yz85 topend piston

[dd_moto]

hello i am wondering i recently blew up my topend and i took it into the shop today to get a piston of .052 1/2mm piston to fit in my yz85 2002 i discovered that my ring had scuffed up my cylinder bad enough that i need to sleeve it. i right now own a .051mm piston and i was wondering if they could sleeve it that small or if i have to buy a nother new piston.
Thanks for your help.

 

[Chili]

I'd get the cylinder repaired and recoated with nikasil instead of getting a sleeve.

 

[91-YZ250-Chris]

where do you live dd_moto? I was riding at a place near me in Laurel, Maryland called the pits and I saw a yz85 blow up

 

[dd_moto]

what does nickle coated do and will it make it .051mm and i live in st george

 

[dd_moto]

?

? or if i nickle coated it would it stay a .052 1/2

 

[Chili]

Nikasil is the coating on the cylinder wall it allows better heat transfer than a sleeve. The stock bore size for an 02 YZ85 is 47.5mm so I think you may have a 103.5cc big bore. Going to a sleeve and a smaller piston is going to reduce some of the advantages of the big bore setup.

 

[dd_moto]

yes i am awar right now it is a 107 sleving it will bring down to 103 unfortanetly i have to buy my parts by my self and i dont want to buy another piston.. And if i do sleeve it would i have to like rejet it or anyhting else?? like that