honda 400ex bored to 440 and exhaust

[jcaldwell]

I rebuilt my engine a while back and I can't remember if it was a 11:1 or a 10:1 is there any way to find out what piston I put in the motor?  And what kind of muffler would be best for my bike?  Thanks

[Fox17]

do you have the reciets or papres on it? they should say. get a wb exhaust.

[jcaldwell]

if I had the papers I would know but I lost them and why a WB?

[derek330]

if you calculate your volume at top dead center and compare it to your volume at bottom dead center that will give you your compression ratio...   

ex.  if you had a 410cc's at bottom dead center and had 37.2cc's at top then you would have an 11:1 compression ratio. you could test the compression with a guage but you can not accuratly calculate the compression this way because it will change with different cams...