I'm surprised this topic has not been discussed anywhere in here. It was common knowledge back when our bikes were new: never use the fork lock. I suspect many owners unlocked their ignition butterfly years ago and don't even remember where the key is anymore so locking the fork is a moot point.
Nonetheless, the hot tip was to never use the factory fork lock. It was known to jam and while I have never seen the cause of the jamming explained, it was something I only flirted with once. I parked, locked the fork for the 15 minutes I was going to be inside a bike shop. I came back out and the lock would not release. I fumbled and fiddled with it until it unlocked and I vowed to never (EVER) use the fork lock again.
So a week ago I'm picking up another addition to the stable. It belonged to a friend of Doug Hoffelt. Doug didn't have the time or space for another Super X and I ended up taking it on. I'll share that elsewhere. As I followed Doug through his shop, gathering bits for the bike, he apologized for "the bike only has one key--I don't know if it had two or not." Somewhere in there I mentioned something about the fork lock and "You know to never use the steering lock, right?" In mentioning this to him, the gods on Mount Olympus decided to have some fun.
As we were rolling the bike out of the shop, the fork was having problems turning to full-right. Doug mentioned, "Yeah, I think the steering head bearings are going to need some attention." Seemed odd to me but, whatever. Add it to the list. Got it home, up on the lift, fork dismantled. Damn, the fork is still binding up to the right. It won't even come close to the stop. I get the bars off, the top plate and even the nut on the steering crown. It was still not turning to the stop and the fork also wouldn't come out of the frame.
At that moment the sickening realization set in: the fork lock had jammed some time in the past. The bars were forced to overcome the lock. It now had the destroyed lock bound up in the steering head and I wasn't getting it apart without drilling the lock out.
To save others in the future, who may stumble onto similar, or didn't know about not using the lock:
This is the position of the key when it's in the locked position. When unlocked, the key slot is parallel to the steering neck.
The lock is held in place by the screw coming in at a 90 degree angle on the right. It's a small grub screw down in the hole. It tightens into a pocket on the lock. Once installed, a breakaway screw is put in behind the grub screw to prevent removal. The secret to removing the lock is removing the broken screw and then the grub screw. I mistakenly thought they were #10 screws and drilled too small of a hole. I also didn't trust a screw extractor at that size so I relied on drilling the hole and trying to pick the threads out (didn't work). I could see the hex of the grub screw but, couldn't get things to back out.
For future reference: the hole in the frame is 1/4-20. I very accurately located the center drill but, I only drilled 0.160". It needed the pilot diameter for 1/4-20 which is a 0.201". Get it right and a tap will chase the threads perfectly. After my ordeal, I was able to chase and save the threads.
How the lock works and what fails:
This is a picture of a new fork lock next to the scallop cutaway in the fork neck. When the fork is locked, the scallop turns 90 degrees and blocks the fork stem from rotating. The problem is: Illinois Lock didn't make this out of tough enough material and there ain't enough of it. It bends--easily--too easily.
This is what the lock looked like that came out of this stem.
No, I am not installing a new lock. I made an aluminum plug on the lathe. I'll tap that into place and forever block the hole. Depending on how that fits, the screw hole may get a new grub screw or it may just be filled with RTV sealant. No more fork lock for this bike.
If you think you'll just drill through the lock, let me warn you in advance: I went through a number of solid carbide drills that grabbed onto hardened pieces in the lock and snapped off. One got jammed inside. I was then reduced to a couple of 1/4" 3-flute carbide endmills chucked up in a die-grinder. Both of those were completely destroyed (about $30 each) but, they did the job. After the root canal of the lock, a large dent pulled was screwed into the lock with a few other screws jammed around it. That managed to get the lock free. Save yourself the work: carefully drill the break-away screw, get it out and remove the grub screw the proper way.
Or better still: don't EVER, EVER use the fork lock.
