On the project XR250 the front forks aren't that great so toying with conversion to XR400 as I have these set up nicely on my 400. I have the 400 tree, but the stem seems 15mm too long. Is it possible to drop the xr400 stem through the bottom clamp - is it interference fit and can be got off with some heat ? Or do i just make up a spacer ? I saw elsewhere i need the XR400 front wheel bearings and spacers and axle - that seems straight forward enough, plus the caliper mounts are at the same centres. The issue i see if the handlebar stop as these are different. I could drill/tap the XR400 lower clamp and insert a bolt - would this work ? I saw someone say, don't bore out the 250 clamp - has this been tried and proved a failure as it only needs 2mm taking off ?