[TheSteve]

When I got my bike it wasn't running, so I've never ridden a carbed katana. So I have no idea how much improvement there is over stock.

[il_ragazzo]

well just the lack of a choke is reason enough for me to do it...and no air fuel mix to adjust when i go to Yosemite.

[TheSteve]

Well i think the hot start issues are now officially a thing of the past. A few days ago a buddy and I went on a ride up south mountain. He was on his cruiser (and hasnt been riding as long) so I was going a good bit faster than he was, so at the end of each lap I shut off the bike and waited for him. Clearly having just raced up and around a mountain the engine was probably as hot as itll ever normally get, but it was still happy to fire up on the first crank after every time I let it sit. For those who havent been following, it used to be impossible for me to run errands on the bike because after sitting in traffic then parking it would never start again till it either got jumped or cooled off. So now only one thing remains.....finding a 750, 1100, or 1200 engine for the beast and swapping it in.

[ericej2344]

I just won a set of GSXR throttle bodies. Just wondering where did you get connectors for the injectors.

[il_ragazzo]

Well i think the hot start issues are now officially a thing of the past. A few days ago a buddy and I went on a ride up south mountain. He was on his cruiser (and hasnt been riding as long) so I was going a good bit faster than he was, so at the end of each lap I shut off the bike and waited for him. Clearly having just raced up and around a mountain the engine was probably as hot as itll ever normally get, but it was still happy to fire up on the first crank after every time I let it sit. For those who havent been following, it used to be impossible for me to run errands on the bike because after sitting in traffic then parking it would never start again till it either got jumped or cooled off. So now only one thing remains.....finding a 750, 1100, or 1200 engine for the beast and swapping it in.

yes!!!

[TheSteve]

Mine actually came with the subharness for the throttles that had all the plugs for the injectors, tps, etc. Ill look around the garage to see if it shares plugs with any common cars. I do remember the tps being a strange looking one so you may be best off trying to find the subharness off a gsxr

Heres one: http://cgi.ebay.com/ebaymotors/01-03...Q5fAccessories

And a cheaper one: http://cgi.ebay.com/ebaymotors/01-03...Q5fAccessories

[ericej2344]

Thanks for the quick response. I hate to dig deeper in my pockets, but at least I know what I'm looking for.

[TRUEBLUE]

Excellent write up!!!!
I'm doing the same just on a RF600. Great Information!!!!

[jamesbm1001]

just a question...

If someone was wanting to do this but in a slightly easier way, and was willing to pay extra (without buying a gsxr), could they use a gsxr ECU and wiring harness and have it remapped? Also, this was probably already covered, but does the Mega squirt you're using controll timing?(i.e. does it deliver the spark?) I'm by no means an electrical expert and would definately opt for the easiest way possible to do this...again without buying a different bike.

[TheSteve]

Actually both of those were answered already lol. You might be able to get away with a remapped ECU, but every single sensor has to be in place and showing correct values. It really depends on how much you can remap on it. You'd need to change the temp values since these oil cooled motors run so much hotter. You'd need to find an ecu that uses dual coils like the kat, unless you fit the new quad coil ignition from whatever bike to the katana engine. basically everything would have to be a perfect match, and even then it may be easier with the "generic" MS setup thats not expecting anything so specific.

MS can do timing, however I didn't bother. On a kat with its wasted spark setup it wouldnt be too hard to do either. I may change mine someday if I run out of other projects. There are benefits to be had for sure.

[jamesbm1001]

just clarifying, what does "wasted spark" mean? I have a pretty good idea but want to make sure.

[TheSteve]

Wasted spark is an ignition system where the two "paired" cylinders share an ignition coil. So the two cyls that have a common TDC spark at the same time, with one being TDC on the compression stroke and the other TDC on the exhaust stroke. Its relatively easy to control since you only need a crank trigger wheel which the Kat motor already has.

[jamesbm1001]

would there be a downside to using an intake manifold with individual injectors and a single throttle body? I'm reasonably farmiliar with these systems from owning a honda del sol and tinkering around under the hood of that thing. I was just thinking that it may streamline the process. Any thoughts?

[TheSteve]

Honestly that was the route I was going to take before I found out how similar the GSXR throttles were to the kats carbs in sizing. It'd make it much easier to tune and you'd never have to worry about syncing. It'd be much easier to turbo as well if that's something you were considering. If you can weld and fabricate you could probably make a pretty effective intake manifold. You could also tune the powerband some by making intake runners of different lengths and seeing what gives the most favorable torque curve. The only possible downside would be that its hard to match the flow and throttle response of the indepent throttle bodies.

[jamesbm1001]

those are the reasons that I was considering making my own, I have the tools/experience, and then ease of use. With a big enough throttle body you should be able to match flow of the individual units. What is the size of the gsxr throttle bodies? (mm's) I know I saw it somewhere but can't find it again.