E series engine: straight cut primary gears?

[BrianZ]

I am overhauling an E series model 92 engine and found out that is has straight cut primary gears. Did the E engines ever come with straight cut primary gears or has someone added the gears afterwards?

[taber hodaka]

I am going to say no, they did not come with straight cut gears, someone added them. The least amount of noticeable horsepower comes from straight cut gears, just my thoughts. I have been wrong before. ----------Clarence

[dirty_rat]

The primary gears on the original Ace engines (including all the later ones including the Ace 100 B+) were a cast gear and not very rugged. If the engine was kept stock they seemed to work fine, but any extra power (even with an expansion chamber, etc.) and the primary gears would often break. So, many were swapped out for the Super Rat straight cut gears (which were forged and much stronger).

[hodakamax]

Even before the 93 Super Rat arrived the 914506R and 914003R straight cut gear sets were available as a racing part for Model 90 and 92. Many Racing parts before the model 93 had the 91xxxxR number as racing options like the close ratio 5-speed transmission. I sold many sets of straight-cut gear sets before the arrival of the Super Rat. Even the gear change ratchet for the model 93 was originally for the early 5-speed conversion set for the 90 with the number 912001R.

Max

[taber hodaka]

The ace 90 racing straight cut gears were used in the Super RAT. Part numbers that started with 91 were Ace 90 racing items made for the 90. Also the crankshaft and rod were 90 cc racing items used in the Super Rat. ------Clarence

[BrianZ]

Thanks folks! I suspected that the engine had been changed over to the straight cut gears, but having never seen the inside of an E series engine I was not sure.