SE Cast Flat Tops in a 95" - How Far In The Hole?
#11
#14
07 and up engines routinely have the pistons .009 down, earlier models were about .002. I agree with Dewey that it does not matter if you mill the cyl bottoms or step mill the heads to get the quench right, as .030 is the goal but a couple of thousands either way is not going to make or break the build. I do disagree however in that if you just shave the heads to get cc correct, you cannot use a thinner head gasket to get quench corect. What you are shooting for is to get the piston to within .030 of the quench shelf of the head, and if you can do this through using a thinner head gasket, it works just fine for a street bike. So, if the piston is .009 down in the hole, then a head gasket of .021 would be ideal to get the .030 quench.
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07 and up engines routinely have the pistons .009 down, earlier models were about .002. I agree with Dewey that it does not matter if you mill the cyl bottoms or step mill the heads to get the quench right, as .030 is the goal but a couple of thousands either way is not going to make or break the build. I do disagree however in that if you just shave the heads to get cc correct, you cannot use a thinner head gasket to get quench corect. What you are shooting for is to get the piston to within .030 of the quench shelf of the head, and if you can do this through using a thinner head gasket, it works just fine for a street bike. So, if the piston is .009 down in the hole, then a head gasket of .021 would be ideal to get the .030 quench.
Early 07's had some horrible deck heights, some as far as .017 down the hole. My early 08 was less than .003 in the worst cylinder.
But that was irrelevant, be cause you change all that when you change the pistons and jugs. After bolting on my jugs and pistons, my .003 turned into near .009 and I had to cut the new jugs. One had to be cut a few thou more than the other.
Ended up with zero deck height, used .030 head gaskets and 82 cc heads.
Perfect quench with a perfect compression for my cams. 10.4:1 which yielded 206 ccp.
#16
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Parallel to the wrist pin, both sides at the same time if you can.
Somebody has to rotate the real wheel while you hold the solder in the hole. Smash the solder then put a micrometer on it.
Subtract the head gasket thickness from your measurement.
If you get it right, it'll give you a good idea if you are in the ballpark or not.
I remind you, my BB kit was .009 down the hole.
Well worth checking!
If you have the heads off (you said you were going to at some point), you don't remove the jugs to measure deck hight the more accurate way.
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The solder measurement will give you balpark numbers on a relatively "clean" cylinder but with any carbon build-up you may get numbers that are way off the mark. Only accurate way is to pull the heads, remove any carbon, bolt the cyls down and then take your measurements.
Thanks for the replies. I'm gonna talk with the mechanic that did the 95" install and see if he can recall approx. the piston position in the cylinders. I don't want to have to remove the cylinders at this point.