Why the Honda CB350 is the go-to motorcycle for vintage racing
Jim Korn sat astride his 1972 black and silver Honda CB350, tensed for the start of the Novice Historic Production Lightweight class race at Gingerman Raceway in South Haven, Mich. The class is open to a who’s who of notable 1972-and-older machines—BMWs, Moto Guzzi 500s, Ducati 450s, Kawasaki A1s, and Triumph 500s, among others.
But when Korn took inventory of the dozen bikes competing in his class, he saw a familiar model. “There were eight 350s,” said Korn, who also races his CB350 in the Heavyweight class, where he is the current points leader.
The concentration of CB350s is no fluke. At American Historic Racing Motorcycle Association (AHRMA) road races, CB350s are likely to pack the field—from bone-stock bikes in the Production Class to machines with barely an original engine part in the Sportsman Class.
The CB350, produced from 1968–73, has proven reliable, easy to work on, and comparatively inexpensive to buy. Plus, parts are still readily available. It’s no wonder then that the CB350, successor to the CB77 Super Hawk, was also popular back in the day. It improved on the Super Hawk’s stressed-member design, which used the engine as a part of the frame, by employing a stiffer “cradling frame” and larger drum brake up front. A shorter wheelbase improved handling.
Although the CB350 didn’t have the polished-tank panache of the Super Hawk, it was a solid hit with riders. According to Honda, during its six-year run, the CB350—including the Scrambler-style CL350—sold 319,712 units in the U.S. It is among the all-time top-selling Honda street bikes in America.
The CB350 wasn’t particularly racy in performance or looks—a problem worsened by what may now be recognized as regrettable paint schemes like Iris Purple, Candy Gold, and Candy Bacchus Olive. But the CB350 excelled in durability. “If you didn’t run them out of oil, and adjusted the valves occasionally, they just kept running,” said Jon Seidel, a spokesman for Honda Powersports.
That combination of popularity and durability meant that when the model had reached vintage racing age—bikes built in 1972 and prior qualify as vintage for AHRMA road races—there were plenty of CB350s around. By the law of supply and demand, the large supply kept the prices low. “Twenty-five, twenty-six years ago these old bikes were everywhere,” said Charlie O’Hanlon, who owns Charlie’s Place, a Glendale, Calif., shop specializing in vintage Hondas.
O’Hanlon initially thought the CB350s were junk because the ones he saw were always in poor condition, but found “it was really the opposite.” Without even basic maintenance, O’Hanlon realized, “these bikes that had been around since the ’70s were still running. Looking back on it now, it’s amazing. We’d ride them until the chain was so loose it came off.”
In addition, CB350s are simple enough for a shade-tree mechanic to tackle. “You don’t need to be a tuner to get them race ready,” O’Hanlon said.
That has helped make the CB350 a go-to bike for entry level racers. “You can go racing for two to three grand,” said Cynthia Cowell, AHRMA National Roadrace Director. “You can try it out, and if you don’t like it, you can sell the bike for what you put in it, basically.”
That may be the case for Production Class, which requires that the bikes that are nearly stock, differing mostly in that lights are removed and clubman handlebars are allowed. Scot Fiedler, winner of the 2016 Novice Historic Production Lightweight class, runs a CB350 which uses a t-shirt from his sponsor—Dime City Cycles, a restoration parts specialist in Largo, Fla.—as a seat cover. “Mine is the epitome of the production bike,” Fiedler said. “The motor got freshened up, but nothing else went into it.” He estimates he spent $1,200–$1,500 to prep the bike for racing.
The economics are different when modifications are permitted, however. In the Sportsman Class, for instance, there are few limits on improvements, and the faster riders want to go, the more they have to pay.
For racers like Scott Turner, the 2016 champion in the Sportsman 350 Class, the CB350’s durability makes it extremely attractive. “Why do you think we can take that motor, get 50 horsepower out of it, and have it last six seasons at the track?”
Turner’s modified CB350 gets roughly twice the output of the stock Honda motor. He bored the engine 2mm larger, traded out the stock 7mm valves for a 5mm Kibblewhite valve train kit, and ported the engine. He traded the stock Keihin carburetors for Mikunis, and the crank was lightened, trued, and welded by Falicon. The changes allow for higher output and higher revs, taking the engine from the stock 9500rpm redline to 12,500, said Turner.
Turner, who like Fielder is sponsored by Dime City, also modified the frame using parts of a Honda 360 for added stiffness, an improved swing arm, and a lower height to fit him better. A front drum brake from a Yamaha TD2 upgrades stopping power from the stock setup, but it still fits the vintage requirement.
A closer-ratio fifth gear, for more consistent shifting, rounds out the modifications. “You kinda gear to the track, but I gear to where my shift points are. You don’t want to be shifting in the middle of a turn.” Turner also swapped out the front sprocket to preserve top speed. He said a GPS-equipped rider at Daytona clocked him at 129 mph.
In the end, virtually no part went unmodified. “We are touching everything,” Turner said. “To have a Sportmans motor you have to spend at least six grand. You could do it for as low as $4,000 or $5,000, but it won’t last. Some people spend $10,000.”
The increasing costs are a lamentable reality. “It used to be that you could run Sportsman with a solo seat and rearsets,” Turner said. “As competitors we ruin every class we get into. I’m guilty, too.”
In fact, the CB350 is becoming a victim of its own success. Demand continues to rise, and prices have risen in lockstep. Rusty CB350 project bikes bring $600–$800 on eBay, and running bikes, even in rough shape, bring more than $1,000.
The rising costs have even hit the economical Production Class, as it requires original equipment Keihin carbonators. A Keihin carburetor body on eBay runs $100–$300, and O’Hanlon said a rebuild at his shop costs about $300. It’s one job that is tough for amateurs to manage. “You can read how to clean them out,” O’Hanlon said, “but we are seeing problems that developed because of age, so you won’t find that in a Haynes or Clymer manual.”
As Turner said, “When you find a good carburetor, you’ve found gold.” That seems to ring true of most CB350 motorcycles, even those in unsightly Candy Gold paint.