Piston Clearence? Ring spacing? torq specs?

[Crazy lil punk]

1-What should the piston clearence be from side to side in the cylinder? I only had 1mm before it blew up.
2-Do the rings come properly sized for the piston, or do i have to fit them in the cylinder with out the piston and measure the gap?
3- what are the torque specs for the head, and the cylinder to the bottom end?

thanks alot

[machwon]

1 mm piston clearance would be huge and probably wouldn't run at all. Piston clearance is measured distance between the bottom of the piston and the cylinder bore. Pistons will taper and be smaller at the top to compensate for thermal expansion. Ring end gaps are measured in the bore and run .010-.012" on the R's. Otherwise a rule of thumb is .003-.004 per inch of bore diameter or is recommended in the piston kit instructions. 21 ft-lbs for the cylinder head, 28 for the cylinder base nuts.

[Crazy lil punk]

Originally posted by machwon
1 mm piston clearance would be huge and probably wouldn't run at all. Piston clearance is measured distance between the bottom of the piston and the cylinder bore. Pistons will taper and be smaller at the top to compensate for thermal expansion. Ring end gaps are measured in the bore and run .010-.012" on the R's. Otherwise a rule of thumb is .003-.004 per inch of bore diameter or is recommended in the piston kit instructions. 21 ft-lbs for the cylinder head, 28 for the cylinder base nuts.

okay, thanks

[wilkin250r]

The piston rings SHOULD come properly sized and gapped, but it's always a good idea to check them anyways. I have seen a few that were a little too small, and I've heard of people getting sets that were REALLY too small.

When the rings heat up and expand, they close that gap quite a bit. If the gap isn't large enough, the rings don't have room to expand. They push against their own ends, and then push outwards with a lot of force. They can damage the cylinder wall, or catch in the exhaust port.

Checking the ring gap is an easy procedure, and it avoids a potentially HUGE problem. It takes like 2 minutes, and skipping it could literally cost you thousands of dollars in repairs.

[Crazy lil punk]

Originally posted by wilkin250r
The piston rings SHOULD come properly sized and gapped, but it's always a good idea to check them anyways. I have seen a few that were a little too small, and I've heard of people getting sets that were REALLY too small.

When the rings heat up and expand, they close that gap quite a bit. If the gap isn't large enough, the rings don't have room to expand. They push against their own ends, and then push outwards with a lot of force. They can damage the cylinder wall, or catch in the exhaust port.

Checking the ring gap is an easy procedure, and it avoids a potentially HUGE problem. It takes like 2 minutes, and skipping it could literally cost you thousands of dollars in repairs.

my question is, whats the gap supose to be?