My stock 400f bars finally arrived and just finished changing out the higher, more swept back bars that the previous owner put on her for the stock bars. The more forward riding position is great for this bike, and it really cleaned up the top lineπ. Very glad I got the pre-drilled Honda bars, they mate well with the original switch housings.
Here's what I did, which should work for you if you are putting on bars where the switch housings and master cylinder will end up being closer to the frame than they were when you started. If you are going from flat bars or clubmans to bars with more rise and/or rake, don't be surprised if you will need new and longer throttle and clutch cables or brake line. I didn't need to shorten my throttle cable or brake line as there was enough room to re-route them and avoid kinks but keep them close enough to the frame to avoid rubbing and keep them out of harms way.
1. Disconnect the left and right switch wires at the main wire harness at the mass of couplings beneath the tank. Didn't need to remove the tank. My original wiring harness is in good shape, so there weren't any wiring surprises (ie, two different wire colors/patterns going together) to keep track of.
2. Unbolt/unscrew the left and right switches and master cylinder and carefully detach the housing from the bars. Only one half of each switch housing fully detaches from the bar. The half that remains is connected to the wires, so treat that VERY gently. You don't want to weaken or break those wire connections in the switches, unless you want another project. The switches and master cylinder will hang free of the bars just fine.
3. Loosen and remove the 4 bolts that couple the bars to the upper fork yoke. With the switch housings and master cylinder free of the bars, you can now pull the bars far enough to the left so that the throttle assembly will come free of the right side of the bars.
4. Here's where it helps to have another person around to help. Grasp the wires below where they attach to the switch housing and gently pull while your helper pushes the wires from the other direction. DO NOT grasp the housing to pull the wires. The more bend in the bar, the harder it is to pull/push the wires through it. Good idea to loosely wrap the loose connector ends together with electrical tape before pulling them through the bars - less chance they will get hung up when pulling/pushing them through the bars.
5. Inspect the shrink tubing around the wires. You may have to replace the shrink tubing (Mine was in great shape, just wiped it down with WD40).
6. Put some lube on the shrink tubing (WD40 worked fine here) and push the taped connector ends through the pre-drilled holes near the end of the bars toward and through the center hole. 400f bars have so little bend to them that this is pretty easy compared to anything with a sharp bend to it (i.e., clubman bars). Keep pulling until the housing is in the correct position. The pre-drilled Honda bars have a hole for a pin inside the housings, so you don't have to measure/guess the correct position for the housings on the bars. This is a big timesaver.
7. Slide the throttle assembly over the right side of the bars, then loosely reattach the switches.
8. Loosely reattach the bars to the upper fork yoke.
9. Remove the bolts holding the gauge plate to the head lamp/turn indicator frame. You don't have to detach the gauges, just the plate that hold them to the frame. You are going to be bringing the switches, throttle, brake & clutch handles, and master cylinder in closer to the frame from where they are (used to be) located, so you will probably need to adjust how your throttle and clutch cables and brake line thread around the steering head. Having the gauge platform disconnected allows you to move these cables, lines, and wires so you do not end up with kinks or binds in your throttle and brake line (a nasty surprise on the road).
9. Once the switch wires, clutch and throttle cables, and brake line are repositioned, reattach the gauge platform.
10. Reattach the left and right switch wires to the main wiring harness. These are simple couplings that push together, and reconnect every wire that you disconnected earlier.
11. Make your final bar, switch housing, and master cylinder position adjustments.
