1981 GSX1100 Katana Based Project

[Shin-Ken 1074]

Swapped the throttle tube and checked the throttle stop/idle gap, about 8mm, hhmmm the new cable is still short and putting tension on the carbs spindle. With no adjustment left for the throttle cable I decided to sacrifice a damaged throttle tube by cutting the stop shorter to allow more cable through the system.

tube 6 by Max Mutarn, on Flickr


Lowered the gap about 3 mm but still to high and idling at 1600 revs. I wouldn't trust the cut throttle tube even if it did lower the revs to the correct idle. So for now the two options to fix the problem are:

1) a longer throttle cable,

2) swap or modify the carb throttle cable bracket.

Will check the parts bin to see if there is an 1135 EF throttle cable lurking about and try that first.

[Shin-Ken 1074]

No joy finding an 1135 EF cable in the spares bin. There is little to no space available to modify the carb throttle bracket which is my preferred option as then stock throttle cables can be used. Will have to spend some time working this one out.

Where the throttle should be.

stop 1 by Max Mutarn, on Flickr

To gain a few mm positioned both lock nuts below the bracket and with cable at full adjustment top and bottom the cable is in tension and holding up the throttle stop.

stop 3 by Max Mutarn, on Flickr

stop 2 by Max Mutarn, on Flickr

[Lorenzo]

On friday evenings I've made my ow throttle cables;
I even went as far as (no big deal really) melting the small lead ball which goes inside the slide (Mikuni carbs), and the barrel shaped one -for the throttle tube.
One Sunday morning, a cable end and a length of 12mm cable saved my trip.

That Kats lineup is awe inspiring; those machines carry a menace or a promise...

[Shin-Ken 1074]

On friday evenings I've made my ow throttle cables;
I even went as far as (no big deal really) melting the small lead ball which goes inside the slide (Mikuni carbs), and the barrel shaped one -for the throttle tube.
One Sunday morning, a cable end and a length of 12mm cable saved my trip.

Great work Lorenzo, and good to hear your trip was saved.

[Shin-Ken 1074]

Yayyyyy, found the EF throttle cable, too short by a mile so that eliminates one option.


Effy cable by Max Mutarn, on Flickr

[Shin-Ken 1074]

While ratting through the EF parts box I found this. I don't know if it is a genuine EF horn but that doesn't matter, what matters are the numbers on the scale.

horn b 2 by Max Mutarn, on Flickr

The SZ horn is getting the flick and this little gem is getting the gig.

horn b 3 by Max Mutarn, on Flickr


horn b 5 by Max Mutarn, on Flickr

horn b 6 by Max Mutarn, on Flickr


A very nice surprise and a 119 gram reduction from the running tally.

Running tally = 184,585 grams.

[Rob S.]

The first time I ever rode a motorized 2-wheel vehicle was my 12th summer, and I was finally granted a turn on some kid's mini bike. A generic little vehicle with Briggs & Stratton 3 hp pull rope to start engine that was ubiquitous in those days. Hooray! But...

The twist grip throttle was broken, and it was ridden with a hand on the carburetor. A bummer, but it was still enough to hook me for the next 55 years.

[Shin-Ken 1074]

The first time I ever rode a motorized 2-wheel vehicle was my 12th summer, and I was finally granted a turn on some kid's mini bike. A generic little vehicle with Briggs & Stratton 3 hp pull rope to start engine that was ubiquitous in those days. Hooray! But...

The twist grip throttle was broken, and it was ridden with a hand on the carburetor. A bummer, but it was still enough to hook me for the next 55 years.

Same here, I was very young and my first two wheel ride with an engine was on a machine owned by a friend, Phillip. Still remember the fun we all had racing it around at a good 15 miles an hour, oh the speed, but it was enough to get me interested in riding bikes and that has stayed to this very day.

Can't remember the brand of the bike but it had the Briggs/Stratton red engine in red frame with a flat white seat and semi ape hanger bars that made us look super cool and yes, the rope pull start, not so cool. We were lucky, the hand throttle worked.

[Shin-Ken 1074]

Update regarding the throttle cables. As much as I wanted to use OEM Kat switchblocks for the build I don't want to butcher expensive OEM vintage switchblocks that I can use on my other Kats if needed. Spoke with some mates who have installed 750F carbs on their Kats and they advise the best option is to find a genuine Suzi twin cable switchblock and keep it simple. New cables are available from Suzuki and at AUD $34.70 each so they are not much more than the aftermarket cables for sale around the place.

Have found a used swithblock and have been told it will arrive by 27 Dec at the latest. I am hoping that is the end of the cable issue, will know for sure soon enough? Twin throttle cables, can't wait to add extra weight.

[Shin-Ken 1074]

Fuse cover was showing 40 plus years of wear and tear so gave it a tidy up with a clean and coat of paint.

Fuse cover by Max Mutarn, on Flickr

[Shin-Ken 1074]

The replacement horn in primer.

horn b10 by Max Mutarn, on Flickr

[Shin-Ken 1074]

The replacement and much lighter model horn now installed and operational.

Horn b 13 by Max Mutarn, on Flickr


Horn b12 by Max Mutarn, on Flickr

[Shin-Ken 1074]

During the mock-up, testing and fitting stage the front calipers were bolted on using steel allen bolts however, now that the caliper installation has been sorted the steel allen bolts can be replaced. There were a few other places that had steel bolts being used so while ordering the caliper bolts I added the extra few tapered Ti bolts as well to shave off a few more grams.


After the bolts have been swapped I'll weigh the steel bolts to compare the difference between steel and Ti.

Ti bolts 1 by Max Mutarn, on Flickr


Ti bolts 2 by Max Mutarn, on Flickr

[Shin-Ken 1074]

The twin throttle and cables have arrived, 500 grams!


Twin throttle 1 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Have swapped the single throttle and cable for the twin set-up. Single throttle = 400g. Twin throttle = 500g.


Single OEM throttle by Max Mutarn, on Flickr

The twin throttle is fitted with a rubbber grip so that needs to be swapped for the light weight foam grip so a few more grams to be saved after the grips are swapped. For now the tally will be with the rubber grip.

Running tally = 184,685 grams.