Some words of advice from my Katana front end install:
The GS stem presses top to bottom. (some website mentioned it and I foolishly misunderstood / ignored). In other words, apply pressure at the top of the stem (where it mounts to the top triple clamp), and hold the bottom triple. Everything is much easier this way. There is a retaining ring which is not easily discernible that stops the stem when it is pressed into the bottom triple. I pressed from the bottom, and ruined my old triple, and had to turn down my stem to get rid of the part i screwed up. You have been warned.

Some good news:
The GS stem pressed right into the Katana triple, after about half an hour with the grinder taking off the old weld, and everything else just kind of fell into place. New bearings are recommended, although you may have trouble finding the seal that goes below the bottom bearing if you go with a non-OEM part. I ended up reusing the Katana one on a new bearing from Purvis bearing here in Austin (it was a Timken bearing, ISO 32006X) The X means it comes with the race, but mine was in good shape, and I didn't feel lime hammering it out.

The GS headlight brackets fit perfectly on the 41mm forks, although without the rubber bushings. This means there will probably be more vib to the headlight, as well as more wear on the brackets/tubes where they interface.

If you use the stock GS stem in the Katana triple, the ignition lock lines right up. You can mount the clip-ons above or below the stem, I like them in stock place.

A SV650 speed sensor is a direct drop-in replacement for the GS speedo gearbox - for those interested in digital speedo applications. It takes a 5v excitation voltage and outputs a square pulse (need to verify how many ticks per rev).

I'm sure you are all aware of the bad news - see dgyver's post on what needs to come from the Katana (but if you're lucky, you can get the whole front end off of eBay for less than 300).

First impressions:
The Katana front end transmits more engine vibs since it is not rubber-damped like the stock GS. So it is has a more tinny feel to it from the handlebars. But it also takes bumps much better, although I have yet to notice a significant difference from the three settings.

The brakes are a considerable improvement. The lever feels harder (you have to use the Katana master cylinder, since it's bored 5/8" as opposed to the stock 1/2". Failure to do so results in reduced swept fluid volume, and more stroke required for the same amount of pressure on the pads. A consequence of this may be finer braking control, but I didn't try it.)

What I noticed is that the pads are slightly more than half the size of the stock GS pads, but there are four of them, and they are squeezed by two four-piston calipers. The braking is better, but not awesome (although I have managed to hop the rear end up a few inches).

With the clip-ons, riding position is lower, seems more sportier, and yet somehow comfortable. I'm patiently awaiting carpal tunnel.

In the twisties, the front end seems a bit more stable, and doesn't tend to want to wash out as much when rolling on the throttle in a downhill turn. In the straight, dives faster(it may be the better brakes). but the dive is softer than it was on the GS. Speed bumps seem more cushy as well. I may have to rebuild these forks, they didn't seem to be in stellar shape - the dust boots disintegrated and the retaining ring for the seal seems to be coated in rust. Im guessing they may be low on fluid, although they feel okay when pumped.

That's all I got, hope it helps in some way.

Nice write up 

Thank you for your take on the katana swap. Would you be able to post some pictures ?

What I have found.... 97+ Kat stems are pressed-in and the previous years are welded, there may me others but have not been able to confirm. I have started an addendum to grind a welded Kat stem and use a pressed-in GS stem, just need to finish taking some pics. Not sure of all of the GS years that have pressed-in stems but 04+ are pressed-in.

The SV speed sensor has a larger ID (+2mm dia., I believe) than the GS axle.

If you want better braking... add s/s braided lines and EBC HH pads.

Quote from: dgyver on October 05, 2007, 04:06:21 AM
What I have found.... 97+ Kat stems are pressed-in and the previous years are welded, there may me others but have not been able to confirm. I have started an addendum to grind a welded Kat stem and use a pressed-in GS stem, just need to finish taking some pics. Not sure of all of the GS years that have pressed-in stems but 04+ are pressed-in.

The SV speed sensor has a larger ID (+2mm dia., I believe) than the GS axle.

If you want better braking... add s/s braided lines and EBC HH pads.

We gotta come up with a time to finish that.I'm bringing the whole F/E with me. 

The weld took quite a while to grind off (you have to grind until you see a clear distinct line), but i did not reweld afterwards. when I was pressing, it required about 2 tons of pressure to go in. I doubt there will be that much pressure even with the biggest speed bumps, and as long as the bearing tension is set properly, there is no slop, so the thing is pretty solid.

dguyver may be right about the id of the SV sensor, but it is the same thickness, and the wheel doesn't axially slop at all. come to think of it, the SV axle probably has 2mm bigger o/d, but as long as the thickness of the spacer (gearbox or sensor) is the same, it probably doesn't matter- just a bit easier to install the wheel because it does slop on the axle a bit. I'll have to double check.

today, i removed the ignition switch to swap it with my old one. this required some effort:
the service manual says to use a punch to index the screws and then punch around until it comes off. try getting a punch in there - the height of the boss around the sheared screw is a bit high for any of my punches. I ended up chucking each triple into a mill and coming down on each screw, until there was a clear line, just like with the triple. then a tap with a brass hammer on the switch, a small wedge and it comes clear off. the remainder of the screws came out without any effort. needless to say, they will be replaced by an hex-head.

personally, I think that if anyone steals bikes, they don't bother with the ignition - its probably four guys, 2 2x4's through the tires, and a minivan. and it's in pieces on ebay the next day (hope this doesnt happen to anyone).

i could see the ss lines doing some good. the pads I put on were organic, but with the way i ride sometimes, i can imagine having to replace them within a year. so next time . I used the stock setup for the brake lines, with the distribution block mounted on the bottom triple tree. I imagine with SS lines, you get two long ones, and it requires just a pinch more fluid in the lines.

i'm surprised noone's commented on my headlight mounting, I imagine people will ask questions when I post pics. as far as pics go, i gotta find my camera first, it's gone AWOL. As soon as I find it, i will post some stuff on my webspace and will link in.

another bit of information. the stock GS throttle cable is too long, and difficult to route with the clip-ons. therefore, turn handlebars all the way right, snap throttle open and rev to 5k (makes parking ... interesting), even though when handlebars straight there is just a bit of play in the cable. easy solution is to introduce a lot of play in the cable, but that sucks... so is there a shorter cable that will fit?

I had a similar problem putting clip ons on my standard front end underneath the throttle housing there is a small adjustment nut make sure it is tight and adjusted correctly. Mine would rev upto 3500 when turned full lock to the right took me about 20 min to realise what was wrong as the clip ons are not as wide as the standard bars, once I tightened it up it seemed to fix it. Though I'm yet to take it for a spin but so far its seems ok.
A good way to check is have the bars facing forward and give the cables a bit of a wiggle about to see which cable is causing the problem.
Hope that helps 

these are from when i first did my install . theres not a single problem with any cables being long or short , no ill effects turning the handlebars

why cant that exhaust be available in the states, god damn if that aint the sexiest looking pipe!

I was Wd40'ing and i got some on the downpipes , but since then and a tonne of polishing , there both nice and shiny!