piston clearance

[justaviper]

I'v got the head off my 04 Viper S to send to benders for the mod for running pipes, and was wandering if anyone knows the correct piston to cylinder clearance? The pistons seem a little loose in there. I'm wondering if i should replace the pistons and rings. The sled has 3200 miles on it.

 

[mrviper700]

Spec: (.0026-.0028" )so about 2 1/2-2 3/4 thousandths, they can be run tight because they dont expand like a aftermarket one does, this improves piston stability in the bore and added ring sealing.

 

[justaviper]

Is it normal to have .010 thousands clearance with 3200 miles? Do you know the diameter of a new piston and the standerd bore size? If the pistons are worn that far i will replace them. But if the cylinders are worn i'll just replace the rings for now.

 

[tomseal6]

What kind of oil are you using??

You grass drag your sled? .010 seems like alot

 

[mrviper700]

Sure they can be sloppy with those miles, stock yamalube and or a dirty running enviorment(grass drags etc.) will show extra wear.

Stock pistons are 2.7143-2.7144" this is measured 10mm from the bottom of the skirt.

cylinder bore should be 2.7165-2.7171"

 

[tomseal6]

get youself 3 new pistons and a set of rings if its that bad.

Run amsoil interceptor synthetic, you and your motor will be happy..

 

[justaviper]

No grass draging, just normal winter riding. I was useing Quaker State Sterling TC-W3 oil. I'm now an AMSOIL dealer so i'll be useing that. I'm ordering new pistons and rings today. I'll measure the cylinders when i get it apart. Hopefully its just piston wear. Thanks for the help...Jeff.

 

[2ooosrx]

If you need pistons let me know...... I can help you!

Bruce

 

[justaviper]

I have an account at the local Yamaha dealer. But if you can get genuine Yamaha parts, get me a price.