Changing to a heavier fork oil and making the klunk go away makes me think the forks are topping out; especially when you consider that Triumph increased the spring resistance starting in '05. I grew up on dirt bikes and may be a little spoiled, but this is the most miserable fork I have ever ridden/owned. Well, within the last 20 years anyway. I am going to try some heavier springs and Infinity sub tanks, if I can find a place to mount them.
That might make a more compliant front end, then I'll probably hate the rear shock. I don't really ride this one off road, I just want it to suck up ugly pavement without sending a useless jolt through the bars.
Others have stated there is some sort of valve in the forks to reduce dive when braking hard. I can't see how a valve could differentiate between a braking force and off road riding, smooth compressions, berms, etc. What happens when braking over stutter bumps or square edged potholes?
Can someone explain this valve further? Until then, I'm going with lighter oil = topping out.