1975 Yamaha RD350 Pistons size

[4schizzle]

Good Afternoon,

Thanks for all help, this forum is a great resource. 

I wanted to see if anyone could identify if this is a stock bore piston out of a 1975 Yamaha RD350.  On top of the piston has a 6 with a forward pointing arrow then 14.   And just below the highest part of the dome of the piston it is stamped with 979.  I added a pic in the attachments.  Thanks for the help.

4schizzle

[m in sc]

yup. stock bore.

should be a 64mm bore piston.

[rodneya]

The 979 is the piston measurement. 63.979mm. They matched it up with an appropriate sized cylinder at the factory to get clearances in spec.
Mine was stamped 974

[4schizzle]

yup. stock bore.

should be a 64mm bore piston.

Thanks

[4schizzle]

The 979 is the piston measurement. 63.979mm. They matched it up with an appropriate sized cylinder at the factory to get clearances in spec.
Mine was stamped 974

Thanks

[4schizzle]

yup. stock bore.

should be a 64mm bore piston.

Any recommendations on what type of piston's to buy?  Stock or what aftermarket brands?

Thanks,
Brian

[m in sc]

my preference is pro-x

[rodneya]

Por X banshee pistons. Just cut the little tang off the skirt.
OEMCycle usually has great prices on ebay or their site.

[4schizzle]

Por X banshee pistons. Just cut the little tang off the skirt.
OEMCycle usually has great prices on ebay or their site.

Does it matter what year banshee?  I am guessing it doesn't matter the year.    What tang do you need to cut off.  I am new to the RD's. 

Thanks for all the info. 

[rodneya]

Pistons are all the same. Banshee motor did not change from 86 to 2008 or so.
The piece circled in red should be cut off  to the same level as the pieces beside it and filed with a bit of a champfer or it may catch the intake port

[m in sc]

https://www.economycycle.com/shop/yamaha-rz-350/engine-related-yamaha-rz-350/pistons/prox-piston-kits-sold-each-yamaha-rd350400rz350rd350lcrd350ypvs-all-years/

[4schizzle]

Pistons are all the same. Banshee motor did not change from 86 to 2008 or so.
The piece circled in red should be cut off  to the same level as the pieces beside it and filed with a bit of a champfer or it may catch the intake port

Got it thanks. 

[4schizzle]

Hello all,

I am still waiting to get my cylinders/heads back from powder coater.  I split the cases and replaced all the seals.  I checked the crank and bearings and they feel/sound good and no play.  I was just looking at the pistons and wondering why the right side cylinder piston skirt has so much wear/slap/scratches.  There was some scratches in the cylinder but i am not sure if the cylinder was scratched or it was aluminum from the pistons.  I am getting the cylinders bored so i am guessing it does not matter.  I never heard the bike run but it turned over when i got it. 



Thanks again for all the help.

[4schizzle]

Front side of piston. 

[m in sc]

it got hot and expanded too much.