1981 GSX1100 Katana Based Project

[Shin-Ken 1074]

The adjustable bars with their original steel allen bolt and showing the spline adjustment before painting them and swapping the allen bolt for a titanium bolt.

Bars 1 by Max Mutarn, on Flickr


Bars 2 by Max Mutarn, on Flickr

[Shin-Ken 1074]

How the adjustable clip-ons look in the raised and slightly forward position, a bit flat bar looking but nothing wrong about that.

Clip on 1 by Max Mutarn, on Flickr

[Shin-Ken 1074]

There I was happy as a clam after dialing in the carbs and getting the Kat running oh so good and then, I get asked, "How would you like to fit a set of Mikuni 38mm flat slides to the DW?" I have ridden Kats with 38 mm flat-slides and WOW, they are a weapon!

With the time and effort invested to set up the 36mm CV carbs I was reluctant to think about starting over again setting up the flat-slides however, they are a good mod for the 1135 engine so Iam leaning towards going with the flat-slides. They weigh more than the 36 mm CV's but there are some mods that will reduce the weight by a few grams. Hhhhmmmm, ah why not, I think I'll give the flat-slides a go.


Mikuni 38 mm flat-slides
38 mm Flatslides by Max Mutarn, on Flickr

[steve murdoch]

Another chapter in this epic journey. Excellent!

https://www.orientexpress.com/Images/document/large/Mikuni-rs-manual.pdf

[Shin-Ken 1074]

Another chapter in this epic journey. Excellent!
https://www.orientexpress.com/Images...-rs-manual.pdf

Hi Steve, it will be awhile before the RS flat slides are installed, need to sort out super light weight spun aluminium velocity stacks, twin cables and switchblock throttle before the carbs can be bolted on. I am hoping this chapter will be shorter than it was setting up the 36mm CV's, now that was epic working through six jet sizes until hitting the sweet spot.

Thanks for the link to the RS specs and application chart, that will be helpful as the carbs I am buying are just the carbs, no chart included.

For now the oil cooler is still waiting to be installed so I am trying to get that finished later this week after I have finished replacing a radiator in a home vehicle.

[Shin-Ken 1074]

Swapping the 36mm CV carbs for 38 mm flat-slide carbs will help with performance but they will also add a few extra grams to the build so time to start looking at swapping or modifying parts to off-set the weight gain with the 38 mm flat-slides.

The first part that will be swapped is one that I look at everytime Iam on the DW, the front master res. Found a Brembo res that is lighter, uses a smaller bracket and much smaller bolt, should save around 110 grams not including the brake fluid. The original res was for the large single piston calipers that have been swapped for modern small diameter twin piston calipers so there is no need to lug around all that extra brake fluid. This is one time when small is better.

Front brake 1 by Max Mutarn, on Flickr


Front Brake 2 by Max Mutarn, on Flickr


Front brake 3 by Max Mutarn, on Flickr

[Shin-Ken 1074]

The engine needed a replacement breather vent catch can fitted and it had to be light. I found a small Denso oil cooler from a petrol powered garden rotary hoe that looked like it would do the job. The catch can is installed behind the battery and this location helps to keep the build looking a bit "stock" rather than a modified build with a catch-can installed in place of the front sprocket cover as well as looking tidy. The plumbing and catch can (empty) weigh 461 grams in total so it is pretty light. The bracket is made from flat aluminium with polymer spacers to keep the weight down to a reasonable level.

Running tally = 182,056 grams.


Oil cooler converted to a catch-can.
Catch can 1 by Max Mutarn, on Flickr


Catch can 2 by Max Mutarn, on Flickr


Catch can c by Max Mutarn, on Flickr


Catch can d by Max Mutarn, on Flickr

[Blower]

Hi Steve, it will be awhile before the RS flat slides are installed, need to sort out super light weight spun aluminium velocity stacks, twin cables and switchblock throttle before the carbs can be bolted on. I am hoping this chapter will be shorter than it was setting up the 36mm CV's, now that was epic working through six jet sizes until hitting the sweet spot.

Thanks for the link to the RS specs and application chart, that will be helpful as the carbs I am buying are just the carbs, no chart included.

For now the oil cooler is still waiting to be installed so I am trying to get that finished later this week after I have finished replacing a radiator in a home vehicle.

I'm looking forward to seeing what settings the carburetors will have. I was trying to get 38RS Mikuni set up for my 1296cc GSX. I couldn't get the mixture lean enough with the y-6 needle jet and the y-3 needle. Either the needle tubes are worn, or they are too rich for my setup.

[Shin-Ken 1074]

I'm looking forward to seeing what settings the carburetors will have. I was trying to get 38RS Mikuni set up for my 1296cc GSX. I couldn't get the mixture lean enough with the y-6 needle jet and the y-3 needle. Either the needle tubes are worn, or they are too rich for my setup.

When the time comes to set up the 38 mm Flat-Slides I'll post the details here, I want to get in some riding before swapping the carbs so it wont happen too soon, but it will happen.

[Shin-Ken 1074]

While I am sorting out the oil cooler installation now is the time to make the cooler protector screen. Some of the out of the way roads I ride on are pretty rough and on a couple of rides stones have been kicked up by on-coming vehicles and damaged the oil cooler on one of the other bikes that didn't have a screen fitted. Rounding up a rescue trailer for a long trip home is no fun when you are in the sticks with no phone coverage! An aftermarket screen isn't available for the cooler Iam going to use so its time to make one.

Oil cooler 32 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Before starting on the cooler screen I need to revisit the oil cooler lower bracket design, I have come up with a better bracket design that will also secure the protector screen if all goes to plan. This is the start of the MK II aluminium lower bracket.

Oil cooler 33 by Max Mutarn, on Flickr


Oil cooler 34 by Max Mutarn, on Flickr


Oil cooler 35 by Max Mutarn, on Flickr

[Shin-Ken 1074]

MK II lower oil cooler bracket.


Oil cooler 36 by Max Mutarn, on Flickr


Cooler and bracket surface area scuffed up and ready for the automotive structural adhesive, no bolts or rivets needed when using this product!
Oil cooler 37 by Max Mutarn, on Flickr

The adhesive is designed for automotive use and I have used this stuff for years on vehicles and bikes, flush tidy finish and lighter than bolts, so far so good!
Oil cooler 38 by Max Mutarn, on Flickr

P.S. No, I don't sell the stuff or work for the company, I just like to use quality products that have proven to be reliable when I have used them.

[Shin-Ken 1074]

The MK II lower cooler bracket has the cooler in its new position that will allow enough space to fit the protector screen. The cooler is in position but not with the correct bolts or spacers. Bolts and spacers will be fitted when the screen is installed.

. Oil cooler 39 by Max Mutarn, on Flickr


Oil cooler 40 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Now that the oil cooler is in place I can work out the details for the cooler screen and cut the ally for the screen frame to size. Have just dropped off the screen frame parts to the ally welder today and hopefully it will be done by this Friday.

Oil cooler 41 by Max Mutarn, on Flickr

[Shin-Ken 1074]

While the oil cooler rock screen is away being welded it is a good time to make the spacers for the cooler and screen. The plan is to use 2 x 10mm spacers between the frame and oil cooler for the top mount to match the 10mm captive nuts welded to the frame that will be the oil cooler lower mounts. Oil cooler on top of 10mm spacers, then 4 x 27mm spacers to allow a gap between the oil cooler fins and the screen. Allen head bolts will go through the spacers and into the captive nuts on the frame.

Cut the spacers from aluminium tube and then used wet/dry to tidy up the cut ends and make then all the same length. The 10mm spacers are to small to fit the tube cutter I have so it is saw time.

Oil cooler 42 by Max Mutarn, on Flickr


Oil cooler 43 by Max Mutarn, on Flickr


Oil cooler 44 by Max Mutarn, on Flickr