Building an ST1300 from the ground up.

Found the FI light lead. Turns out, it's a ground signal instead of a positive signal. Once I connected my test light to the positive battery terminal, I found the FI lead real quick. I started to tie up the harness, but ran out of electrical tape, so I started in on cutting the headlight brackets, but then my last cutting wheel broke, so I called it a night. Not too productive, but really glad I worked out that FI light issue.

Wiring is all done. I still need to weld the bung on the bottom of the tank, build the rear tank mount and organize the plumbing. I suspect the inline pump I'm using is providing too much fuel. I had planned on installing a Bazzaz at some point to tune for a vastly different exhaust, so I might be able to trim back the fuel to compensate for the increased pressure. If not, an Aeromotive fuel pressure regulator will be required.

Fun fact: A YZ85 front brake line is the same length as the clutch line. I had a braided Galfer line laying around and it just happens to work perfectly. Now I have three different makes in the mix.

Brake lines will be the last step before it's ready to go.

Thanks!

I already have the Z-AFM that I used in my RC51 and have installed the Z-Fi in other bikes. Let me know if you have any questions about your Z-AFM install or operation.

However...

If you haven't bought the Z-AFM yet, you might want to reconsider for two reasons. One, it's a lot of money and work to install for such minimal gains and improvements. That money could be spent on a dyno session at a good tuner. The other reason is because the Z-AFM won't tune below 3000 RPM. You mention wanting to smooth out around town and slow riding, so I'm only assuming you're not aware of the 3K RPM cutoff. The cells are there, but the Z-AFM will not tune in that region. If you're looking to smooth out that area, you're going to need to take it to a dyno anyway...

maybe...

Another option would be using a stand alone data logging wide band O2 and input the cell values in the Z-FI software manually. I still have an Innovate LM-1 that I used back in the day when I was soldering Megasquirts together for cars and I used that to do the sub- 3K region on my RC51. It's a pretty cool unit, albeit a bit clunky for bike use, but it will data log six channels (RPM, MAP, TPS, coolant temp and IAT on top of the O2) for up to 44 minutes. That's quite a bit of data to sort through, but it gives you a very precise picture of what is exactly going on every millisecond of operation.

Basically, I tuned the Z-Fi with the Z-AFM and then interpolated data for the values for the sub- 3K region. Then I loaded the Innovate software and the Bazzaz software onto a laptop and threw that in a back pack, connected the LM-1 (took about two hours because it gets semi- hardwired in), taped the unit to the tail of my bike (it's big!), and went for a ride. I rode around for about fifteen minutes around town, pulled over and plugged the laptop into the LM-1 and downloaded the data. Then I plugged the Z-Fi in and fired up that software. In the LM-1 software, I would look at the air fuel ratio at a certain RPM and throttle position and if it was lean or rich, I'd then go into the Z-Fi software and change the cell at that particular RPM and throttle position accordingly. Then I would clear the session from the LM-1, hit record and go ride around some more and repeat.

Between idle and 3K RPM and 0-100% throttle, there's 60 cells that need to be filled in. If that sounds like a lot of work, IT IS! I spent days looking at stuff like this:



If that's up your alley, I can help. If that's more than you're willing to bite off, then the smart money is on having the Z-Fi tuned at a dyno. Hope that helps and saves you some money!

Oh, one last thing- if someone tells you that you need to tune for different elevations, remind them that your bike uses a speed density EFI system, not carbs.

Finally got the headlight brackets cut out. They're just roughed out in these pictures. I'll do some finish grinding to clean 'em up and have them powder coated.





And here's one of the gauge cluster displaying the "max" feature. It'll recall maximum readings on tach, speedo and temp.



I've made up my mind on the exhaust; it's going to be mid mounted cans under the passenger pegs (the ones on the RC51 tail, not the OEM ST1300 passenger pegs). I know I'm taking the easy way out, but I really want to go ride this thing, and this will be the quickest way. I still have some unique things planned for this bike, but I want to spend a month or two shaking it down.

Now that the headlight and cluster are finalized, I put the tank, front fender, tail and seat on and the headlight and cluster really tied the whole thing together. I'm not going to lie... this is a bad *** bike. I've got a couple brake lines inbound and when they and the exhaust are done, it'll be ready for the first ride. I'll take pictures of the whole bike then.

I'm glad you're enjoying the thread so far. The headlight is from a Yamaha MT-03, and the steering damper doesn't connect to anything yet. I need to have a bit of welding done to the frame and when I bring it in for that, I'm going to have him weld a bracket to the front of the frame to attach the damper to.

Nice work! Can't wait to see it with all the body work on.

Here ya go, just for you. Pardon the mess; it's a work in progress.







I am going to lower the rear of the tail a few inches. I'm not a huge fan of the stink bug look, but more importantly, it's not comfortable to sit on. The earlier picture of me sitting on it had the tail propped up with a piece of wood and the seating position was neutral and relaxed. When I built the sub- subframe, I raised the rear a bit more than I should have, trying to take into account sag and a smaller rear tire. Yeah, that didn't work out too well. When I sit on it now, I'm pushing back against the bars to keep myself from sliding into the tank. It'll be an easy fix, though.

The exhaust is just mocked up; that's a spare testbed exhaust I have for my RC51, but it gives you an idea of what I'll be going for initially.

Lastly, the radiator fills in the hole between the front end and the engine quite nicely; I just have it off so that I can braze a bung to it for the gauge clusters coolant temp sensor.

Looks great. Are you going to make up covers to cover the frame/coils below the tank?

Mandrake, that's looking pretty awesome!! Any idea of what it will weigh when you're done?

WOW! I don't know how I missed this thread the first time around! Very cool to undertake a task like this re-imagining the ST.

I saw one reference to the damper. How did it function in it's original application? Is that bit mounted backwards? Apoligies if it was already explained. As I said I'm late to the party.

One end of the damper isn't attached yet. It will swing around towards the rear of the bike and mount to the frame.

Thanks, guys!

Coils will get longer leads and will be mounted under the tank somewhere.

Wet weight will be 512 lbs. (no, really).

Damper connects across. A bracket will be welded to the front of the frame for the damper to mount to.

Mandrake said:

Wet weight will be 512 lbs. (no, really).

Click to expand...

That's amazing weight savings!! Should handle like a dream!

Despite the fact that I'm not concerned about weight (it's going to weigh what it's going to weigh), I am keenly interested in seeing just how nimble it ends up being. I rode a stock ST1300 around town a few years ago and was very impressed with how light it felt- on par with a modern 600, I'd say. It is kind of crazy to think that compared to my build, you guys are carrying around the equivalent of an entire dirt bike in the form of fairings, panniers, seats, lights, instruments, brackets and gas. Even at the lowest preload setting, my rear suspension is at full extension and only compresses about 1/4" when I sit on it. Suffice it to say, a custom spring will be required and I may consider some Gold Valves after consulting with Race Tech. The fork springs are almost dead on where they need to be, so unless things feel real off up there, I'll leave them alone.

There are two aspects to the behavior of this bike that I'm very curious about. First, how the power delivery will be with a 30% reduction in weight and second, how the front end will work with the bike. As far as I can tell, this is the first fork swap ever done on an ST1300. All my research last year failed to turn up one shred of info surrounding such an operation. If someone beat me to that punch, they kept it to themselves. If you read back to some of my earlier posts, I discuss fork length, triple tree offset, tire diamter and the effects that all has on rake and trail between the ST and GSXR front ends. While the rake and trail are within what is considered safe and acceptable by my calculations, it's still uncharted waters and I have no idea what to expect. Hence, the steering stabilizer.

I don't think you'll have to worry much about the front end. I suspect it's not going to spend much time on the ground!

Good thing it has that enormous rear brake, then! Speaking of which, I had a friend who's an accomplished semi- professional stunt rider over a while back to take a gander at the project, and he was very jealous of the rear brake. He said he would kill to have something that big on the back of his stunt bike.

I felt special for a few minutes.

Tell your friend that it has linked brakes ... that'll get him over the large rear brake!

Mine doesn't have linked brakes.

The front brake line might be here by the end of the week and if it is, there's a possibility that a certain motorcycle of the V4 variety may take its first steps this weekend.