When I installed it, I had to re-cut the screw mountain because it was not cut properly.
Perhaps the Finish Spline is not being done.
The Flange bolt that comes with the kit is also wider than the body's seating area, so you need to replace it with a bolt that fits the seating area, otherwise the bolt won't go in straight.
Looks like you access from European region.
Would you shop at webike.eu.com?
