Front fork tightening bolt

Reassembling my front forks and have to ask what holds the fork lock cap and piston when you tighten the bolt? The fork lock cap right at the bottom has a big groove in it - is this to clear the 17 mm drain bolt that protrudes into the tube? My drain bolt was bent when I removed it.

Ok - after reassembly I can answer this myself. The groove on the end cap that sits on the very bottom of the tube is to allow the long drain bolt to protrude into the fork and in effect locks the cap so that the piston shaft bolt can be tightened. When assembling the fork make sure that the drain bolt is installed then make sure that when the bottom cap goes in that the bolt meshes with the groove.
If you do not do this the cap will sit on top of the bolt and be damaged.
If you leave the drain bolt out and install the cap there is every chance that the groove will not line up with the bolt hole. This means that when you tighten the drain bolt it digs into the cap, distorts its angle in the bottom of the slider tube and gets badly worn needing replacement. The previous owner somehow managed to do this.
Hope this helps those stripping down the right side VF1000R fork.