Chain skipping - Bafang HD kit

[Tonerider]

I have a Santa Cruz V10 with a Bafang HD kit. On max boost, or throttle use in hi gear, sounds like the chain skips. Lower the gear and it stops. Is this because the chain is too long, or another issue? No amount of adjustment seems to help.

 

[sulu]

I think the chain is a bit long.

 

[jaxusa]

Chain stretches, cassette cog (11 or 12) wears. Use high quality non stretch chain. New high quality cassette. I modified the 11 tooth cog with a rotary carbide grinder to increase chain seat depth of the cog by approximately .020 to .030. No more skip. Increases cog life.