Yamaha 4 stroke different horsepower

[8kgold69]

First I would like to say that this site is a great help and I appreciate the information that is provided by everyone.
Now I want to test someones knowledge.

Regarding Yamaha 4 strokes engines horsepower. After reviewing some spec sheets and reading some tech info, I notice that the 110, 160 hp engines have the same bore & stroke, 76 X 58 mm, 1052cc. The difference is the compression. The compression on the 110hp 11.4:1 and the 160hp is 11.9:1.
1)Is the difference in the head design?
2)Does Yamaha use the same block, crank, pistons and camshaft for both engines?
3)If you took a 110hp engine and swapped the head would that give you the 160hp?


thanks

[Technical Support]

Re: Yamaha 4 stroke different horsepower

The pistons are different thats what changes the compression. The head is also different but can be modified to work on a 140 H.O or 160 same engine. Just dont ask how to do it. The case is close to the same except for the water tubes in the side but they can be changed out. So just a head swap will not make the 110 into a 160. Hope this helps.