Jet kit for '95 Katana...is it worth it?

[tmk7c9]

I tried to find the answer on the search thing, but oddly, I couldn't find where this has been discussed before.

Anyways, I'm new to the forums, and I"m now a proud owner of a '95 katana. Picked it up cheap because it wouldn't start and the guy didn't want to mess with it, all I had to do was take apart the clutch switch and it fires right off. freebee fix, now I have a great running katana.

My question is, I have always installed jet kits on all my bikes, and it has always helped tremendously on drivability and power, (especially on my 1200 bandit). BUT on this old katana, on a test drive the carburation seemed so spot on, no dead spots, no coughs and sputters, perfect.....Has anybody seen a huge improvement because of installing a kit for this bike? also, everybody mentions the Ivans jet kit, but I can't find one for a pre 98 kat. do they still make one?

The only mods to the bike so far are a Yosh slip on system. I think everything else is stock, but after I rip it apart down to the frame for paint, I guess i'll know then.

Thanks for the help.

[Court93kat]

Hey... welcome to the boards. There is lots of info here, and people that can help you out.

Alright.. let's get started. I'll start with the exhaust. Do you have one or two mufflers? A '95 came factory with dual exhaust. If it only has one, then it's an aftermarket full system, not just a slip on. If you have a full system, more than likely the previous owner also had a jet kit installed. Otherwise it would run like garbage.

Ivan doesn't make one for the pre-98's. Nobody that is close to him will drop their bike off for about a month for him to work on it and develop a kit for us. I really wish someone would do that.

[tmk7c9]

We'll, thanks for pointing out the full system thing. I never noticed it before, but all the other kats have duals, I only have a single can, so I guess it is a full system. It got the rust sanded off and a fresh coat of 1400 degree ceramic paint today.

I have the carbs spilled all over my bench right now, and no, they haven't ever been jetted. Surprising I know, I can't figure out why it ran so well either. Maybe if I had spent a bit more time on it, I would have found some things I didn't like, I only rode it for about 30 minutes before I tore it all apart.

I'm in the process of re-shimming the valves right now as well. the intakes were pretty loose.

anyways, I guess I'll look into a jet kit and see what I can find. I've always been pretty impressed with the dynojet kits.


OH and one more thing, what are the differences between a 98+ and a pre 98 kat 600 motor? the blocks seem to be the same (so does my 1200 bandit), I really can't spot many differences between them, but in my 3 years as a bike mechanic, I can't remember ever diving into any katana. Thanks again.

[Court93kat]

You can get which ever jet kit you want, but I prefer the Factory Pro kit over DynaJet. With the DynaJet you will need to drill holes and plug them in the butterflies. With the Factory Pro you don't. But like I said, the choice is yours.

Differences in the pre-98 and 98+ motors? Well, there are some minor changes, like spark plug size, oil pan depth, header downtube length (related to oil pan) and the color of the motor. I am sure I am missing something, but that is what I can come up with right now.

Pretty much ALL Suzuki inline 4's that are oil cooled are the same size and look alike. There is a thread on here that talks about doing swaps for larger motors too. I know that the early 600 Kat motors were actually GSXR 750 motors with thick sleeves for the smaller 600 piston, but retained the longer stroke. The pre-98 750's and the 98+ 600's and 750's all have the shorter stroke and different connecting rods to correlate with the stroke length.

[The CyberPoet]

The stock carbs without a jetkit probably ran so well because the single-sided exhaust was probably a direct take of a 98+, and thus about the same pipe diameter and flow rates as the original dual-sided set-up.

The differences between the bikes/motors:
98+ gets a new oil pump system (with increases in oil volume over the older engines; the oil volume by '01 gets to 8.8 gpm), new oil-pump pick-up set-up, new oil pan shape/size, a different cam chain tensioner system (designed to reduce failures in the spring system), slight change in cam grinds from what I understand, different muffler. Carb sizing changes by 1mm on the 600's, as does the generation of carbs on both platforms (from mikuni BST to mikuni BSR); new carb system gets a single fuel feed line instead of dual lines from the petcock.

Ignition systems change at the CDI, a throttle position sensor is introduced at the carbs, the speedo sensor moves to the tranny output shaft (from the front wheel) and goes digital, and the gauge cluster goes from being three independent gauges to a full set of electronic thin-gauges on a PCB backer board.
Wiring harnesses change, with new connectivity for the changed CDi and gauges, plus proper molex connectors in places where the pre-98s had bullet connectors (such as for the fuel tank sender).
For the 600's, the bore & stroke remain the same, but for the 750's it changes (later models get a narrower bore and longer stroke for more torque emphasis and to share the same con-rod & crank with the 600's). Spark plugs for both engines change somewhere in mid/late 96 to a single 14mm plug from the previous 18mm plug.

Oh, and then there's the obvious changes in forks (dampening goes from three to four steps), dogbones (switch to straight design dogbones), fairings (bulbous), rear wheel size (ups in width to 4.5").
Rear brake caliper flips over the swingarm to now hang below the swingarm instead of sit above it.

Headlights get doubled, mirrors get a new form that's more stable at speed... I probably missed some stuff too...

You can find more specs at my Kat Tech Specs page here:

http://www.motorcycleanchor.com/katana/katana_tree.html

Cheers,
=-= The CyberPoet

[tmk7c9]

after looking at some pics, it's definately a full yosh system, there aren't any cross over pipes like there are on the 98+ systems. Just 4 downtubes that meet at the collector.

anyways, As I mentioned, it's down for paint, wheel bearings, steering head bearings, valve shims, carb clean and rejet...you name it, its torn in 1000 pieces in my garage. when I get it all sorted out, i'll let you all know how it turns out and runs.

I'll end up spending more on parts than I did on the bike, but thats half the fun of it I guess.

Thanks a lot for the help.

[Court93kat]

Have fun, and good luck with it.

You're absolutely right. Tearing it down and rebuilding is the fun of it.