KH400's had a slightly more restrictive intake and made a couple of BHP less than an S3, which in turn had made a little less than an S2. My own KH500 was a bit gutless compared to the earlier models, until it was ported and expansion chambered, after which it ate clutch plates from slippage, even with stronger springs and an extra washer on each bolt. It was an absolute rocket for a while though. It did get tiresome with almost no bottom end pull below 3,000 RPM but I miss the fantastic sound these triples made.
