400ex engine tap normal?

[gotahemi2004]

i got my cyclinder bore donce over to a 402 and when its cold its tapping like crazy but once it warms up seems to go away is this normal or should i be worryed ? guy at the shop adjusted my valves and it still is doing it..

[400ex men]

i think its nuthin

[mojoe2878]

its piston slap. my 440, does it too. some pistons have to have a larger side clearance than others and it can make them noisy at start up when the engine is cold, then when the engine and piston warms up it makes a tighter fit and the noise goes away.

[torqen2k1]

If you have a forged aluminum piston on cold starts they make more noise because it will expand to its operating temp.