Time for the big boy to come out to play

No this is not some lewd posting!!!
When you have a number of bikes and projects things tend to get done in cycles. Some time ago I started a cosmetic resto to the big Z, repainted the Z from a horrible brown/red colour back to an original ebony. Got the seat recovered, new exhausts and stuff from the guys in Finland etc. but never finished it off before I started something else. So the main challenge is tackling the old chestnut (or as referred to elsewhere the three dragons). the carburettors. I've been working through all the posts and reckon I've got a good chance of getting it sorted and particularly stopping the current habit of filling the airbox with fuel (better than the crankcase through). It also runs rich and backfires.
So off with the carbs a good clean it will be, then a balance and tune. I'll be following some of the other carb postings with interest in the meantime.

Sounds like you're investing some hefty cash in the beastie, so should look great when it's out !

Re the carbs, when you follow the guides and advice on here it's actually not that bad, the key as ever is just to assume nothing and check every single little flippin' orifice / jet / gallery etc.

I'm just finishing mine off, and by way of an example of unexpected things;

1)Float bowls / general internal dirt levels surprisingly low, but..

2) soaked carbs in diesel for 3 weeks (not necessary but just left them due to other things going on)
DONT soak them in anything chemically agressive!

3)Ultrasonic'd for 90mins after diesel, in water-based carb cleaning solution.

4)After all that;
4 of 6 main jets still blocked solid, needed jet reaming tools to clear.
All emulsion tubes had almost all side drillings still blocked solid, again hand tools to clear.

In terms of reassembly, I always think it's also a good practice to clean-as-you-go, in other words solvent / air-blast each part as you reassemble, that way the risk of any new / recent dust / dirt being introduced is minimised (particularly with your float valves leaking as you describe, on of mine was the same, dripping out like a leaky tap!

5)Remember all cross-headed screws are JIS format and NOT Philips or Pozi etc.
The JIS is a sharper / straighter corner profile on the inner cross part, which means if you use a Philips it rounds and lifts out.
DEFO buy JIS screwdrivers, only 2 sizes needed.
On mine I was able to remove all screws this way by hand, even the big beasties holding the carbs to the crossbar (after chewing one up with a Philips... even though I had the JIS ones to hand.. duuh!)
Scotch also uses a great technique of a screwdriver bit in a pillar-drill chuck, turned by hand with a bar in the chuck locking holes, so you maintain pefect concentricity and can apply downward pressure at the same time, neat!

5)Be meticulous about the two rubber diaphrams in each carb, they're not too expensive and worth swapping if in doubt, to avoid another strip-down later.

6)6 x idle screw o-rings best to change (due to hardness not giving anti-rattle grip anymore) or use Scotchs' trick of replacing with a cut section of small bore silicon tube, great for a snug turnable fit.

Enjoy the Rubik carb puzzle..


Richard.

RChaloner - An intelligent write that is quite revealing. I appreciate and respect your honesty regarding your unsuccessful cleaning results. I think that there are a lot of owners who are too embarrassed to openly acknowledge some failures. So Good on You !
soaked carbs in diesel for 3 weeks
Ultrasonic'd for 90mins
This was the "revealing" part ! It's been noted in the past that Ultra-Sonic Cleaning has it's limitations when dealing with small passages. Never used this method but it's my understanding small passages prevent the sonic action from working properly. The foreign material which can accumulate in these areas (in my opinion) is predominantly rust and fuel varnish build-up. The problem is: cleaning out this material with "conventional" methods doesn't address the cause.
Two critical functions must be considered when tackling the cleaning:
1) A strong solvent must be introduced to the galleries to dissolve the "varnish" which will release the "rust".
2) A method to remove the "solution" must be implemented and in a specific order of application!
Most of you know where I'm going with this :whistle: and I'm not going to disappoint you. The Cleaning Tool !
"The Three Dragons of Mikuni do not do well when stuffed-up with a cold.
Think of lacquer-thinner as their Dristan® and the Cleaning Tool as the spray-bottle ! .............. 'Nuff said !
I do have a question and it's based on your wording.
After all that; 4 of 6 main jets still blocked solid, needed jet reaming tools to clear.
All emulsion tubes had almost all side drillings still blocked solid, again hand tools to clear.
It sounds like your cleaning efforts were with the carbs partially assembled. Q. - To what extent did you disassemble ?
it's also a good practice to clean-as-you-go, in other words solvent / air-blast each part as you reassemble, that way the risk of any new / recent dust / dirt being introduced is minimized
I could not agree more !
Thanks for being candid !

Yes agreed, I'm now (retrospectively of course!) of the view that most super-duper cleaning methods are bloody useless!!

All my jets / emulsion tubes (aside from the brass-tube choke jet and the float bowl choke jet that appears to pressed half way to hell) were stripped and cleaned loose, along of course with all float valves etc. Diaphragms removed and hand cleaned only, to prevent anything soaking / dissolving the rubber.
I left the butterflys and spindles in situ, and lightly oiled their bearings afterwards with WD40.

In the main carb body that leaves any 'internal' factory jets that are inaccessible (I think you guys were discussing something recently) and of course the small orifices, which I've only soaked and blown solvent through to establish there's a consistent exhaust pattern (by covering / blocking opposite access paths and pumping through with modified solvent nozzle), but certainly this doesn't establish that the inner bores are clean or at their original IDs, time will tell.

I agree about the blockage scenarios Scotch, as even ultrasonic and it's high-temp micro bubble doo-dahs rely on fluid actually getting in there in the first place, so if you have a gallery (especially small bore) blocked at one end, you're relying purely on the way you rotate the casting as you place it in the fluid to get fluid to flow into those air-locked blind-alleys, and that's just too much of a gamble.

A mate of mine in the same workshop is restoring a 50s TVR and he swears by ultrasonic cleaning of his multiple sets of SUs.
I now swear AT it, and have always considered SUs to be like comparing a plough to a combine in the worlds of decent carbs!


I must admit I ended up hand 'reaming' all the jets and emulsion holes (with a set of carb cleaning needles) more out of frustration than anything else, once I'd seen the 'results' of all that prep (not).

I'll also admit to being aware of your bespoke cleaning tool and it's logic, and only failed to buy one out of laziness! Not even a cash issue, as this thing has already cost most of a grand in parts before I even started!   : )


The context of my work thus far is that I'm not doing any cosmetics at all, it's a rusty 70s rat that I only intend to get running, reliably, then assess the genuine state of the engine before deciding whether to go the route of further resto or just a fun running rat for day-to-day.
(I did the same with an old XS11 a few years ago and it happily took me around France in the company of two ZX9Rs, but hell was I burning some oil at those speeds for a couple of weeks!).

So the carb prep in a way is only as much as required to allow me to run it once I've figured out (next job) the cause of the 3 cylinders low compression.

So the carb prep in a way is only as much as required to allow me to run it once I've figured out (next job) the cause of the 3 cylinders low compression
I think this is the first mention of the 3 low compression cylinders. Let me guess cylinders 1,2&3 ?Only because when the bike is left on the side stand, those are the 3 lower carbs and if they flooded............. hydraully locking the left three cylinders........ bent connecting rods.....ouch.  Not the first time hearing of this, and unless we get the carb floats attended to in a timely manner. Hence the reason Scotch is soooooo keen on the carbs with new fabricated brass floats available and the "Cleaning Tool" !! 
I believe the ethanol in the gasoline has mucked up a lot. Those who have delved into the carbs have probably seen evidence of a white powdery substance which is an oxide directly related to the effects of the ethanol which cause the absorbtion of water into the fuel which then sits in the carbs and oxidizes the aluminum. I believe ethanol is "the root of all carb evil" Ethanol fuel which is more than 6-8 weeks old is considered "stale fuel" unless it has been treated with Fuel Stabilizer  for Ethanol based fuels. Sta-bil 360 marine is one example and I use it religiously in everything which I leave gasoline in like the lawnmower, snowblower, grass trimmer and especially my 928 Porsche. All of these engines sit around here for weeks (sometimes months) on end. When ethanol enriched fuel sits around in a fuel tank which is vented, the fuel tank "breaths due to expansion and contraction, drawing in atmospheric air which contains humidity. The ethanol then absorbs the humidity to the point of saturation and then water droplets form and the rest of the story you can read when you pull the carbs apart.

I can't yet add to a direct experience with a running KZ, but it's otherwise related. The same era GL1100 was giving me lots of trouble, running on three sometimes just two cylinders on a start up sitting just overnight! That would correct itself after 10 - 15 minutes riding, but sometimes would happen again out of nowhere, then go away again. Even treating the carbs with Seafoam stopped having much of a positive effect. I was running on regular 87 gas containing up to 10% ethanol. The carburetor job was imminent and I pushed riding a 'dysfunctional bike' to the limit. Than I switched to ethanol free gas. The difference was soon eminent. The bike ran smoother. On start up improvement too. The occasional hiccups returned, but with time less and less and I've been using ethanol free gasoline religiously, with sometimes Seafoam every three or four tanks.

So, what happened next? Despite parking the bike outside, rain or shine, with periods of time having it sit without starting for 1 - 3 weeks, I've never had starting or running bad problems again! Never through the winter, and now we have July. The same set of carbs is on the bike and never been taken off, fixed by the miracle of ethanol free fuel!

So what am I planning for the KZ1300? Of course ethanol free fuel, and it will be a good head start with the freshly rebuilt set.