Piston for Yamaha 20a model 648

raczekp1

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Hi.
i'm looking for oversize pistons for old 20 hp yamaha. piston dia is 64 mm. i need oversize piston,is it posible to get one?
 

Scott Danforth

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And on the contact page they have a 10 digit number that you can call
 

raczekp1

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i send a mesage to wiseco to ask if there any chances to find fiting piston.
if not i'm redy to push out old sleevs and do the new ones and push back.
old pistons looks fine.no scoring.
in Poland i can do rings for this piston, but old rings have thin layer( maybe 0.10 mm) of chome or something in this kind.yamaha made in 1980's have 67mm pistons and ther is no problem to find std( 1 set is 25$) or oversize(
2 x piston kit is 62$)
 
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raczekp1

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its hard to push out old sleevs. Friend from singapur found me oversize pistons +25 size, number 653-11635-00 for +0.25
 

boscoe99

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Do you know the part number for the standard size piston that is used in your particular motor?
 

raczekp1

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std size is 653-11631-00-96 or 653-11631-00-98
oversize piston +25 is 653-11635-00,
 

boscoe99

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Could not find anything by the piston number. Can you provide the complete identity of your motor? It is possible that your model motor, or anything similar, was never offered here in the USA.
 

boscoe99

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The parts catalog is nice to have but what I need is the complete engine identity. Should be on a data plate on the left hand clamp bracket. Begins with the number 6.

Where are you in Danmark? My sister lives in Kobenhavn. Good beer there. Great bread.
 

raczekp1

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now once again.
i could not find new pistons for this yamaha 20 hp with cylinder dia 64 mm. I tryed even to push out old sleev from the blok but i stoped press out when force reached 15 000 kg .
but i got bad powerhead taken from 25hp model yamaha with exhoust over the prop.
cylinder dia is 67 mm and pistons will fit to my blok if i rebore them to 67 mm. This is way how to find oversize piston.
crakshafts in 20 and 25 hp model are the same.
 
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