visual difference between reed and piston?

[eatmythunder]

is it possible to tell which motor is in this ski? The add says 550sx but the hull just says 550. sorry im new to this haha.

 

[Kohldanielzimmer]

That looks like an ~1985 js 550 with a piston port motor. You can tell the difference on the motors multiple ways, the simplest way (to me) would be to look at the intake manifold; on piston port motors (js 550) the intake manifold bolts to the cylinder, whereas on the reed motors (550sx) the intake manifold bolts to the crankcases.

From the pictures, I'd bet that is a piston port motor. However, many of these kawi JS parts are interchangeable and have been cobbled together over the years.

It should also be noted that the 1990 model of the 550sx is a piston port, but this clearly looks like an 84-86 js550.

 

[eatmythunder]

thanks alot! do reed motors have more power output over the piston or are they just more reliable

 

[restosud]

hull is a 86 and up with a piston port motor and a 85 and older exhaust pipe.
reeds have a bit more power but both are reliable stock.
both motors have manifold bolt to cylinder but manifold flange on p/p is vertical with 6 bolts total holding it.the manifold on reed is slanted where it meets the cylinder gasket area and has reed cages visible between the gaskets..
reeds have an alloy cylinder,p/p have a cast iron.

 

[Kohldanielzimmer]

hull is a 86 and up with a piston port motor and a 85 and older exhaust pipe.
reeds have a bit more power but both are reliable stock.
both motors have manifold bolt to cylinder but manifold flange on p/p is vertical with 6 bolts total holding it.the manifold on reed is slanted where it meets the cylinder gasket area and has reed cages visible between the gaskets..
reeds have an alloy cylinder,p/p have a cast iron.

Ahh it's been a while. Thanks for clarifying intake manifold orientation restosud.

 

[_evan]

for future reference here is a reed motor