426cc kit for 400ex

[400exkid05]

i was wondering if anyone had problems with the 426 with just boring the stock sleeve out becaues it is so thin..

[underpowered]

had mine for well over a year now with minimal problems. Had the head studs pull out and blew a few gaskets, but with the cometic flexsteel gasket, have had no problems for about the last year, since last january.