I have been given a Falcon MTB. I've sorted out all its troubles but the front suspension fork is worn. When using the front brake the slack in the tubes make them judder. Is there anyway I can "solidify" the fork as I don't need suspension. Can I drill it back to front and put a bolt through or something like that?
As others said don't drill the fork, as others said go for a new/used fork they come by cheap in most countries when no suspension is needed. But if you still want to go DIY I will give you a couple approaches.
What you can do instead is to put a spacer inside the fork, that way it will have no travel avaliable. You will need something like Nilon or Lexan, as they have more plasticity than pvc it will only deform under load, so it won't crack and break. You can also use aluminium or steel.
About the "give" between the tubes and the legs that's tricky. You can slide a tappered rubber gromet. You will have to custom fit tho, but it should reduce the jugger.
The judder is likely due to slope between the fork stanchion and the bushings in the fork lower. Most solutions to make the fork “rigid” (i.e., no compression or rebound movements) will not address this tolerance issue, so in all likelihood the judder would persist after making the fork “rigid”.
The only real fix is to fix the tolerance issue by replacing the fork bushing, which may not be possible on low-end forks or cost prohibitive.
The best solution therefore may be to replace with an inexpensive rigid fork, as other answers have suggested.
You seem handy with tools. Your best fix is to swap in a different fork from a donor bike.
Things to look for in a replacement fork:
- Same stem mount format (threadless or threaded)
- Same steerer outside diameter
- Enough length in the steerer
- Same mounts for your existing brakes, whether they be disk or caliper or cantilever.
- If you need mudguard mounts - they're handy to have too.
Also closely inspect the donor fork for cracks and possible wear in bearing races. You may be able to salvage the lower headset race from the old fork.
You can use a fork from any material, steel or aluminium or carbon, but check its crash history first with the owner.
Where to source a fork? Try your local auction websites like ebay or gumtree or craigslist. Expect to buy the whole bike and pick off the bits that could be useful. You're unlikely to find a new fork with the right fittings for reasonable prices.
Last option is to buy a donor bike with rigid forks, and fix that up as well. Then your N is 2.
DO NOT DRILL HOLES IN YOUR FORKS
That would weaken them substantially and run the risk of them breaking under stress (e.g., when you hit a pothole). A broken fork will probably put you in the emergency room, and potentially the morgue if you're unlucky with vehicles nearby.
Hopefully, other answers will address how to fix your forks; worst case is replacement, which isn't crazy-expensive for rigid forks.