1981 GSX1100 Katana Based Project

[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.

:encouragement:

 

[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.

 

[steve murdoch]

This is great, even the bolts look cool!

 

[Shin-Ken 1074]

Hi Steve, the Ti bolts look even better now they are on the Kat!

steel swapped for Ti by Max Mutarn, on Flickr

Replaced these steel bolts with Ti bolts and shaved 189 g from the tally.

Running tally = 184,496 grams.

 

[Shin-Ken 1074]

Worn OEM rubber grip swapped for the new foam grip, 50 grams lighter.

foam grip twin by Max Mutarn, on Flickr

Running tally = 184,446 grams.

 

[Shin-Ken 1074]

Have a few things to sort out before the big fella in the red suit turns up on Monday to share a beer and a few prawns so not much will be getting done on the build for the next few days.

Wishing everyone a Merry Christmas and a Happy New Year, keep the shiney side up and watch this space.

Cheers.

 

[Rob S.]

184,446 grams = 406.6 lbs...that's light! That's dry weight, right?

That's more than 150 pounds you've shaved off. That's amazing! :lemo:

 

[Shin-Ken 1074]

As of today the tally is 184,446 grams however, there are a couple of parts that could be modified and shave a few more grams off the current tally, and I mean only a few grams nothing more.

If the Suzi factory manual is accurate, it quotes the dry weight for a 1981 1100 Kat at 232 kg. So using the factory quoted dry weight of 232 kg as the baseline the build is at 184,446 grams which means 47.554 kg has been removed from a stock Kat.

The goal for the build was to shave 50 kg off because 50 kg was a nice round number and gave me a target to aim for and was based on my estimate of what I thought I could do to reduce the OEM weight. At 47.554 kg it has fallen short of the goal however, there are still a few things that could be done like a smaller flywheel and stator and a smaller starter motor. Parts, engineering and cost are the barriers to do these mods right now so they are not on the must do list at this stage.

The low hanging fruit as the Kat stands now are indicators, instruments and mirrors. By swapping these factory parts for lighter aftermarket parts there is 2kg to be saved however, one of the criteria for the build was to have the finished build look like a Kat and to do that factory mirrors, instruments and indicators are a must have so for now they stay.

I would like to think there will be some adjustments here and there so I am not signing off on the build at this stage. The engine has been run but it hasn't turned a wheel yet so there is still plenty to do, not so much with weight but other things to sort out before it is a road going build.


I need to go through the build tally to ensure all is above board with the numbers however, as of today the reduced weight of 47.554 kg = 104.8 lb.

Cheers.

 

[Shin-Ken 1074]

184,446 grams = 406.6 lbs...that's light! That's dry weight, right?

That's more than 150 pounds you've shaved off. That's amazing! :lemo:

Hi Rob, to have 150 pounds off would be fantastic however, the converter I used for kg to lb gave a figure of 104.8 lb.

 

[Shin-Ken 1074]

Hi Folks, after having the Christmas and New Year holiday it is time to get back on to the build. Some wiring to sort out as well as finding out why the rear tail light doesn't work. Carbs still need some attention and perhaps re-jetting, will get on to that once the Kat is up and running after the wiring is finished. The identity of the front calipers has yet to be confirmed however, pretty sure they are 2004 750 F calipers. Have ordered one 750 F caliper re-build kit from Suzuki to see if they are in fact 750 F calipers, also included a rear master cylinder kit in the order.

Will strip and clean the calipers and check the condition of the bore in each this week sometime.

 

[Shin-Ken 1074]

Carb cleaning time, not a complete strip down, that was done a few thousand km ago so it is just cleaning bowls, checking floats/pins and jets for varnish. Bought these screwdrivers about 10 years ago just for carb use only, they live in the study to keep them from being used as general purpose drivers, levers and scrapers.

carbs1 by Max Mutarn, on Flickr


Drivers by Max Mutarn, on Flickr

 

[Lorenzo]

Bought these screwdrivers about 10 years ago just for carb use only, they live in the study to keep them from being used as general purpose drivers, levers and scrapers.

J I S man...

 

[Rob S.]

Hi Rob, to have 150 pounds off would be fantastic however, the converter I used for kg to lb gave a figure of 104.8 lb.

I guess I was going off my 11EZ weight of 567 lbs.

J I S - one of those things I was ignorant of when I got my first street bike at 18 and HAD to ride 100 miles every day.

 

[Shin-Ken 1074]

J I S man...

Careful how you spell that one Lorenzo!