Daytona Racers - Under Construction

Yamaha had began their racing and export market in the USA and as their racing classes developed, Yamaha chose to develop bikes specifically to suit this scene, in addition to their Grand Prix exploits. The most prestigious event in the US racing calendar grew to be held at Daytona, where Yamaha had participated in as early as 1961, where Fumio Ito and Yoshikazu Sunako raced the works RR 250's at the Grand Prix (Yamaha's first race in the US since the Catalina GP)..
In 1963 Don Vesco had won the 500cc class and Fumio Ito the 250cc class at the US Grand Prix held at Daytona, both riding RD56's and 2 years later Phil Read won the 250cc race.  But it was the AMA races at Daytona, especially the "200" had become the premier racing event which Yamaha dearly wanted to win. 
Above: Fumio Ito aboard the works RR 250 at the 1961 USGP Daytona.
Below: Chart showing machine development of YZ607, Z608 & YZ608 during 1967 & 1968
Yamaha had began their racing and export market in the USA and as their racing classes developed, Yamaha chose to develop bikes specifically to suit this scene, in addition to their Grand Prix exploits. The most prestigious event in the US racing calendar grew to be held at Daytona, where Yamaha had participated in as early as 1961, where Fumio Ito and Yoshikazu Sunako raced the works RR 250's at the Grand Prix (Yamaha's first race in the US since the Catalina GP)..
In 1963 Don Vesco had won the 500cc class and Fumio Ito the 250cc class at the US Grand Prix held at Daytona, both riding RD56's and 2 years later Phil Read won the 250cc race.  But it was the AMA races at Daytona, especially the "200" had become the premier racing event which Yamaha dearly wanted to win. 
Due to the different classes and of course politics (of which some might say supported home made firms) the AMA had evolved many different rules and homologation conditions compared to the European Grand Prix classes and indeed many of the other US races, such as the West Coast ACA and AFM events. This outlawed the use of Grand Prix developed engines and insisted that bikes should be based around over the counter engines derived from road available models, this included a clause that only 4 gears were allowed to be fitted in the "big bike" class.    
Therefore in 1967 (the same year the TD1C production racer was launched) Yamaha began to develop bespoke 250cc & 350cc machines to comply with the AMA classes to give the works team a competitive edge at Daytona. It was unknown at this time though, that these were also prototypes being developed for a new breed of machine which would render Yamaha ready for a new methodology of team support when they officially pulled their official race team out of the World Championship Grand Prix in 1969. 
The 250cc machine, officially code named YZ607 but also known as the "Works TD1C", "Daytona Racer" or "DS5 Racers", utilised the engine from the new TD1C, itself being a derivative of the road going YDS5. To gain an advantage, the engines were highly tuned and fitted with special magnesium carburettors and expansion pipes similar to the RD56, as well as improved ignition. Electronic ignition was intended and initially fitted but found to be unreliable, causing Mike Duff and Tony Murphy to retire in the 1967 Daytona 100 with standard type magneto's being substituted afterwards. 
Yamaha had began their racing and export market in the USA and as their racing classes developed, Yamaha chose to develop bikes specifically to suit this scene, in addition to their Grand Prix exploits. The most prestigious event in the US racing calendar grew to be held at Daytona, where Yamaha had participated in as early as 1961, where Fumio Ito and Yoshikazu Sunako raced the works RR 250's at the Grand Prix (Yamaha's first race in the US since the Catalina GP)..
In 1963 Don Vesco had won the 500cc class and Fumio Ito the 250cc class at the US Grand Prix held at Daytona, both riding RD56's and 2 years later Phil Read won the 250cc race.  But it was the AMA races at Daytona, especially the "200" had become the premier racing event which Yamaha dearly wanted to win. 
Due to the different classes and of course politics (of which some might say supported home made firms) the AMA had evolved many different rules and homologation conditions compared to the European Grand Prix classes and indeed many of the other US races, such as the West Coast ACA and AFM events. This outlawed the use of Grand Prix developed engines and insisted that bikes should be based around over the counter engines derived from road available models, this included a clause that only 4 gears were allowed to be fitted in the "big bike" class.    
Therefore in 1967 (the same year the TD1C production racer was launched) Yamaha began to develop bespoke 250cc & 350cc machines to comply with the AMA classes to give the works team a competitive edge at Daytona. It was unknown at this time though, that these were also prototypes being developed for a new breed of machine which would render Yamaha ready for a new methodology of team support when they officially pulled their official race team out of the World Championship Grand Prix in 1969. 
The 250cc machine, officially code named YZ607 but also known as the "Works TD1C", "Daytona Racer" or "DS5 Racers", utilised the engine from the new TD1C, itself being a derivative of the road going YDS5. To gain an advantage, the engines were highly tuned and fitted with special magnesium carburettors and expansion pipes similar to the RD56, as well as improved ignition. Electronic ignition was intended and initially fitted but found to be unreliable, causing Mike Duff and Tony Murphy to retire in the 1967 Daytona 100 with standard type magneto's being substituted afterwards. 
Top: The 1967 Daytona 100 Yamaha 250cc team. YZ607 mounted riders (Right to Left) #9 Gary Nixon, #10 Mike Duff, #21 Bob Winters, #22 Tony Murphy.
Above: Start line. #9 Gary Nixon, #10 Mike Duff, #21 Bob Winters.
Below: #9 Gary Nixon on his way to victory at Daytona.
Great Colour pics of #10 Mike Duff, Daytona. 
Lower: #9 Gary Nixon and #21 Bob Winters bike on the start line ahead of the 250 race at Laconia. Note the colour scheme change to a metallic red.
Bottom: Nixon wins at Indy ! 
 Knowing that the weakest link in the TD1 range had been the handling and braking, the new machines were to gain the featherbed type frame and brakes from the RD56, as the rules allowed (and perhaps because it had previously been used at the US GP at Daytona?). Forks on the 1967 YZ607 were TD1C types modified to accept the RD56's 4LS drum brake.     
The official riders for the YZ607's at the 1967 Daytona 100, were:
Gary Nixon #9            1st 
Mike Duff #10             Retired ignition issue
Bobby Winters #21   3rd
Tony Murphy #22      44th
Nixon and Duff both won their heat races.  80 race finishers.
Because of the AMA rulings about "Production based machines", Yamaha International, like all the other makes, went the extra mile to further "validate" their machines as well as using it to promote their sales by calling them DS5 racers in their advertising as well as stamping the machines with DS5 frame numbers, which of course they were certainly not ! 
Above: The 1967 Z608 350cc. Yamaha's entry into the big bike classes. R1 based engine with 1st gear removed, fitted in RD56 chassis complete with YR1/YDS5 front forks to comply with AMA rules.
Below: Tony Murphy's Z608 as road tested in Cycle World magazine) also still available in Cycle World book ON YAMAHA 1962-1969. 
The engine of this bike has survived in the US and will hopefully be seen back on track some time in the future. 
The new 350cc machines were Yamaha's 1st official entry into the larger classes and allowed entry into the Daytona 200; a much stronger class usually filled with 500cc Triumphs & BSA's as well as 750cc Harley Davidsons.  The 1967 model was code named Z608 and utilised the basic engine from the new YR1 model, with heavily modified cylinders, heads, pistons and gearboxes. This machine was also known as the "R1 racer" and again "Daytona Special". Because of the AMA rules, the machines had to have a gear REMOVED to make a a 4 speed machine, severely hampering the machines performance and putting a lot of extra wear and effort on the relatively weak clutch. The engines were equipped with 32mm (*TBC) remote float Mikuni -Amal carburettors, similar in style to the TD1C. 2 machines were initially built which also featured the RD56 frame and brakes as the YZ607, whilst the front forks used on these were modified YR1 units as the rule book instructed matching model forks and engine.  Again electronic ignition was trialled and replaced by magneto. As the final drive on the 350cc was on the opposite side, this necessitated a rear drum with an opposite action being employed.  
The official riders for the Z608's at the 1967 Daytona 200, were:
Mike Duff         19th 
Tony Murphy   18th
97 finishers. 
There was also one R1 based racer in Japan, ridden by Japanese champion K. Mimura, but it is unknown whether it was an official Z608 or a modified R1 machine, although from the pictures available it does appear to be a Z608.
Above: K. Mimuro on a Z608 R1 based racer in Japan, a successful combination. 
Below: From 1968 Cycle News magazine, depicting Mike Duff's 350cc machine, which appears to be his 1967 Z608 uprated to 1968 YZ608 spec, with new forks (early RD56 type but with external spring) replacing the TD1 components. The frame is clearly 1967 Z608 version as the swinging arm mount is not cut down as much as the 1968 version.
Four YZ608's were built for 1968, these featured engines based on the new YR2 model which were housed in a new version of the RD56 frame. Initially the huge 320mm magnesium 4LS front brake drums taken from the 1966 type RD05 V4 were fitted, these were used at Daytona but soon after replaced with the RD56 types. At least 2 of these brakes are known to have suffered cracking across the hub flange, but according to Phil Read the main reason for the reversion to RD56 brakes was that the air scoops on the RD05 caused the bikes to suffer a high speed weave (speed wobble).    
Front forks still maintained external springs, but were more like the RD56 type as opposed to the road units from the previous year.  The engines now featured revised cylinders fed by magnesium VM34 type monoblock carburettors. Ignition was again supplied magneto. The clutch was improved as were the gear ratio's to match the 4 speed restriction.    
The official riders for the YZ608's at the 1968 Daytona 200, were:
Phil Read #51               11th (throttle cable issue)
Mike Duff #28  
Art Baumann #71        3rd
Yvon Duhamel #5       2nd 
77 finishers.
Therefore, it was Yvon Duhamel (riding under the Fred Deeley Ltd banner (Yamaha Canada) & tuned by Bob Work , who became the 1st 2 stroke rider to finish on the Podium in the big bike "200". Both the Canadian and American team bikes shared the same pits.
 
The winner of the race was Cal Rayborn on a 750 Harley Davidson, but with this surprising result, the 350cc Yamaha's machines had surprised a lot of people and the industry, as well as slain a giant or two.
Top: 1969 British article showing the 1968 YZ608 and announcing the forthcoming TD2.  
Above: Period YZ608 detail shots (pics courtesy of Ferry Brouwer)
Below: Fantastic shot of Phil Read on the YZ608 before the Daytona 200 1968.
Bottom. Cycle Guide magazine front cover showing Phil Read in the pits having a throttle cable changed, dropping him to a still respectable 11th place.
Top: #5 Yvon Duhamel and Phil Read in action during the race. 
Above: Phil Read pitting to get his sticking throttle fixed.
Below: #5 Yvon Duhamel and #71 Art Baumann at speed lapping a back marker during the race.
Above: The 1968 Daytona 200 podium. 1st #25 Cal Rayborn 750cc Harley Davidson. 2nd #5 Yvon Duhamel 350cc Yamaha, 3rd #71 Art Baumann 350cc Yamaha.
Below: "Meet the Giant Killers" advert after Daytona, featuring Yvon Duhamel on his YZ608. Note, this picture was not taken at the Daytona 200 as the bike has the smaller RD56 brake fitted (as it still has now) Also note, Yamaha has listed the bike model as YR-2 to promote sales of the production road machine. 
Bottom: Daytona Report from From Yamaha News, Note that the YZ608 350cc is called R1 racer and the 250 YZ607's are called TD-1's in this context 
  
Above: Colour picture of a YZ608 in Cycle World report covering 1970 Daytona 200. This was Don Vesco's machine bought from Yamaha in 1969. Likely to be engine # R2-0006.
Below: Tuning data of the Yamaha YZ608.
As well as Daytona, the YZ608's were raced at:-
 
AMA National 100 Mile, Loudon, NH, June 16
Jody Nicholas    3rd 
Mike Duff            10th
Yvon Duhamel   RET
AMA 110 Mile National Indianapolis, August 4 
 
Yvon Duhamel  Ret 6 sec lead at lap 34, Ignition
Mike Duff  DNS Gearbox issue in heat race 
Art Baumann Ret after Heat crash
AMA 50 Mile Amateur, Indianapolis, August
Ron Pierce  1st 
AFM Vaca Vally, August 1968.
 
Art Baumann     1st
Mike Duff            2nd
US Grand Prix, ACA, Willow Springs,  October 1968,
 
Art Baumann    1st
Mike Duff          2nd .    
California International Grand Prix, Orange County, November 24th.
350 International Class
Mike Duff 1st
Ron Pierce DNF
Above: Factory mechanic Ray Martinez on Jody Nicholas' #58 YZ608, July 1968
The 250cc YZ607's were again pressed into service and uprated for 1968 with improved front forks similar to the YZ608. They also received VM3o-R7 magnesium monoblock carburettors, magneto ignition and Girling type rear suspension, other than that they were essentially the same as the previous year.
The official riders for the YZ607's at the 1968 Daytona 100, were:
Phil Read #51         3rd
Mike Duff #28        (crashed in rain whilst leading)
Gary Nixon #1        (crashed in rain whilst leading)
Art Baumann #71 
Each rider won their Heat Race.
AMA National 75 mile, Loudon, New Hampshire, June 16
Art Baumann  1st
Mike Duff         2nd 
Gary Nixon      8th
100 mile National, Loudon, New Hampshire, September 1968.
 
Gary Nixon     2nd 
Indianapolis
Gary Nixon    1st
California International Grand Prix, Orange County, November 24th.
​250 International Class
Ron Pierce 2nd
Mike Duff   7th
With the withdrawal of Honda from GP's in 1967, Yamaha decided to follow suit following year, having already developed the dominating YZ607 & YZ608 prototype machines.
Top: 1968 Daytona 100 #51 Phil Read on his way to 3rd place.
Above: #8 Mike Duff (AKA MAD 8) in action at Loudon, Mike finished 2nd behind Art Baumann on another YZ607. 
Below: #1 Gary Nixon, on his way to 2nd place, Loudon 100 miler.
Bottom: #3 Art Baumann crossing the line to take the victory at the Loudon 75 miler.  
These machines paved the way for the 1969 production racing 250 & 350cc models TD2 & TR2, which were more than capable of challenging all but the very best remaining works machines. Riding a TD2, Kent Andersson finished a very close runner up to Kel Carruthers on his works Bennelli 4 in the 250 championship whilst the 350 championship saw Silvio Grassetti (riding both works Jawa & private TR2) runner up and Giuseppe Vinsezi  in 3rd on TR2 behind Giacomo Agostini on the works MV Agusta. 
But at the end of 1969 the FIM banned multi cylinder machines in 250cc & 350cc GP classes in an attempt to reduce the cost of the sport for manufacturers and make it a more level playing field. Yamaha were in a commanding position.... The TD2, TR2 (and works YZ625 & YZ631) derivatives would go on to clinch World Championship titles with Rodney Gould 1970 250 World Champion, Phil Read 1971 250 World Champion (as a Privateer!) & 1972 250 World Champion Jarno Saarinen.
The era of production based racer dominated racing had begun. 

Picture Credits: Yamaha Motor, Kurt Fischer, Cycle News, Cycle World, Cycle Guide, Ferry Brouwer, Motor Cycle News, The Motor Cycle, Frank Camilieri, 

As well as riding, Tony Murphy and Mike Duff were also responsible for much of the development of these new machines. This was fed back to Japan and a revised model was built for 1968, code named the YZ608. 

© 2015 - 2019 Richard M Tracy. Proudly created with Wix.com

contact email : racebikes@outlook.com

This site was designed with the
.com
website builder. Create your website today.
Start Now