Vintage EFI Katana Build (1983)
been working hard this winter (started last fall) trying to get my '83 katana road ready. As usual with extensive projects, I am behind.
My plan was to take a basket case 750 katana and build a 1260cc fuel injected turbo. I have the turbo and assorted parts as you will see when I post pictures but the turbo is out for this season due to time and money.
This build will be interesting to any old school GS riders out there. I am doing a ton of mods.
This is what I started with.
Here are some of the mods I am trying to accomplish:
straight cut gears, welded crank
custom braced frame
GSXR 750/954 honda front end
Bandit 1200 / GSXR 1000 rear end
Hilborn throttle bodies
simply digital systems EFI controller
Keyless digital ignition
usb charger for my iPhone
lithium iron battery
relocating as much electrical as possible out of site
the turbo is in the wings as I spend loads on the motor bits before buying the turbo. That will require more money and a new top end. That is why its next year.
I hope you guys find the build interesting and maybe even helpful.
Last edited by bobkat; 04-19-2011 at 12:15 AM.
Suzuki Katana frame
There are going to be a bunch of quick posts as I catch you all up to what I have been doing.
First order of business is to make sure the frame is straight. I did this with the use of a little geometry, and everthing checked out perfectly.
Next was stripping the frame of all the unused tabs to clean things up. Things like the center stand mounts, battery box mounts and other things that have no use on the bike. The battery will have a new hidden location since it is much smaller, lighter and more powerful than my stock battery. Would you believe 14 lbs lighter.
After frame clean up comes the planning for bracing, new mounts, under seat pan for electronics and fuel injection controller and so forth. The stock inner fender is just rounded plastic.
This is what I came up with.
For bracing I did a couple things:
Pic below: A triangle piece was put in for support and to hide some wires. Also, with the under pan I dropped it lower up front so the harness wires and others could run above and not be seen. I also used a piece of stainless steel tube .060" wall for the subframe. I used stainless cuuuuz, I polished it and it won't be getting powder. When done the frame will be powder nd it will be an accent polished piece as well as being some structural support.
I pondered over the quesion of keeping the stock pegs or moving to "rear sets"... well, after changing my mind 12 different times I decided that my main complaint with the stock set is the rear master being in the middle of my now nice clean empty space. So, I decided to relocate the master and use a GSXR master. I am going to have to make a custom brake rod being the distance to the rocker/actuator is longer now. I will turn one out of stainless steel and thread it so it covers all the threads on the GSXR push rod. It was a lot of work to move it 2"!!! the reservoir is now in behind the side cover. I will have a sight window for it as well (later pics) It only took two days to figure out a spot for it. These kats do not have much wiggle room under what little plastic is there.
With the bandit arm, and stock peg stay, the brake pivot needs attention. I cut 1mm off the inside boss of the pivot allowing the pivot shaft to move out board to help clear the arm. Also, needed to redirect the lower foot with the brake stop and trim some too. In the pic the frame is on its nose for those trying to figure out the picture. The return spring tab has to be reduced and the return stop pad had to be reduced as well to clear the arm.
I didn't do any cross bracing in the airbox area this time however, I did beef it up some with a removable bolt in chunk of aluminum. It is a solid piece right now but there will be some design changes to come.
1983 katana build beginning
After sending the frame to "tigger" it was a good time to sort out the fuel delivery. With fuel injection there are many considerations.
- fuel pump
-40 micron pre-pump filter, 10 micron post pump filter
-fuel valve/or not
-return line into tank
-fuel rail feed
-kats have no gas gauge and running out and switching to res is not an option
-fuel pressure regulator
-air bleed line from pump
-fuel pump amps, our 1100s have little to spare
Then I guess the consideration of how to get the tank off when needed without fuel dumping everywhere.
I am also considering a surge tank since the old tanks are so open and sloshy. I have had about 1/2 the experts line up on each side so I will make a decision and go with it.
It isn't plumbing it that is a problem so much as how it looks when it is done. My goal is as open a look as I can get without clutter. I have thought long and hard, spent many a minutes stairing, adjusting, moving, removing, readjusting and I think I have a plan.
I am going to use an sv650 fuel warning thermistor. I like those cuuuuuuz... they have to thermistors which will give me a low light and a critical warning light. They also thread in so I just have to weld a bung into the bottom of the tank, right beside my return line bung.
I am also doing a custom gas cap which may or may not be vented, so, aditional check valves will be needed if I go with non vented.
My fuel rail is 1mm from touching my side panels so I have two options:
1. modify the side covers to allow fittings in each end of the rail.
2. cap the ends, drill and tap the center of the rail running a "T" to incoming fuel and fuel regulator.
Here is the frame all welded up
Here is the new coil bracket I made to clearence the plug wires. The Dyna coils have a tendancy to ground arc to the stock coil mount area from the plug wire boot. The stock mount is just too tight to the coil.
Time to mount the bandit 1200 swingarm. Katana pivot is 16mm, bandit pivot is 20mm so a reducer bushing needs to be made. Also the bandit arm is narrower than the GS frame so they need collars as well.
When mounting the rear gsxr/bandit wheel (5.5 rim) I always use the GS sprocket carrier for this reason, sprocket sits closer to the midline of the bike so you have more chain clearance by the frame.
By doing this you also have to use the GS inner hub bushing. They are shorter than the gsxr. IF you use the wrong size bushing you will 1. not gain any chain clearance or 2. explode a wheel bearing from lateral loadiing.
I take the rubber cush out of the wheel when checking inner bushing fitment to eliminate the "squish factor". With the cush in the hub the carrier/bushing don't seat against the wheel bearing surface until the wheel is torqued down. You have to squish the cush to see if the bushing is the right size. That inner bushing has to mate against the wheel bearing or you may find yourself in a world of trouble on some lonely corner somewhere. The rubber cush is ONLY for rotational dampening.
motorcycle usb charger
Here is my iFuel. I hate being out on a ride with a dead phone. First vintage katana with one of these I bet. The usb is weather proof. Not on the market quite yet. Found a guy, how knew a guy, who worked for a company. The setup is a tricky combination of the guts of a car charger, the usb port and some circuitry to enable the 3GS to actually recognise the charger. It is far more complicated than I was expecting.
Last edited by bobkat; 04-21-2011 at 01:12 AM.
Holy moly............sweet project
oldskool suzuki rules
Looking good Rob. Next year's Turbo Kat is going to be a beast!!
I have a feeling this will be pretty hot when it's done, those old Kat's are pretty cool!
Much respect, that is a huge project. I've been down that road before and it takes 3 times as long as you think to do. Looks fantastic
so cool can't wait for updates
I built one similar to that couple years ago.
Originally Posted by Danke
There are more pics here.
Last edited by bobkat; 04-19-2011 at 01:20 PM.
Amazing work, do you still ride the yoshi katana rep.?
Originally posted by adamantium I'm going to type this slowly so that you folk can follow along.
Originally Posted by CHIA
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