70 hp Yamaha Questions

[XpressHJ]

Ive got a 70 Hp Yamaha 2 Stroke, I know what im going to do motor wise, but what can be done lower unit wise? I really think the 2.33 ratio is going to end up hurting my performance. Are there different gears available? Or should I just go to a smaller lower unit and make a custom mount to bolt everything up?

[FrenchPhil]

Well considering the UIM record for that motor is 102.5mph there probably lots to be done...

[Ballistic]

1.87 gear lowerunit from a 48 or 55hp bolts right on.

[XpressHJ]

Thank you sir!

[lcp]

i,ve been told the uim 70ces t850 ran 1.73 gear ratio.or they run 1.86 ratio stock 48/55 ratio.correct me if im wrong.

[Hounddog]

Found this old thread that mentions the 102 mph record. I hope the picture is not the record setting boat. That does not look like it could run that speed. Not even a nose cone. Were you allowed to run an oversized skeg?

[Fast Fred]

looks like it has a low water pickup on the hull

[DuckLn]

Canada vs france?

[FrenchPhil]

No, its not the record holder. This pic was shot during the Rouen endurance race a few years back - before the yammie 70 was outlawed.