SRX PISTON QUESTION...?

JAMIE

JAMIE

New member
WILL ALL SRX 440 PISTONS FROM 76-80 BE INTERCHANGED...?JUST ASKING SINCE THE 8F2 STUFF IS GETTING ALITTLE HARD TO COME BY...?
 

DUDE, A BIG NO. ALOT OF DEFFERENCE. FIRST LET ME SAY THE 78-80 SRX TAKES SAME PISTON AND RING WITH THE LARGER WRIST PIN AND CRANK ROD DIA. 21.5mm . NOW THE 77 SRX HAS SMALLER WRIST PIN / CONECTING ROD DIA. WHICH IS 18.5 mm , SAME AS 76 SRX. BUT, 76 SRX TAKES DEFFERNT RING AND PISTON HAD HIGHER DOME FOR HIGH COMPRESSION CLOSER TO WHAT GPX USED. moral of the storie is it all depend on what crankshaft your running !! 3:16 (tony)
 
thats not correct the 78-80 srx used a 20 mm wrist pin the 76 and 77 used an 18 mm pin. there are spacer cup available that will allow you to run an 18 mm pin in a piston designed for a 20 mm pin they fit over the ends of the 18 mm pin and have a 20 mm diameter to fit the 20 mm wrist pin bore. using some of these it would be possible to use the 78-80 wiseco SRX pistons in the earlier 76 and 77 srx's they could also be used in a GPX if you bored it .5 mm over as the gpx uses an 18 mm pin also.
 
Looks to me like you are both correct. One person is talking connecting rod size, the other is talking piston pin size.
 
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thats not true the 18 mm pin goes with a 22 mm con rod bearing bore its an 18x22x22 bearing. the larger 20 mm pin should take something like a 20x24x22 bearing where the wrist pin bearing bore is 24 mm.
 
JAMIE, RUN RIGHT OUT AND GET A FREAKING SPACER CUP. THAN YOUR FINE TO RUN ANY YEAR SRX PISTON WITH ANY YEAR CONECTING ROD!! SORRY I DID NOT MENTION THAT. GUESS I AM NOT CORRECT. !! 3:16 (tony)
 
i only meant that the dimensions for the wrist pin sizes you listed above were not correct Tony. your are correct in that there are differences between the different years. as for the pin cups ill have to look around i forget who makes them ill get back to you. if all else fails they could be machined faily easily.
 
AHOOD, I AM SHURE JAMIE GOT MY POINT, IF HE NEEDED EXACT SIZES, I COULD OF PULLED THEM OUT FOR HIM. JAMIE , YOU DO WHAT YA WANT. BUT IF ITS MY MOTOR, I AM GETTING THE RIGHT STUFF PER YEAR RIGHT FROM YAMAHA. I AINT, RUN,IN NO SPACER CUPS OR WISECO JUNK !! AND WISECO PISTONS WERE JUNK IN SRX,s !!
 
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