Yamaha 20 HP upgrade to 25HP

mardom61

Cadet
Joined
Aug 3, 2009
Messages
10
Hi, I have a 1994 yamaha 20 HP 2 stroke long shaft. It is the 395cc twin, 2 carbs. Apparently this motor was not imported to the U.S., I am in Canada. I have been reading on a few Australian forums that the 20 HP and 25 HP were the same engine with a different exhaust port. Apparently this is a very popular mod down there, they drill out the exhaust port and essentially they have a 25 hp for hundreds less. Some claimed that the dealer would do it for them, i guess warranty does not apply.

I did some research, both engines are 395cc, same bore and stroke and same carb settings. has anybody else heard of this mod? If i can get another 5 hp for cheap and safely then good, if not i will not wreck my engine.

any help would be great.
 

2Stix

Cadet
Joined
Aug 19, 2009
Messages
10
Re: Yamaha 20 HP upgrade to 25HP

Did you ever find out? I'm in Canada too and am interested in doing this
 
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