GX340 vs GX390

[yalipito]

According to the Honda specs they both have the same bore and stroke. What makes them rated at different power levels? Head cc's?

 

[trinik7597]

It's like a gx200 vs a 160 ... Bore is the same but stroke is not .. chamber volume has nothing to do with the HP rating .. only displacement

 

[yalipito]

They both show 389cc, 88mm bore x 64mm stroke.

 

[trinik7597]

They have changed a few things on the 340 in the past couple years so I don't know why spec reads the same on them

 

[trinik7597]

The 340 used to have a 82mm bore vs the 88 of the 390 .. so I am assuming if the bore size is now the same that the difference would be in the stroke .. there has to be a difference in CC's for a power rating though it has never been based on the head

 

[ole4]

I remember reading this on bobs. They changed the 340 and it is now same size think carb may be smaller but not sure of that.

 

[yalipito]

How would a gx390 compare to a briggs 305 if they were built similar? I know that displacement is a big factor. Powerwise, would they be close?