1981 GSX1100 Katana Based Project

[Lorenzo]

Very inpressive indeed; given the fact that curb weight varyies from manufacturer to manufacturer, some rate it with a full tank, others with half or 10lt. dry weight comparison might been even more dramatic...

[Rob S.]

From 573 lbs to 454 lbs is VERY impressive. Now for the $64 question: How much do YOU weigh?

Your Kat is a real "Q" ship, a sleeper. Any plans to visit a drag strip? Depending on your skills (and weight ), I see no reason she shouldn't break into the nines.

[Shin-Ken 1074]

That weight saving is incredible!
You should be very proud of all your hard work.

Hey if it's going to wheelie all the time maybe you should weigh it with the front wheel in the air.

Thank you Steve, I appreciate your thoughts on the build. Yeah, with the front wheel in the air I wont need those pesky front brakes so they could come off!

[Shin-Ken 1074]

Very inpressive indeed; given the fact that curb weight varyies from manufacturer to manufacturer, some rate it with a full tank, others with half or 10lt. dry weight comparison might been even more dramatic...

Thanks Lorenzo, yeah, the manual doesn't say how much fuel is in the tank when it quotes the curb weight of 260kg. The main thing is I know what it weighs with a full tank and there are not many 1100 cc bikes with a steel frame that weigh 206 kg with 21 litres of fuel. Dry or wet it is still very light and an amazing bike to ride. I think it will be difficult to throw my leg over any other 1100 road machine now that I have ridden this one.

[Shin-Ken 1074]

From 573 lbs to 454 lbs is VERY impressive. Now for the $64 question: How much do YOU weigh?

Your Kat is a real "Q" ship, a sleeper. Any plans to visit a drag strip? Depending on your skills (and weight ), I see no reason she shouldn't break into the nines.

Q Ship, you know your history. This will stay just that, not standing out in the crowd and being like the "Grey Man" although in this case "Grey Kat" is perhaps a better description. So, no drags, just a Kat to ride and enjoy.

[Shin-Ken 1074]

Great job: Impressive results and I think it still looks great.

Thanks Big Block. While out test riding the Kat, a couple of other riders I meet on the day commented on how factory it looks. To clarify, they were not vintage Kat riders who would notice all the mods straight up however, their comment was how it looked to them as a mostly factory machine. One of the criteria for the build was to try and have a stock "look" for the completed project rather than a resto-mod or custom look to it. Considering there are only eight parts on the completed build that are OEM Katana parts I am happy with the result and how it has a factory "look", excluding the titanium pipes.

I'll post a pic of a stock 1100SZ Kat with the DW to compare and see how close it is to a "factory/stock look".

[KiwiAlfa156]

Well done mate! It's always impressive to see what was along-held dream become reality. I'm betting it's even better than you imagined. Great work as always. I had the pleasure of visiting and riding with an old mate though you're neck of the woods (Tamborine/ Beechmont area) in early Feb. I'm sure the DW180 will be an absolute blast in the Brissie hinterlands.

[Shin-Ken 1074]

Well done mate! It's always impressive to see what was along-held dream become reality. I'm betting it's even better than you imagined. Great work as always. I had the pleasure of visiting and riding with an old mate though you're neck of the woods (Tamborine/ Beechmont area) in early Feb. I'm sure the DW180 will be an absolute blast in the Brissie hinterlands.

Thanks Darryl, yeah, it has turned out even better than I thought it would! Everything is soo much better, seating position, clip-on position, comfort - for a Kat, suspension, handling, brakes, engine performance - it is a weapon!

I mentioned it in a previous post, if I had known how these improvements would make riding so much better I would have done this years ago. It is unlikely I'll ever ride the stock Kat again so she will become a Hanger Queen!

Glad to hear you had a good run through Tamborine/Beechmont, some great roads through there when it's dry. The DW180 only has 35 clicks on the clock as of today however, the plan is to get a couple of short rides in over the weekend to check out the engine and get some oil temp readings at highway speeds and stop/start city traffic.

Great to hear from you mate.

Cheers.

[Rob S.]

The DW180 only has 35 clicks on the clock...

I keep forgetting what DW stands for. A couple of days ago I settled on Dry Weight, but that doesn't work.

I just remember that it was obvious.

[Shin-Ken 1074]

Yep, DW = Dry Weight.

[Rob S.]

Yeah, just reread your first post.

[Shin-Ken 1074]

Have double checked the running tally in the build book and there are some parts that I listed twice, the front guard and bolts and headlight frame which has put the dry weight in error, oops. I have checked and corrected the running tally and then cross checked it with the wet weight.

So the build at the end of stage 1 has the following weights confirmed by commercial scales.

Dry weight = 181.603 kg.

Wet weight = 206.00 kg.

Total weight reduction for stage 1 comparing the factory dry weight vs the DW build dry weight = 50.397 kg.

Total weight reduction for stage 1 comparing the factory wet weight vs the DW build wet weight = 54 kg.

How can there be two different numbers in weight saving? I suspect the factory manual figures are not accurate but which one is the question? The DW build figures are correct as the commercial scales used to weigh the DW have been calibrated and are weighing accurately.

So what does it mean now? Best case is the DW is 54 kg lighter and worst case is the DW is 50.397 kg lighter. I have no control over how the factory manual was put together but I did have control over how the DW was put together and I am very happy with the end result no matter what the manual states.

Motorcycle design and materials have advanced a great deal (not always for the better) over the last 43 years since the 1981 GSX1100S Katana was made by Suzuki. However, it is interesting to see how the DW build compares with one Suzuki's latest bikes, the 2024 GSX-S1000. Suzuki Australia currently list the 2024 GSX-S1000 wet weight at 214 kg. Compared to the wet weight of 206 kg for the DW, looking at those numbers I'd have to say the project has been a success.

Four aluminium bolts arrived yesterday, watch this space.

Aluminium allen bolts by Max Mutarn, on Flickr


Dry weight running tally = 181,603 grams.

[Shin-Ken 1074]

Have swapped the rear tank mount titanium bolts for aluminium bolts today, the ally bolts are much lighter.

Ti tank bolts
Tank bolts Ti by Max Mutarn, on Flickr


Ally tank bolts
Tank bolts ally by Max Mutarn, on Flickr

Dry weight running tally = 181,595 grams.


I have found 9 other titanium bolts that could be replaced with aluminium bolts. My supplier is out of stock right now for M6 x 15 ally bolts so it could be a month before the bolts are swapped.

[Shin-Ken 1074]

The test rides to check on things have been going well so far however, one issue has surfaced that I was hoping wouldn't. I installed an engine oil temp gauge to monitor temps during the test rides and the oil is hitting 122.5 C on 29 C days with 80% humidity. To cope with Summer here the engine will need an oil cooler, adding weight is not what I wanted to do but frying an engine is even worse than adding weight so time to start making brackets and lines for the cooler. Looks like this thread still has a bit of life in it.

[steve murdoch]

Were you stuck in traffic or maybe having a lot of fun in the upper rev range?
That seems like a very high engine temperature for just a 29C day. I'm sure you get hotter days than that.
Just wondering if your temp gauge is properly calibrated?