Lot 364 - 1979 Yamaha RD400 Daytona
|Odometer reading||40,000 km|
|Estimate||£5,750 - £7,250|
The RD400 was the last of the famous line of twin cylinder two-stroke sports motorcycles produced by Yamaha starting with the introduction of the RD350 in 1973, which was loosely based on their very successful production racing machines. Features carried over from the racers included the double cradle frame and much of the two-stroke engine. Upgrades over prior Yamahas included a reed valve induction system and a front disc brake.
Yamaha's engineers incorporated some interesting ideas into the power plant, 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, cooling the piston crown. As a result of the induction system - along with a well-supported, low friction crankshaft and a six-speed transmission, the RD boasted a relatively wide powerband and a top speed just shy of 100mph. Most sporting two-strokes had very narrow powerbands, so the RD350 was a significant advance, making it a very civilized ride. The reed valve system also improved the fuel consumption, another plus as two-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.
The RD400, featuring a longer stroke, was introduced in 1975. There were many other improvements including revised porting, different gear ratios and rubber mountings for the engine and disc brakes now on both wheels. Additionally, the engine was moved forward in the frame to curb the bike's tendency to lift the front wheel under acceleration
The RD400 proved popular and sold well. It continued in production over the next few years with many detail improvements ,when in 1979, Yamaha decided to celebrate its dominance of road racing over recent years and commemorate its racing stars, Kenny Roberts and Mike Baldwin, who were then dominating Daytona and AMA racing in general. In their honour 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 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, in fact, the engine ran quieter. Other improvements included a larger fuel tank, lower seat height and an additional half inch of suspension travel. The foot-pegs now bolted above the exhaust system, instead of below, for improved cornering clearance. The claimed power output of 30bhp was sufficient to propel the RD400F to a top speed of 98 mph achieving a standing quarter mile in 14.15 seconds.
The conventional wisdom holds that Environmental Protection Agency mandates killed the US market for two-strokes, but it has been suggested that the manufacturers could have made two-strokes EPA compliant if they had really wanted to. While that might be true, it is probably fair to say that it was cheaper and easier to make four-strokes compliant with EPA regulations. Add the fact that riders were increasingly turning away from two-strokes for more civilized four-strokes and the writing was on the wall. Intended to commemorate Yamaha's racing success, the Yamaha RD400F Daytona Special ended up, instead, as a monument to the two-stroke motorcycles that defined an era.
This rare machine, built for the US market only and resplendent in Yamaha's racing colours of white and red, is a true collector's piece.
Interested parties should note that this motorcycle has been registered with a personalised number plate which is being retained. A new registration has been applied for.
Interested parties should note that this is a library image. Pictures of this motorcycle will be added shortly.
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