4 1968年、その後)

"In some Grand Prix races during 1967 we experienced a somewhat mysterious big end bearing problem. After an analysis of the oil it was found that this trouble was caused by a minute contaminant in the oil. Installation of a special oil filter between the oil tank and oil pump solved the problem."
"Connecting rod big end bearing: In the development of an engine with high rpm, durability of some engine parts became problem. The most important problem was durability of the connecting rod big end. To maintain a long life of parts at high rpm, it is apparent that sufficient lubrication is essential -and strength to withstand stress is vital.
  Shortly after the season began we experienced rod big end bearing failures. We decided that bearing in the retainer cage was too heavy and caused subsequent high inertia loads. The bearing cage was lightened by reducing the crank-pin diameter and by using a lesser number of needle rollers. In this way cage strength was not reduced.
  But a new trouble occurred - flaking on the surface and breakage of the crankpin. It was found that this failure could be corrected by changing the location of the oil nozzle and using a crank pin of special material. Also, the thrust washers installed on both sides of the big end were removed so that frictional heat caused by thrust force from side play at the big end was eliminated. The movement of the big end was controlled at the small end through wider wrist-pin bosses so the rod could not touch the crank web. After these modifications were made we did not encounter any trouble with the big end throughout the Grand Prix series of 1968"

"Transistorized ignition system is well known, but we tried using two different methods of electrical pick-up to work as the spark trigger. One utilized magnetic force and the other an electric wave. Development of these two methods was completed, but there were no observed performance differences between them. Therefore, the electric wave trigger was adopted simply by reason of its shorter development period.
  The mechanism of pick-up is as follows: between two pick-up plates, which face each other over a gap of 2mm, a specific electric wave is constantly emitted. A change in the wave is caused by passing a blade with a special shape between these two plates, and this change is utilized as the igniting signal."

 左は1973年に再公開されたRD05Aだが、右下に写ってる円形のものが「pick-up」で、4組の「pick-up plates」が90度間隔に配置されている。そして「blade」も写っている。





TT オランダ ベルギー イタリア



  A E TT N B AE CZ Fin  U I 有効得点
READ   8   6 8 6 8 8   8 46
IVY 8   8 8   8 6   8 6 46

5 現存するマシン

  1973年に1台のRD05Aが再公開された。その後、しばらく表に出なかったが、1983年に開館したフジ・モーター・ミュージアムに貸し出し展示され、このミュージアム が閉館するとヤマハに戻った。そして、1998年のCentennial Classic TT(アッセン)、タイム・トンネル(筑波)、鈴鹿ヒストリック



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