800 power valve piston difference?

[raduhydrotec]

Hi. Does anyone know the difference between the plastic power valve pistons OE #420854449 on the cylinders, and OE #420253255 on the cooling system? They both look the same. I think the aftermarket WSM #010-495-10 piston I purchased is only used for the cooling power valve and not the cylinder power valves. Is there a difference in the internal thread size?

 

[Tony dee]

On the water regulator the parts book calls it exhaust valve 420 253 255. On the cylinder it is called exhaust piston and the number reads 290 253 257. I forget if they r the same or even if the spring is the same. But those r the numbers and names in my parts book. The boys will know for sure.

 

[racerxxx]

The threads are different, smaller on the water reg vs. the RAVE valve.

 

[raduhydrotec]

Thanks a lot for the info. This site is really great!

 

[mikidymac]

The springs are different too if I recall.

 

[racerxxx]

Yes, they are

 

[racerxxx]

So is the cap