1981 GSX1100 Katana Based Project

[Shin-Ken 1074]

The 02 sensor reading shows that at WOT things could be improved a fraction by going up a size in main jets so today was swapping main jets day. Removing and installing the carbs is so quick and easy on this build because it isn't fitted with an airbox, with the tank off and throttle cable released, it is just the four inlet boot clamps to release and slid the carbs out. Larger jets are now installed and ready for testing with the 02 sensor tomorrow.

I reshaped a screwdriver to match the Mikuni jet slot, doing this eliminates damage to the jet shoulders that a standard screwdriver causes due to the screwdriver taper putting pressure on the jet top edge and none on the lower section of the jet slot.
Carb 20 by Max Mutarn, on Flickr


Carb 30 by Max Mutarn, on Flickr


Carb 31 by Max Mutarn, on Flickr

[Shin-Ken 1074]

The test ride with the new jets went pretty well and the 02 readings have the carbs almost in the sweet spot, almost. WOT is still the problem child however, another jet size up should fix the issue. I am out of jets now so the next size will be ordered today and should arrive by next Monday all going well.

[Rob S.]

Dude (that's how we talk in the north), I might have a serious issue with your "DW" project for the first time. It all depends; it might just be a translation error (my Austrian has never been fluent).

You mentioned that "WOT" would never be used when riding this bike. Does WOT stand for 'wide open throttle' on your end of the planet? If so, I can no longer be associated with this project. Let me know, so I can go back and delete all of my posts on this thread. I wouldn't want it to appear that I approve of such a fanatical riding philosophy.

Of course, you may wish to retract your statement. Maybe you were having a bad day. It happens. Perhaps you were at the beach and got some sand in your va jay jay.

Maybe I'm wrong. Maybe "Wide Open Throttle" doesn't even mean what I think it does. I thought it meant twisting the throttle as far as possible on a motorcycle, and 'flooring' it on a car. Pedal to the metal.

Maybe I'm wrong, and the terminology has changed. If so, I apologize. But let's clear this up ASAP. Okay?

[Shin-Ken 1074]

Yep, WOT means the same thing here. It'll be a pity to see you go however, I understand you have to standby your values. Hope you don't pick up a repetitive strain injury tapping "Delete".

[Shin-Ken 1074]

The new main jets arrived today, with rain forecast for the next week here it'll be awhile before they see any fuel.

Jets 160 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Hoping the weather is fine at some stage over the weekend so I can take the DW on test ride with the latest main jets that I installed this week. I noticed an oil weep around the oil sensor plate, checked the plate while the carbs were removed and sure enough the oil pressure o-ring and oil sensor plate o-ring were past their prime. Bought new o-rings, sealing washers and bolts for the plate. Installed the new seals so that should take care of the oil weep issue.

Latest main jets installed.
Main jet by Max Mutarn, on Flickr


Oil sensor plate
Oil press sensor 2 by Max Mutarn, on Flickr


Oil sensor plate by Max Mutarn, on Flickr

Old vs new oil pressure sensor o-ring.
Oil pressure sensor o-ring by Max Mutarn, on Flickr


Old vs new oil sensor plate o-ring.
Oil sensor plate o-rings by Max Mutarn, on Flickr

Latest main jets installed and oil sensor o-rings, bolts and seals replaced, now just waiting for a fine day.

[Big Block]

One of these days I'm going to try a jet change with the carbs still installed on the engine. It'll take patience but I think I can do it. The stock airbox/airfilter on these bikes is a hassle for sure.

[Shin-Ken 1074]

One of these days I'm going to try a jet change with the carbs still installed on the engine. It'll take patience but I think I can do it. The stock airbox/airfilter on these bikes is a hassle for sure.

Yeah, totally agree with you on that one, carbs off, carbs on with the stock airbox is no fun at all! Changing the main jets with the carbs in place is doable and as you say patience is the key when doing it that way. A short shank angled blade screwdriver made to length would be helpful. Another thing that would be helpful in future, is once the fuel bowls are removed, swap the fuel bowl screws for allen head bolts, much easier to remove the bowls and re-fit with an allen key in the restricted space rather than with a stumpy screwdriver.

[Shin-Ken 1074]

At last, a fine sunny day! Took the DW out for a test ride with the latest main jets and the 02 sensor numbers are looking pretty good.

From idle at 12.7 through the 5 throttle settings to WOT at 13.2, not perfect but pretty close. Speed readings for 40 kph, 60 kph, 80 kph and 100kph are all 12.4.

Throttle is crisp with instant power in all gears and no lag at all. Made some minor suspension adjustments and set the front tyre pressure at 34 PSI and the rear at 40 PSI. Steering is light and very responsive with minimal input needed to turn or change the riding line when deep into the corner at any speed. Suspension front and rear is smooth and handles bumps and uneven surfaces so well there is no need to try and dodge the road bumps. So carbs and suspension are now sorted. Next job is to install the oil cooler.

[Lorenzo]

Dunno, Captain America had no front brake; that's what I call some serious weight savings...

[GSX1100 dreamn]

What are you doing with these two sensors.

sensor.jpg

Cheers Andrew.

[Shin-Ken 1074]

Hi Andrew, your eagle eye has spotted the two oil temp sensors. The OEM sensor on the block is not connected to a read out (1135 clocks not being used) so I have installed a temporary (the red sensor in the pic) oil temp sensor and digital readout to monitor oil temps during the bedding in period. The extra weight of the red Yoshi sensor will be removed once everything is sorted out.

Cheers.

[GSX1100 dreamn]

Progress 1 or 2.

I found the inlet cam plug to give the most accurate engine temp in a sort of way. The oil temperature readings and and my 1250 CT readings were like for like at this position.

[Shin-Ken 1074]

Progress 1, using the port closest to the oil pump for the temp readings.

oil temp 1 by Max Mutarn, on Flickr

[Shin-Ken 1074]

With more ride time on the DW I am now getting a better feel for how I want to set things up, like last week with the suspension and tyre pressure. Next on the list is how I want to position the bars. The clip-ons are an aftermarket two part system with the bar using a spline to engage the clamp with a single bolt that not only clamps the bar to the fork leg it is also allows the bar position to be adjusted by repositioning the bar on the spline, simple, effective and most importantly, light!

The bars have been rotated up and forward and so far so good. Bars position adjustment is fast and easy and can be done on the fly as long as I remember to pack the 12 point socket in the tool roll.

The 12 point bolt in the pic locks the splines of the bar and clamp together as well as clamping the bar to the fork.
Aftermarket moly clip-on by Max Mutarn, on Flickr