Piston size

[Yamaha]

What does PISTON (STD), PISTON (OS 0.25), PISTON (OS 0.50) mean?

 

I understand it piston oversize, 1st , 2nd or 3rd. but what is the mm of it?

 

Its for xr400.

 

if i will to get piston (OS 0.50), how much will i need to hone/bore?

[kurarensu]

think like ur stock is 32mm in diameter, then the (OS 0.50) will be 32.5mm? not really sure hees.. jus a tot

[ulysses_sc]

What does PISTON (STD), PISTON (OS 0.25), PISTON (OS 0.50) mean?

 

I understand it piston oversize, 1st , 2nd or 3rd. but what is the mm of it?

 

Its for xr400.

 

if i will to get piston (OS 0.50), how much will i need to hone/bore?

 

I see that you are rebuilding your engine again. 0.25 means 0.25mm oversize. 0.5 means 0.5mm over.

 

If your existing piston is 0.25 over, you will need to bore and hone the cylinder if you get a new 0.5 over. You will need to give the machinst (hopefully one who knows what he is doing) the piston and block for him to know how much to bore.

[Frank y]

And if you go REALLY OVERSIZE, you have to ensure that the cylinder walls have sufficient thickness left - to prevent cracks and coolant leaks during extreme working conditions, cos cylinder bores do not remain perfectly round at high temperatures.

[CoStar]

yup, if u dunno a place, there's one at junction of pahang st and dunlop st. 10 bucks.bored mine there when it jammed.