700 triple low compression 1 cylinder


New member
Feb 1, 2023
I’ve got a 1999 venture 700 triple with 13,000km on it. Checked compression last season and was 125ish on all 3, it ran perfect all last season. Just checked compression this season before winter and the middle cylinder was reading 113psi and 2 outer were still 125psi. Once torn apart I noticed the middle cylinder nikasil coating was chipping off in some spots near the top so I thought that was the cause for low compression.
Just installed 3 new SPI pistons and rings with a new used middle cylinder, new gaskets and everything. Now after the new top end both outer cylinders are 127psi and middle is 110psi. I Checked carb boots for cracks and checked the crank seal by spraying some brake clean but all seems fine. Does anyone know what my issue could be?