1981 GSX1100 Katana Based Project

[Shin-Ken 1074]

I wanted something lighter, more compact and a bit "Old School" in looks. Doesn't get more "Old School" than mesh screens. I couldn't find a screen to fit the intake boots in any of the usual auto suppliers I deal with so started to look elsewhere. Tea strainer does a similar job so off to the kitchen department at the local shop and found these. Got a few strange looks as I was measuring the strainers but in the end found a perfect size strainer in fine stainless mesh.


Carb intake 2 by Max Mutarn, on Flickr


Removed the strainer from the frame and used a hot glue gun to marry the screen to the boot.

Carb intake 5 by Max Mutarn, on Flickr


Carb intake 4 by Max Mutarn, on Flickr

Carb intake 6 by Max Mutarn, on Flickr


Exactly what I wanted. Only has to keep out birds, insects and childrens fingers. Not worried about ultra fine dust and engine wear, at my age I will be worn out before the engine is worn out from the occasional bit of dust it may ingest.


Foam v screen. Screen wins!


Foam filter 2 by Max Mutarn, on Flickr

 

[GRich]

Great project so far!

I saw the carbs were mentioned a couple couple ago, and it reminded me of my old GS450S. I replaced the stock carbs for ones from a 1st generation GS500 for pure performance gains, and was really surprised at the weight difference! I didn't have an accurate scale, but the GS450 carbs were easily a couple pounds heavier.

 

[Shin-Ken 1074]

The 1981 34 mm CV carbs are pretty heavy and parts availability and price are becoming an issue and I want to keep this ride for the next 20 years. Will be swapping them for 2004 GSX 750 carbs, lighter and all parts are still available.


1981 34mm CV

34 mm CV by Max Mutarn, on Flickr


2004 GSX 750 36mm CV, even with the throttle cable attached it is almost a kilo lighter.


2004 GSX 750 by Max Mutarn, on Flickr

 

[Blower]

Getting engine lighter:
- Hayabusa gen2 pistons
- EFE cylinder block sleeved with Bandit 1200 liners and bored to 81mm
- Titanium valve spring retainers
- Cylinder head porting
- Regrinded camshafts

After those modifications your engine is not only lighter, but more powerful = your bike feels lighter

 

[Shin-Ken 1074]

Getting engine lighter:
- Hayabusa gen2 pistons
- EFE cylinder block sleeved with Bandit 1200 liners and bored to 81mm
- Titanium valve spring retainers
- Cylinder head porting
- Regrinded camshafts

After those modifications your engine is not only lighter, but more powerful = your bike feels lighter

Very good mods for performance. Excluding the Ti retainers as they are a given to be lighter than OEM retainers. Did you weigh each OEM component before the mods and weigh the new parts to compare the weight difference, or did you weigh the complete engine before and after the mods to confirm the amount of weight reduction?

 

[Blower]

Very good mods for performance. Excluding the Ti retainers as they are a given to be lighter than OEM retainers. Did you weigh each OEM component before the mods and weigh the new parts to compare the weight difference, or did you weigh the complete engine before and after the mods to confirm the amount of weight reduction?

I never weighted cylinder block before and after, but weight difference was noticeable, as was with pistons.
The whole bike (1150 EFE) after all modifications and rebuild was fuel tank half full weighted in MOT slighltly under 200 kg.
RW hp gain was from original 92hp to 142hp.

 

[Shin-Ken 1074]

Shocks arrived today, well packed and with a detailed manual to assist with settings.



Shocks 1 by Max Mutarn, on Flickr


Shocks 2 by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

Each Nitron is 711 grams lighter than the shocks they will replace!

Shocks 3 by Max Mutarn, on Flickr


Shock lower bolts by Max Mutarn, on Flickr


DW shock lower boltsIMG_3346 by Max Mutarn, on Flickr


Shock OEM top nut by Max Mutarn, on Flickr


DW shock top nut by Max Mutarn, on Flickr


Current shocks = 3,994 g
steel lower bolts = 164 g
steel top nut = 24 g

Nitron shocks = 2,572 g
Ti lower bolts = 108 g
Ally top nut = 12 g

End result is:

4,180 grams vs 2,692 grams.

1,488 gram reduction is O.K. with me.

 

[Diirk]

I'm thoroughly excited to see the end result, but at the same time I'm not in a hurry to see it either because I'm enjoying the process
Those Nitron shocks look the mutt's nuts btw.

 

[Shin-Ken 1074]

I'm thoroughly excited to see the end result, but at the same time I'm not in a hurry to see it either because I'm enjoying the process
Those Nitron shocks look the mutt's nuts btw.

Yeah, I am looking forward to how the Nitron shocks perform on the DW. The shocks are made in the U.K. and the DW 180 specs were provided so the shocks could be built with valves and springs to suit the DW. Ordered, built, shipped and delivered in two weeks to the other side of the world, that is great customer support in my book.

 

[Shin-Ken 1074]

Plan A was to use OEM front calipers however, that has changed and now later model Suzi twin-pot calipers that offer better performance are lighter than OEM and all the parts are available so these can be maintained for many years to come.

Plan B is to use 2004 GSX 750 front calipers, some fine tuning is needed to get the calipers lining up true with the rotors and mounting brackets will need to be made because the 2004 caliper mounts are a different pitch to OEM SZ calipers.

The rightside outer wheel spacer needed a bit of a trim, file and wet sanding has it to the correct size now. Not a big problem considering the calipers are now being changed from the original plan and the Slabbie front wheel was turned down on a manual lathe to fit the Kat forks. It is a miracle the front spacers were only out by 1.75 mm after the change in plan.

2004 caliper, twin piston, larger pads and lighter than OEM.


2004 GSX 750 caliper by Max Mutarn, on Flickr


spacer 1 by Max Mutarn, on Flickr


Spacer 2 by Max Mutarn, on Flickr



Spacer 3 by Max Mutarn, on Flickr




Spacer 5 by Max Mutarn, on Flickr



Spacer 6 by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

New carb boots have arrived so carbs on today as well as a few other parts.

Carb boots by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

As a percentage of weight saved replacing the OEM auto cam chain tension unit with a manual unit is a winner.

OEM cam chain tensioner by Max Mutarn, on Flickr


DW cam chain tension manual by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

Cam chain with manual tension unit fitted, before setting chain tension.

Cam Chain 1 by Max Mutarn, on Flickr


Tension set with manual cam chain unit.


Cam chain 2 by Max Mutarn, on Flickr


Cam chain run-out checked, all good.

Cam chain 3 by Max Mutarn, on Flickr

Manual cam tension unit installed.


Cam chain 4 by Max Mutarn, on Flickr




Running tally = 153,275 grams.

 

[Shin-Ken 1074]

Aluminium battery cradle and Ti bolts ready to go.

Ally cradle 1 by Max Mutarn, on Flickr

Ally cradle 2 by Max Mutarn, on Flickr




Running tally = 153,534 grams.

 

[Shin-Ken 1074]

OEM oil pressure sensor and Ti bolts.


Oil press sensor 1 by Max Mutarn, on Flickr


Oil press sensor 2 by Max Mutarn, on Flickr


Running tally = 153,649 grams.

 

[Shin-Ken 1074]

Before installing the carbs they need a manual choke to be fitted. There is some damage to the carb fittings so I will have to work with what I have. Found an old manual door lock knob off a vehicle from who knows what in the box of things you never throw away. I think I can get this to work.

door lock by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

First thing is to file away some material to allow the lock rod to fit the carb mount, the one that isn't broken.

choke 1 by Max Mutarn, on Flickr


choke 2 by Max Mutarn, on Flickr


choke 3 by Max Mutarn, on Flickr


The choke rod fits, now to work out how to secure it to the choke bar where the original choke cable would have been attached.


choke 4 by Max Mutarn, on Flickr

 

[Shin-Ken 1074]

Shaped the end of the rod into an eye and then filed it flat to fit inside the original choke cable holder. M4 bolt and locknut to secure the rod in the cable holder. New choke works smoothly with full range of movement for the choke rail. I installed the manual choke on the left side of the carbs so the choke can be used with the left hand while the starter button and throttle are operated as usual.

Choke 6 by Max Mutarn, on Flickr


Choke 7 by Max Mutarn, on Flickr


Choke 8 by Max Mutarn, on Flickr


Choke 9 by Max Mutarn, on Flickr


That is all for today, its cold beer time now.

 

[Rich82GS750TZ]

That’s some slick fabricobbling, Max.