Building a KiwiKat

[Anonymous]

Hello Guys. I am new to the forum and thought I would share my progress and snippets of interesting info with you all. I am building a Katana 1100 special using a JMC rear swingarm, GSXR1100 USD forks and GSXR1100 front and rear wheels and brakes etc. The JMC swingarm was supplied by JMC to fit a standard Kat, so is 1/2" narrower at the pivot area than a standard swingarm. This is due to the 5mm strapsteel mount each side that comes with the conversion. The swingarm comes complete with a Spax shock. I have linked the top of the shock to a GSXR750 top mount and have made up my own mounts and bracing to accomodate. I used 2" x 3" box section and turned up dowels for the 4 mounting bolts of the top shock mount. I have cut away the factory top bracing on the Kat frame and widened the frame rails by means of a vehicle scissor jack. I widened the rails an additional 6mm to gain tyre and frame clearance for the 530 chain. I am running a GSXR1100 5.5" x 17" rear wheel with the old GSX1100 rear sprocket carrier which has the sprocket face machined 3mm closer inboard than the GSXR item. I have positioned the shock mount so that the exact centre stroke position of the current shock is at the exact centre swingarm position of the standard Kat 1100.

 

[Anonymous]

Here is the cross spar that I built to strengthen the frame rails and to mount the GSXR750 top mount to. I made this a tight fit while the frame rails were spread apart 6mm more than standard. I kept the swingarm pivot bolt tightened to maintain the integrity of the frame holes. The swingarm bolt itself is a little short now by 6mm. I will either use a longer bolt, preferably a drilled axle bolt of the same diameter, or machine the nut a liitle thinner in the lathe. I added the chain slipper, because the chain travel entered the bottom area of the box section and I wanted this as strong as possible.

 

[Anonymous]

Here I have mig welded the cross spar in place and also the triangular gussets on the side of the frame tubes. I have used the chain slipper to good advantage here to lace it together to the inside of the side brace.

 

[Anonymous]

Mono Shock mounting

Mono Shock mounting

All welding is now completed and the alloy GSXR750 shock mount and the Spax shock are now in place. The welds on the spar face have been dressed and filed back so the new GSXR mount can sit perfectly flat. I had to drill the GSXR aluminium mount eye bolt hole out to 1/2" to accept a high tensile bolt for the top shock eye. I have added an X section brace made out of heavy wall 3/4" tubing between the cross spar shock mounts and the 2 frame rails to add additional rigidity to the frame. The 2 bends in the frame rails behind the side covers under the tank are the Kats weak points.

 

[Anonymous]

I had to raise the battery box to clear the new fangled mono shock. It all fits with the original battery and about 1/4" clearance under the seat. Here I used the standard Katana 1100 battery box and the original 2 rear mounting holes on the frame. I have just used longer bolts and aluminium spacers of approx 3". I had to make up a new front mount, I just drilled and tapped a piece of 1" x 1/4" strap steel and welded it to the nearest tube. I got a hold of another battery box and cut off the 2 rear mounting ears and welded them to the bottom of the box that I am using to give it additional strength and stop it wobbling about. I also made up a new mount at the bottom of the battery box directly below the original top one to locate the bottom side panel mount that holds the rectifier and fuse box etc. I have used a 1991 GSXR1100 fuse box assembly. The old Kat one has seen better days and was a bit goosed. The GSXR one bolts straight on and the Kat plug will fit, but the wiring convention is different for the lights. I am using a modified GSXR1100 wiring loom and switchgears up front.

 

[Anonymous]

Looks good. You have some good ideas. The shock mount looks plenty strong. You found a place for the battery, that's good. Try to keep some details in mind like shock adjustment accessability.

I'm in the process of finishing up a similar project. Good luck and feel free to PM me if you need to know how to not do something. :lol:

 

[Anonymous]

Hi Swanny, yes I agree. I was a little annoyed at the placement of the damper adjustment on the Spax shock, and may possibly change it for another unit later down the track. It should have been turned around 90deg either way to make it more readily accessible. This is a pic of the assembled swingarm unit. You can see the spacers at each side of the swingarm pivot, a triangular gusset to brace the frame under the output sprocket and an additional heavy duty mount I have welded inboard for the rear engine mount bolt. Note that I have welded inside the original mainstand mounts. These are only welded on the outside as standard because the mounts are only in contraction holding the bike up on its stand. For there new task of anchoring the rear suspension they are now mainly in expansion mode, so must be strong enough.

 

[scotty]

I wish you lived next door

lol first i thought it said KAWI-kat

 

[Anonymous]

Hi Scotty, so do I. I am flying solo on this project. We don't have too many guys building old Kats over here. I would love to do this sort of work for a living.

This is the side profile of the rear set up. I have drilled a hole under the swingarm pivot and spun up and welded in a dowel to locate the torque reaction rod for the rear caliper. I am using GSXR1100 brakes all round. The rod is running about 2mm clearance from the 180 section tyre, about the same clearance as the 530 chain.

 

[Anonymous]

I'm not sure how big around the swingarm pivot is on yours, but on mine it's pretty big (2001 GSXR750). It comes darn close to the back side of the engine cases. After I get it running and do some sorting out I may fab some different mounts to move the engine forward 1/4" or so.

I reinforced the bottom shock mount with an additional piece of channel across the frame. Your top mount looks very rigid however.

 

[Anonymous]

Side view of the frame bracing. I concentrated on beefing up the drive side of the frame. The top bracing plates are made out of 8mm plate, you can just see a piece of heavy wall tubing going across the frame between the first and second holes at the rear. The rear sets in this pic are Impulse 400, but I found these were unsuitable and have since changed to GSXR1000.

 

[Anonymous]

I had the frame straightened and the caster set back a fraction to 26.5 deg to quicken the steering a little before I started . Here is the front section of the bracing. I have triangulated the steering head from both above and below. I have also gussetted the top frame rails and down tubes. I tacked it all in place and made sure that I could get the engine in and out (rocker cover off) before final welding. I spun down a piece of heavy wall black tube to fit in the standard front engine mounting plates. This is a real cow to fit when the engine is in place because the engine width is wider than the frame mounting width by about 1/4", but beefs up the lower frame tremendously. I made the 2 pieces of solid 9/16" rod into a vee shape directly under the steering head and between the 2 middle pipes for ever more bracing.

 

[Anonymous]

I have just completed the peg mount fabrication and have set the front peg centres in exactly the same position as the original Kat. (For my size and style of riding the Kat positioning is perfect). It was quite a major exercise getting the pegs positioned just right. I used the plastic lid off an ice cream container to make a template first before cutting and filing the steel ones. The front peg sets are GSXR 600/750/1000 items and the rear are Yam YZR250 that I have shortened and redrilled the mounting brackets on. The front and rears actually look like matched pairs, so I am quite pleased with that. I wanted to use the "corncob" type pegs and not rubbers. I used a Honda CBR250/1000 rear brake master cylinder on the GSXR mounting. The spacing for the mounts and the bore size is the same, but the threaded part for the hose bolt is at the top of the cylinder rather than on the inside. This gave me more clearance to mount the peg set more inboard, otherwise the brake hose and banjo bolt would have spaced the assembly out about 15mm from the frame. I used the GSXR1000/750/600 fluid reservoir hose and it fitted perfectly onto the old Katana cast reservoir!! The hose to the rear GSXR1100 caliper is a GSXR1100 FRONT hose. I clamped the banjo ends of the hose in the vice between 2 flat washers (so I didn't ruin the sealing faces) and contoured the pipes by hand to make a better fit at both ends.

 

[Anonymous]

The front end was a real mission for a few silly reasons (mainly getting dicked about by the subbies) but it should have been easy. The legs and triples are GSXR1100 WP/R/S. These are the longest legs in the GSXR range. I pulled the forks apart and had 80mm oversize inners made and also the damper valves extended the same amount. I wanted to preserve the same ride height and cornering of a standard Kat. The finished length of the forks from the top of the outer (not including the adjuster housing) down to the axle centre (unloaded) is 845mm. If anyone else is contemplating doing this conversion I would advise that you go for a 90mm extension to have a little more to play with. Mine is at standard ride height, but I would prefer a little more length just in case. You will note from the image that the bottom of the outer legs ride a little above the guard.
The triple bearings fitted straight into the GSX steering head no problem. I turned the lockstops off the GSXR lower triple because the lock swing from side to side was rubbish. I will fabricate new stops and weld them on soon. At the moment when the steering is on full lock and hitting the side of the petrol tank, the steering is not as sharp as a standard Kat. I think that I may possibly indent the tank a little both sides to allow a little more lock. It is certainly acceptable as it is but not quite right. Another problem to be aware of is that the forks will foul the standard dummy oil cooler because of the greater diameter of the legs. Any oil cooler has to be located further down close to the exhaust headers to have enough clearance, so watch this when you go to mount a cooler, especially if using an GSXR1100 powerplant with the larger cooler.
I trimmed a small amount off the top and bottom of the Kat beak to clear the forks and also had to modify the fairing brace a little to allow the bottom triple bolts to clear as they swing past.

 

[Anonymous]

This is the top of the Kat. I have used GSXR1100 M/N gauges. I had to pull them back to clear the flyscreen. The top yoke is annodised silver and the clipons are Red. (If you don't already know, annodising will not stick to castings, but it will if they have been polished. Billet is no problem. Aparently castings have a lot of silica to help break out of the molds, and this inhibits the annodising process). I may go to underslung clipons yet, but it seems quite comfortable as it is. The GSXR750 has underslungs but they are about 2 or 3 mm smaller id and not a lot of spare meat left for machining out to fit the WP/R/S upper legs. I had to grind back the ignition mount lugs under the top triple by about 5mm so the switch can clear the top of the fairing brace. The switch pokes up through the top triple a little, rather than flush, but is not really noticeable. I took the rev counter feed off the standard Kat ignitor. It works no problems. The forks in this pic are not the final ones fitted.

 

[Anonymous]

I have put the bike together with a Kat 750 engine temporarily while I build the 1260. I wanted to check that the suspension is working okay and that the chain is not going the rub anywhere. I had to do a quick jet job on the 750 carbs because there is no longer an airbox. I soldered up the airbleeds and drilled them out to about #90 and drilled the mains to #170 (1.7mm) and tried it up the road. The carburetion was not to happy but I got up to about 160kph alright. The suspension and brakes are really first class. It feels really strange being on a Kat but with softer springing and sharp brakes. The chain is not rubbing anywhere and the suspension seems to be doing everthing okay. The gearing sure is low geared though with the 750 lower internal ratios.

 

[Anonymous]

Sorry Guys, the seat just had to go. I hunted around and tried all sorts of rear fairings and seats. I saw someone on the net had fitted a CBR600 F4i unit onto His Kat. I went and borrowed one and tried it for size before purchasing and it really does look the business! I have had to bend the Kats rear tubes and shorten the CBR tailpiece by about 4". I have cut down an old Kat seat and have spent a few hours contouring it to front portion of the CBR tailpiece. Once the seat work fabrication work is all completed I will pull the bike down again for painting. I am still pondering about the engine though. I like the look and reliability of the GSX1100 but it is going to cost me over $2000.00 just to build a crank!! I can almost get an good oil cooled GSXR1100 motor complete for that. ?????

 

[Silvermachine81]

What city are you in?

 

[Silvermachine81]

Just get a GSX-R motor.
Reliable power and you dont have to buy all the things like ignition pickups, coils, Cams, worry about which pipe to get (cause there arent that many being made anymore) and some fit the GX but not the Kat.

I could go on forever but I to was shocked to see just how cheap you can pick up a GSXR motor for considering how many racing classes are using them these days, like those baby formula one style cars :x .

But maybe they are out of favour with the speedway guys now??

 

[Hoomgar]

Now this is cool! Way to build it buddy