1981 GSX1100 Katana Based Project

[Shin-Ken 1074]

Aluminium rear indicator brackets in primer.

rear indicator brackets 5 by Max Mutarn, on Flickr


Head light surround Satin Black to match the cowl head light Satin Black area.

head light surround satin by Max Mutarn, on Flickr

[Shin-Ken 1074]

Swapped the rear reflector for a lighter (and brighter) version.

RR1 by Max Mutarn, on Flickr


RR2 by Max Mutarn, on Flickr


RR3 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Swapping the OEM steel rear indicator brackets for aluminium brackets.


rear indicator bracket 1 by Max Mutarn, on Flickr


rear indicator bracket 2 by Max Mutarn, on Flickr


rear indicator bracket 3 by Max Mutarn, on Flickr


rear indicator bracket 4 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Headlight surround today, usual suspect - aluminium.

surround 1 by Max Mutarn, on Flickr


surround2 by Max Mutarn, on Flickr


Surround in primer.
surround5 by Max Mutarn, on Flickr

[Shin-Ken 1074]

I've just discovered an area for additional weight savings!

No way, I am not giving up ribs and beer over Christmas!

[Rob S.]

I am 94 KG so a bit less than 500 lb, before Christmas and New Years anyway!

I've just discovered an area for additional weight savings!

[Shin-Ken 1074]

Remember that a box-stock 1983 11ES was the first bike that Cycle World got into the tens (just barely - 10.99). The difference was the 'bikini' fairing.

With a larger engine, and much less weight, your Kat should easily do mid tens. Unless, of course, you're a 500 pound fat slob or measure your self in kilograms, whatever those are.

Kilograms - whatever those are.

I am 94 KG so a bit less than 500 lb, before Christmas and New Years anyway!

[Rob S.]

With the focus on shedding weight above all else unfortunately performance had to take a backseat on this build. However, with an improved power to weight ratio there will be some gain in performance. I think it would be a struggle for high nines or even 10's and 11's but whatever it could do would still be fun?

Remember that a box-stock 1983 11ES was the first bike that Cycle World got into the tens (just barely - 10.99). The difference was the 'bikini' fairing.

With a larger engine, and much less weight, your Kat should easily do mid tens. Unless, of course, you're a 500 pound fat slob or measure your self in kilograms, whatever those are.

[Shin-Ken 1074]

Trimmed the outer edge and hogged out the bracket to match the cowl bracket hole. Bonus - 1 gram lighter. 1 gram doesn't sound like much but it is the percentage removed from each part that adds up to the weight reduction overall. In this case 1 gram is just under an 8% reduction in weight.

DWhorn18 by Max Mutarn, on Flickr



Bracket 1 by Max Mutarn, on Flickr


bracket2 by Max Mutarn, on Flickr

[Shin-Ken 1074]

DW horn a5 by Max Mutarn, on Flickr


DW horn a1 by Max Mutarn, on Flickr


DW horn a3 by Max Mutarn, on Flickr


DW horn a4 by Max Mutarn, on Flickr



Bracket is now ready for paint and those bolts in the pic are not the bolts that will be used for the finished bracket.

My estimate of 246 grams for the new horn and bracket were a bit off.

I just noticed in the 2nd last pic the outer edge of the bracket can be trimmed to match the cowl bracket.

[Shin-Ken 1074]

DWhorn a9 by Max Mutarn, on Flickr


DWhorn a6 by Max Mutarn, on Flickr


DWhorn a8 by Max Mutarn, on Flickr


DWhorn a7 by Max Mutarn, on Flickr


DWhorn15 by Max Mutarn, on Flickr


DWhorn11 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Had a chance to sort out the lighter horn bracket today. I have used thin ally for the bracket and with 253 grams hanging on the bracket I decided to use a triangular bracket to offer better support, a few grams heavier but eliminates the chance of the horn moving if it was attached with a single bolt.



DWhorn12 by Max Mutarn, on Flickr



DWhorn13 by Max Mutarn, on Flickr


DWhorn14 by Max Mutarn, on Flickr


DWhorna10 by Max Mutarn, on Flickr

[Shin-Ken 1074]

What do we estimate this Kat will do in the quarter mile? I'll venture high nines with a good, light rider. Maybe 130 mph at the end.

With the focus on shedding weight above all else unfortunately performance had to take a backseat on this build. However, with an improved power to weight ratio there will be some gain in performance. I think it would be a struggle for high nines or even 10's and 11's but whatever it could do would still be fun?

[Shin-Ken 1074]

On the leitmotiv of the thread, I seem that, by halving the clacsons of post # 370 in two, you could see a weight saving of 27gr out of nothing (single clacson = 282gr twin = 509/2 = 254gr)

I'm starting to dig this bike;

Yes, the twin horn weight when halved would be like you say = 254 g and lighter than the single horn. Turns out each horn is the same weight and it is the brackets that account for the difference in weight, the single bracket is heavier than it should be because of where it was designed to be mounted. With an alternative horn position there is no reason why the new bracket can not be smaller and lighter. That's the plan for now.

OEM twin horn by Max Mutarn, on Flickr


The solution is to make a smaller bracket in aluminium to replace the steel OEM single bracket. My estimate is the single horn with an ally bracket should come in at around 246 grams.


OEM single horn bracket by Max Mutarn, on Flickr

[Rob S.]

What do we estimate this Kat will do in the quarter mile? I'll venture high nines with a good, light rider. Maybe 130 mph at the end.