1979 Yamaha RD400F Daytona Special

Intended to commemorate Yamaha’s racing success, the Yamaha RD400F Daytona Special ended up as a monument to the 2-stroke motorcycles that defined an era.

White Yamaha

The forks were an inch longer than on the RD350 and were fitted with Teflon bushings to cut down friction. A large airbox dampened the 2-stroke noise.

Photo By Nick Cedar

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1979 Yamaha RD400F Daytona Special
Claimed power: 30hp @ 6,500rpm
Top speed: 98mph (period test)
Engine: 398 air-cooled 2-stroke parallel twin, 64mm x 54mm bore and stroke, 6.4:1 compression ratio
Weight (w/have tank fuel): 372lb (169kg) 
Fuel capacity/MPG: 4.6gal (40-50mpg)
Price then/now: $1,694/$3,000-$5,000

The Yamaha RD400F Daytona Special was the last hurrah of a long line of sporty midsized 2-strokes. Although Yamaha intended the Daytona to commemorate its racing successes of the previous year, this bike ended up as a monument to the 2-stoke motorcycles that defined an era. The Daytona Special was the last air-cooled street 2-stroke sold in the United States.

Once upon a time, the streets were full of inexpensive 2-stroke motorcycles. Mostly made in Japan, people either loved or hated these bikes. On the plus side, they were cheap to buy, generally easy to maintain, and typically went like stink. On the minus side, they fouled the air, made an offensive racket and often frightened people thanks to their noise and peaky power. Early ones had suspect handling and subpar brakes, but by the early Seventies the handling had improved and the brakes actually stopped the bike.

In 1973 Yamaha introduced the RD350, a 347cc 2-stroke twin that was loosely based on the then very successful Yamaha production racers. Carry-overs from the racers included the double cradle frame and much of the 2-stroke engine. Upgrades over prior Yamahas included a reed valve induction system and a front disc brake.

Yamaha engineers incorporated some interesting ideas into the powerplant, such as a small seventh port in the RD350’s induction system that fed directly from the carburetor manifold. The port provided an extra shot of fuel and air for improved combustion chamber filling and scavenging, and cooled the piston crown. As a result of the induction system — along with a well-supported, low friction crankshaft and a 6-speed transmission, the RD boasted a relatively wide powerband and a top speed just shy of 100mph. Most 2-strokes had powerbands the width of a guitar string, so the RD350 was a significant advance, making the RD a very civilized ride. The reed valve system also improved the gas mileage, another plus as 2-strokes were often very thirsty.

The RD350, although better than most of what was available, was not perfect. The front wheel had a tendency to become airborne under hard acceleration, the seat was uncomfortable after a few miles, and the oil tank leaked. But perfection was not required by the hordes of young RD fans — just speed, handling, acceleration and an affordable price, all of which the RD could deliver. Sales of RDs were brisk, and many turned up at local racetracks.

Former Cycle Guide editor Dain Gingerelli remembers that two kinds of riders bought RDs — aspiring canyon carvers and what Cycle Guide staffers called “white punks on RDs. You’d see them at the beach, dressed in a Shoei helmet, tennis shoes, jeans and T-shirts. Sort of a surfer on wheels, if that makes sense,” Gingerelli remembers.

Yamaha was aware, however, that impending emissions and noise regulations would make sales of 2-strokes more difficult. Its response was twofold. First, the company invested significant time and resources into developing a new line of 4-stroke engines. Second, it researched lessening emissions from its existing 2-stroke lineup.

Yamaha introduced the RD400, a stroked and refined evolution of the RD350, in late 1975. The RD400 featured a redesigned clutch hub and different transmission gear ratios to complement the engine’s powerband. Yamaha engineers improved the porting and added a bypass hole that ran at a 45-degree angle directly to the exhaust passage. This hole eased starting, reduced low rpm surging and quieted the exhaust note at low speed. A longer reach spark plug reduced the tendency of the RD to eat plugs. The carburetors were new, and the battery and coil ignition system was beefed up to cope with brighter lights. The frame was basically the same, but the powertrain was now mounted in vibration-stopping rubber bushings, and the wheels were seven-spoked mags, both fitted with disc brakes. The forks were an inch longer than on the RD350 and were fitted with Teflon bushings to cut down friction. A large airbox dampened the 2-stroke noise.

The engineers also added features to improve reliability and ease maintenance, including dual taillight bulbs, extra fuses, and a means to easily synch the two carbs and oil pump. Additionally, the engine was moved forward in the frame to curb the bike’s tendency to wheelie on takeoff.

Contemporary testers agreed that the RD400 was an improvement on the RD350 and fun to ride. “You can’t help but love it,” Cycle World proclaimed in a gush of enthusiasm. The road test concluded that it was the closest thing the magazine had ever seen to a perfect motorcycle. In fact, the only real complaint the testers had was that the horn wasn’t loud enough.

Other magazines pointed out that despite engine mounting improvements, too much weight aft and a little extra throttle would cause the front wheel to lift, and the front brake was strong enough it could lock the wheel during panic stops.

Cycle was known for its comparison tests during the Cook Neilson era, and the August 1976 issue featured a shoot-out between seven Japanese models conducted during a five day tour around Southern California. In addition to Cycle staffers, the riding party included Marty Dickerson, Bonneville record holder on a Vincent and still an active Vincent enthusiast today.

The Yamaha came in fourth out of seven. Despite praise for its speed, excellent handling, and low price, the bike’s lack of suitability for touring and mediocre ergonomics dropped it to mid-pack. That said, the RD400 was a clear winner in the twisties, even though much of the crew felt it was an expert’s bike that required saddle time to master. Quick steering, grabby brakes and a short wheelbase demanded rider concentration going down a twisty road at speed.

The RD400 was as popular as the RD350, and Yamaha sold a lot of them. Eddie Lawson and a host of lesser-known GP racers got their start racing RDs, as did some motorcycle journalists, including Buzz Kanter and Dain Gingerelli. Gingerelli thinks his success racing RDs was a factor in his being hired by Cycle Guide.

The next few years were spent in detail improvements, including self-canceling turn signals and a more harmonious paint scheme. Small improvements to the engine improved both top speed and fuel economy. By 1978, the Yamaha twin was the last 2-stroke road bike on the U.S. market. While all the other major manufacturers had abandoned 2-strokes for four (on the street, anyway) Yamaha soldiered on with its still popular and still fast twin, which not only sported 2-stroke power but cemented its status as a bike for real motorcyclists with kickstart-only ignition.

The Yamaha RD400F Daytona Special 

In 1979, Yamaha looked back at the past few years of its dominance in road racing and decided to commemorate its racing stars. Kenny Roberts and Mike Baldwin were then dominating Daytona and AMA racing in general. In honor of their efforts, the last iteration of the 2-stroke twin, the RD400F, was named the Daytona Special.

By 1979, U.S. emissions standards had grown increasingly more stringent, but the Daytona Special met them. The cylinder head was shrouded, there were extra linkages and hoses around the 28mm Mikuni carburetors (which were mounted on a very intricate aluminum casting), and a short cast iron exhaust manifold sprouted between the cylinder head and the exhaust headers.

All this extra equipment was intended to deal effectively with the unburned hydrocarbons that spew from standard 2-strokes at low rpm, especially during deceleration. The exhaust manifold contained vacuum-operated butterfly valves that were open during acceleration and normal running but closed and mostly blocked the exhaust when the throttle was shut, significantly reducing the flow of unburned hydrocarbons into the exhaust stream. All this made the Daytona Special run hotter, but the shrouded cylinder head effectively aided cooling, and quieted the engine, as well. Changes to the porting improved the midrange and made scavenging more efficient, and the Daytona got a mild bump in compression.

Contemporary testers praised the Daytona Special for being much easier to ride than prior RDs, with a wider powerband that started at just over 3,500rpm and pulled strongly up to 7,500rpm.

Other improvements included a larger gas tank, lower seat height and an additional half inch of suspension travel. The footpegs now bolted above the exhaust system instead of below for improved cornering clearance. All these improvements came at a price: The RD400F was no longer a bargain pocket rocket. In fact, it cost about as much as a comparable-sized 4-stroke, listing at $1,694. And that one fact might have been what killed it, as 1979 was the last year for the RD400.

The conventional wisdom holds that Environmental Protection Agency mandates killed the U.S. market for 2-strokes, but it has been suggested that the manufacturers could have made 2-strokes EPA compliant if they had really wanted to. That might be true, but it’s also been suggested that it was cheaper and easier to make EPA compliant 4-strokes instead of EPA compliant 2-strokes. Throw in the fact that riders were increasingly turning away from 2-strokes for more civilized 4-strokes and the writing was on the wall.

Two-strokes return 

Two-stoke enthusiasts jeered at Yamaha, swore at the EPA and kept riding their anti-social, noisy and fun motorcycles. At some point about 10 years ago, the remaining 2-stroke enthusiasts realized that their noisy anti-social bikes had become collectible classics.

One of these enthusiasts was Zeki Abed, whose bikes have graced these pages before, and he says this is the bike that got him into collecting. “I almost bought one when I was in college in 1980. I was poking around on eBay one evening and seeing this bike brought back that memory. It’s the most refined of all the RDs,” Zeki says.

Most RD400Fs were thoroughly thrashed by owners trying — but not succeeding — to be Kenny Roberts, but this bike was in mint condition, with only 554 miles on it. It got Zeki infected with the collecting bug, and he now has a medium-sized collection of mostly Japanese motorcycles from the Seventies.

“The Yamaha RD400F Daytona Special is much smoother than previous RD400s,” Zeki says, “and compared to the 350s, which would wheelie at the drop of a clutch, the 400 is heavier and more civilized. It will cruise at 70mph without beating you up. Even though the engine can be a little peaky, it’s more refined. There’s no premix, no problems idling in traffic, and the brakes are good. With the footpegs above the mufflers, the ground clearance was better than it used to be. With the lower seat, the bike lost its ‘sitting on top of the world’ feeling. It feels sportier than previous RDs, with an improved midrange.”

He’s kept the bike’s mileage low, amassing only a slim 400 miles since purchase, but not because he doesn’t enjoy it.

“It’s the favorite bike of all the bikes I have. It reminds me of a simpler time,” Zeki says. “Not only that, it’s fast and light. It will embarrass owners of bigger bikes. The word that comes to me to describe the Daytona is ‘nimble.’ The RD400F gets me back to the bikes of my youth. It’s the jewel of my collection.”

Dain Gingerelli shares Zeki’s enthusiasm for the Daytona. “When I was at the original Cycle Guide, we had a project in 1979 about box stock racing. We raced the RD400F, Honda 400 Hawk and Suzuki GS400. I was only able to compete in Southern Chapter races, but still finished the season fifth in points. Nothing was ever replaced on it, other than plugs, oil and those K81s,” a reference to the Dunlop tires they ran.

Unfortunately, nothing ever replaced the Yamaha RD400F Daytona Special. Yamaha tried the 2-stroke route one more time after dropping the RD in 1979, offering the sophisticated and water-cooled RZ350 for 1984 and 1985, but quickly gave up on the idea. The Daytona was the end of the line for  air-cooled 2-strokes in the U.S. MC 

roger swartout
7/10/2013 4:26:28 PM

This is an interesting story about the RD400 Daytona but it has several errors. The horsepower is 43 at 7500 rpm and it is not the end of road legal air cooled 2-storkes in the US. Kawasaki sold the air cooled, oil injected, kick start KE100 until 2001 and Yamaha sold road legal small air cooled 2-stokes in the 80s and 90s. I am a fan of the 2-stroke stories as I ride a 1976 Kawasaki KH500 and 1971 Kawasaki A7SS on the street and all of my dirt and road race bikes are 2-stroke.