1981 GSX1100 Katana Based Project

[garyS-NJ]

Hi Rob,

the Kat front guard has a U shaped pressed steel brace that sits inside the front guard and bolted to each fork leg. Without the four bolts/washers it weighs 800 grams. The rear sub-frame I have removed is the steel frame that secures the inner rear guard to the main frame, without bolts/washers = 260 grams.

Cheers.

The mudguard inside brace is actually a fork brace and so you might want something up there.

[Rob S.]

What's the current weight and running status? I must admit, at first I thought this was a pipe dream, but you seem to know what you are doing. However...

If it turns out that you personally weigh 400 lbs, a lot of us are going to be disappointed!

[dorkburger]

Been following along quietly with interest. Not sure if you have the wheels in hand yet, but mid 90s Triumph Trident wheels look suspiciously similar to later model GS wheels, but in modern sizes and likely lighter. There'd probably be some modifications involved with the brakes though. It's something I'd like to try someday.

[Shin-Ken 1074]

What's the current weight and running status? I must admit, at first I thought this was a pipe dream, but you seem to know what you are doing. However...

If it turns out that you personally weigh 400 lbs, a lot of us are going to be disappointed!

v
Hi Rob, sorry for the delayed reply, a very close friend passed away last week and have been involved with other matters, so the Kat project and logging on the Forum has taken a back seat for the last week or so.

Buddy if I weighted 400lbs I would be very disappointed as well, I do carry a few kg more than I should be for someone over 60, but only a few kgs.

Will post an update tonight my time. Dropped off the aluminium axle spacers today to be anodised and should have them back in 10 days.


Cheers,
Glen.

[Shin-Ken 1074]

Been following along quietly with interest. Not sure if you have the wheels in hand yet, but mid 90s Triumph Trident wheels look suspiciously similar to later model GS wheels, but in modern sizes and likely lighter. There'd probably be some modifications involved with the brakes though. It's something I'd like to try someday.

Hi Burger, thanks for your post, I am using 1985 GSXR 750 Slabbie wheels front and rear, these are light weight wheels and have a bead to fit tubeless tyres safely. Ditching the inner tube saves 740 grams on the rear wheel alone. I was also keen to run 18" wheels front and rear as these offer stability, lower the centre of gravity, less effort in the twisties. There is a reason Suzuki used 18" wheels front and rear for so many years in the Endurance Races. Also, they are a similar design to the 1983 SD Suzuki wheels so they will look almost factory, almost. Front wheel needed some serious work to make it fit a set of 1982 OEM Kat forks, the stock Slabbie wheel is to wide and has to be turned down in a lathe and have the hub machined to mimic the Kat hub for speedo drive and brake rotors.

For brakes up front going to try and adapt 2004 GSX750F calipers (lighter than OEM Kat) and for rear brake a 2005 GSXR1000 K5 underslung caliper. The rear brake is almost done and should be a winner.

Will post updates tonight.

Cheers,
Glen.

[Shin-Ken 1074]

The mudguard inside brace is actually a fork brace and so you might want something up there.

Hi Gary, yes, that OEM steel boat anchor of a fork brace is getting 86'd and replaced with a Daytona aluminium fork brace that weighs 330 grams including the 4 titanium bolts for the brace compared to the stock steel fork brace that weighs 800 grams not including the OEM 4 x steel bolts.

Cheers,
Glen.

[Shin-Ken 1074]

Hi Folks, the last week has been quite busy for me and resulted in almost no time spent working on the DW Project and no time at all on GSR. Some minor progress to report, the front and rear aluminium axle spacers and rear caliper torque brace are now away to be anodised, 10 days until they are back.

I did manage to sort out the rear brake components and although not fitted with a line and fluid it has had a dry fit. Rear brake system compared to OEM:

1982 SZ OEM steel rear brake pedal and bolt = 271 g.
1982 SZ OEM steel rear brake torque brace & bolts = 438 g.
1982 SZ OEM rear caliper, bracket and bolts = 1583 g.
1982 SZ OEM rear master cyl and res, no fluid = 433 g.
1982 SZ OEM rear brake rotor no bolts/lock tabs =2,170 g.

4,895 g.

DW 180 modified ally rear brake pedal and Ti bolt = 120 g.
Aluminium torque brace made in the shed = 59 g.
Modified 2005 GSXR1000 rear caliper and bracket = 1197 g.
Modified 2005 GSXR1000 rear master cyl & res = 218 g.
Aftermarket super light weight rear rotor no bolts = 550 g.

= 2,144 g.


DW 180 rear brake system comes in at 2,751 grams lighter than 1982 OEM Kat rear brake system, close to 57% lighter. That percentage will improve when the rotor bolts are weighed as the 5 DW180 rotor bolts are titanium compared to the 6 OEM steel bolts. When the axle spacers are back from being anodised and the rear end can be installed I'll give an accurate weight update. I don't want to make a mistake with the figures while there are parts being installed and removed to get them right so the tally will only be added to when parts are installed as a finished item.

Cheers.

[Shin-Ken 1074]

DW 180 rear master cylinder mount bracket after removing 180 grams.

DW bare frame 3 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Sometimes Swiss Cheese works.

DW bare frame 2 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Centre stand mount brackets lightened.

DW bare frame 4 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Frame taken straight from being garnite blasted and primer applied 30 minutes later. This pic is after hanging the frame before the primer was applied. Used 16 mm round bar so the frame could be pivoted to allow better access for painting.

DW frame primed 1 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Frame pivot position, still bare metal, primer hasn't been applied yet.

DW frame primed 2 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Frame back from the Painter, very happy with his work!

DW frame painted 1 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Rear master mount bracket minus the rust and chipped looks much better.

DW frame painted 2 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Centre stand mounts looking fresh.

DW frame painted 3 by Max Mutarn, on Flickr