Sealth

I just got a Manitou Markhor fork installed on my 2017 Specialized Rockhopper Sport. It took the fork for its maiden ride, and I found that the headset was loose after the ride. I tightened up the headset bolt and stem at home. However, the headset feels really bad now, the steering feels frictiony and gritty. Typically this results from overtightening the headset stack, but in this case the stack really isn't that tight. In fact, it still feels like there's a little play in the fork steerer (much less than previously). Further, I noticed that the crown of the Markhor fork doesn't match the outer diameter of the headset tube. It seems like there is a small gap between the crown of the fork and the top tube which is possibly exposing the bearings to the elements.

What's going on here and how can I fix it?

trailangel

Take it back to whomever installed it.

bikeme

Did they put a straight steerer fork into a tapered head tube? Straight steerers are an older style that work only on straight head tubes. Around 2011 or 2012-ish (I think), bikes began to use tapered steerer forks/headtubes where the bottom of the steer is a larger diameter than the top (the top is the normal 1-1/8"). Another possibility is that a bearing race was omitted during the installation. Yet another issue could be that the stem cap is not able to fully seat on a spacer because the spacers aren't above the top of the steerer enough and it's bottoming out on the top of the steerer. Anyway, I'd go back to the shop that did the work. Hopefully this is some ammo for you to use.

Darth Lefty 

...and have them put the lower race on the fork

Sealth

I took it back, and they fixed it. I sounds like they just assembled the stack poorly. Basically there weren't enough spacers and one of the spacers was a tapered spacer when it should've been a straight spacer. I have yet to test it again though.

cobba

Some before and after photos might of shown what's happening and whether it's been fixed properly.