1981 GSX1100 Katana Based Project

[Shin-Ken 1074]

Tappet cover and sprocket cover installed today using aluminium and Ti bolts.

Tappet cover, gasket, breather plate and combination of ally and Ti bolts = 2,092 grams.

Running tally = 100,242 grams.


DW tappet cover Ti & ally bolts by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

Sprocket cover with aluminium bolts = 743 grams.

Running tally = 100,985 grams.

DW sprocket cover & ally bolts by Max Mutarn, on Flickr


DW sprocket cover & ally bolts by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

Installing the tappet cover reminded me to post a pic of one of the hollow camshafts installed in the DW 180.

OEM EX camshaft = 1,532 g.
OEM IN camshaft = 1,525 g.

Hollow EX camshaft = 1,314 g.
Hollow IN camshaft = 1,331 g.


The hollow camshafts were already installed when the engine was weighed prior to installing the engine in the frame so no change to the running tally.

DW hollow camshaft 1 by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

There is not much that can be done to the thin as paper fibreglass bodywork to reduce weight however, the Kat screen has potential to be lighter. The OEM polymer screen, brackets, bolts, grommets and screws add up to 474 grams. Almost half a kilo sitting up there in the breeze at the highest point of the Kat! This time swapping the steel bolts and screws for aluminium bolts wont cut it, the brackets and screen are where the weight is so the whole assembly needs to be replaced with something.

I have made cowls and panels using fibreglass so I thought how hard could it be to make a screen from carbonfibre? Turns out not as easy as I thought if you want a good looking end product. I now understand why carbon parts made by experts are expensive: material cost, vacuum molds, correct layup, temperature control baking to cure for maximum strength and most importantly, knowing what you are doing.

Anyway, after a couple of test runs, when the parts doesn't turn out right it is a test run isn't it?

OEM screen assembly.

OEM Kat Screen by Max Mutarn, on Flickr


The OEM screen on its own is 310 grams

OEM Kat screen bare by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

After a couple of total fails this screen turned out good enough to be used. Even before trimming the screen only weighs 155 grams.


DW screen 1 by Max Mutarn, on Flickr



DW screen 2 by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

Screen number 3 was salvageable and is now the Number One Banana. It turned out heavier than I would have liked, without a vacuum unit I had to apply the resin "Old School" with a brush and resulted in using more resin than optimal and made it heavier.

Carbon screen final version 153 grams including molding trim.


url=https://flic.kr/p/2p8kLmq]

[/url]DW screen 3 by Max Mutarn, on Flickr


Carbon screen bracket at 134 grams, again I used to much resin and it is pretty heavy.


DW screen bracket 1 by Max Mutarn, on Flickr


Gave the bracket some support at the base by rolling carbon around a paper tube. After the carbon had cured removed the paper tube.

DW screen bracket 2 by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

Finished screen in position on the cowl. Screen and bracket weigh 287 grams, 187 grams lighter than OEM screen/bracket but it was a lot of work for that 187 grams.
​

DW screen 5 by Max Mutarn, on Flickr

DW screen 4 by Max Mutarn, on Flickr

 

[Rob S.]

So the wind screen is opaque?

 

[Shin-Ken 1074]

So the wind screen is opaque?

Yes, the Kat screen function is to direct airflow up and over the rider at high speed and isn't designed to see through it so being opaque is no problem.

 

[Rob S.]

Okay, just don't take it too far. No carbon fiber helmet visors!

 

[Shin-Ken 1074]

Okay, just don't take it too far. No carbon fiber helmet visors!

How did you know that was the next carbon part for the project? A 40mm holesaw and two holes in the visor?

 

[Shin-Ken 1074]

Not happy with the screen weight, may have to revisit that?

 

[Shin-Ken 1074]

The Kat has rubber fins mounted on the lower side of the cowl and do two jobs, direct airflow to the engine and to look cool. Problem is they are a bit chunky and could do with a diet. No curves or tight corners so making the fins in carbon fibre was no drama. Force on the fins is minimal so I went with the lightest bolt option I could think of, nylon. Reduced the weight of the nylon bolts by drilling the shank and countersink drilling the bolt head.


These are the OEM rubber fins and bolts/nuts.

OEM cowl fins by Max Mutarn, on Flickr


Nylon bolts before drilling.

Nlyon fin bolts before by Max Mutarn, on Flickr


nylon fin bolts 2 by Max Mutarn, on Flickr



Nylon fin bolts after 1 by Max Mutarn, on Flickr






Carbon fins and nylon bolts.


DW carbon fins and nylon bolts by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

Made one other part in carbon, the starter motor cover plate. The shape of the cover is one that a vacuum unit would have made without a problem. Making it by hand got pretty ugly and took a few tries to get it right. The curves just didn't want to release from the OEM metal cover no matter how much release agent I used.

 

[eil]

This is one of the most interesting threads I've seen on this forum in a long time. Following with interest.

 

[Shin-Ken 1074]

This is one of the most interesting threads I've seen on this forum in a long time. Following with interest.

Hi Eil, thank you.

 

[Shin-Ken 1074]

Rear caliper bracket paint has cured after the modification to adapt the K5 rear brake caliper to the 1981 Suzi swing-arm. Swing arm, caliper and rear wheel will be installed next week.

The stock K5 mount.


OEM K5 caliper bracket by Max Mutarn, on Flickr


K5 mount mod.

DW caliper bracket com1 by Max Mutarn, on Flickr


DW caliper bracket com2 by Max Mutarn, on Flickr


K5 caliper and DW bracket by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

The exhaust system for the DW had steel header flanges fitted when I bought it so they had to go. Didn't want to damage the headers using an angle grinder with a cutting disc so used a hacksaw blade and slowly worked through each flange. No damage done.

Four of these and eight steel bolts, 840 grams total.

Shouldn't need to many guesses as to what will replace these boat anchors.

Steel header flange 1 by Max Mutarn, on Flickr


Steel header flange 2 by Max Mutarn, on Flickr



Steel header flange 3 by Max Mutarn, on Flickr

 

[Rob S.]

Full titanium exhaust, I presume? :applouse:

 

[Pewpew82]

The exhaust system for the DW had steel header flanges fitted when I bought it so they had to go. Didn't want to damage the headers using an angle grinder with a cutting disc so used a hacksaw blade and slowly worked through each flange. No damage done.

Four of these and eight steel bolts, 840 grams total.

Technically, would the original weight be slightly more than the aforementioned 840 grams only since you are not measuring the removed materials from the saw? Maybe closer to 850 grams by my estimation?

Either way, I am fully invested in seeing the final product and thoughts after riding it. You are doing great work.