90 yamaha

[mikeymike]

How much hp can you get out of a 90 yamaha with and all out build..
port job shave heads and all the goodies.etc

[champ20B]

How much hp can you get out of a 90 yamaha with and all out build..
port job shave heads and all the goodies.etc

Well, if its a two stroke you're referring to, then its a 70cid engine. Running on gas and just being a hot-rod build up, not adhering to any tech rules administered by a racing organization, you could probably get up to 150 or more. Many jet ski engines get about 1.75 to 2 hp/cubic inch, which are two stroke, so the same could possibly be found in a later loop charged outboard. Whether it will hold up to it is another issue though.

[Roflhat]

Think Hydrotec build them to 120hp reliably, I read that somewhere on here. They got the port map direct from yamaha

[Fast Fred]

the stock carbs are small..............

[Fastjeff57]

So are the reeds. The 40 twins up to 90 triples all used the same 6 petal reed cage.

Jeff

[88workcar]

Carbs are fine, don't waist you time and money on Hydrotech on a 90 Yamaha. 7500rpm and all the power you want.