all new curves as well as the handling of your machine. As your times get faster, you can work practice sessions with other racers who will “hang back” for a lap or two in order for you to put a few curves together. The exit for one curve should set you up for the best trajectory to enter the next curve. Lap after lap the track becomes a contiguous line connecting the curves together and the thrills accelerate. Remember, “life begins at 45 degrees and goes up at a parabolic rate”.
Having enjoyed bull riding (age 19), skydiving, motorcycle touring, submarine riding and a few other risk taking adventures, I’ve found my excitement with vintage motorcycle racing on a bike that never breaks 100 mph. With the modest powered 350 Honda, you can’t buy your speed back with the throttle if you scrubbed it off during the curves. So, lean deep into the curves, draft behind the guy in front of you until you get the chance to pass him. Until then, follow close and learn the track you’re on. There’s always more to learn and rubber to burn.