So I cut my new chain a couple links too short. Good news it with the adjusters almost all the way in the chain fits and the slack is within spec.

However this is by far the shortest the wheelbase has ever been, and I'm started to notice more headshake (or maybe my recent events have made me more keen to it).

Anyways I guess my question is how short is too short for the wheel base? I believe the amount of threads showing on each adjuster bolt was 3.8mm on each side. Would a couple links (2 inches at most) make that much of a difference in how the bike handles?

My forks are just above the top triple and not quite flush so I could still push them through a little more to compensate.

Head shake is pretty normal. Suspension setup?. Run the forks flush and get a steering damper if it bothers you. I run a Scott's. A Nichols triple clamp allows you to push the forks down lower.

Aphex without doing anything else to the bike the next time you go for a ride take -5 to -6 clicks OFF of the FORK rebound adjuster. Free up the rebound and see if the head shake lessens or goes away. Don't change anything but the fork rebound to a 5-6 click less.......sounds dumb but try it and then make all the fun of me you want. I can take it.

SD#1

I soften'd mine just one click back on all settings (just for comfort) but it has also stopped 90% of the headshakes.

Not making any suggestions since I"m not qualified to do so, but by shortening the wheelbase via the chain tensioners, you are theoretically lowering the rear a bit and raising the front, correct?

I would guess that sag and preload would need to be looked at again front and rear after a geometry change like that...but again, not suggesting anything just musing out loud

Also, I assume you have chain slack measured when you're sitting on the bike, wheels on the ground? I've been told chain slack can look fine without the rider and be way too tight once riding it = restricted swingarm travel = bad news

Why not just adjust according to the manual?
7 mm of slack between the chain and swingarm when pushing the chain up with the bike on the sidestand. Has always worked fine for me.

That's exactly what I do.

can't argue with the official KTM recommendation since I have no data to refute it...gotta ask "is the suggestion for 7mm of chain slack based on research focusing on bike performance? on longevity of parts? both?"

Chain tension (like suspension setup) is set while the bike is static, but does the measurement technique take into consideration the dynamic application? Heavier riders, greater need for shock/swingarm travel will be part of the equation. If there's wiggle room in suspension settings and tyre pressures why not in chain tension?

If chain tension is set via the owner's manual and seems taut (whatever that means in mm slack) when the rider sits on it, the suggested 7mm of chain travel may limit swingarm travel, shock performance, and traction is all I'm thinking. Take it with a grain of salt