Z1OwnersClub GB

Just setup the carbs on the Zeph. Without the workshop manual I set the mixture screws to 1 1/2 turns, put the mercury gauges on and got the sync to within 1.5 cm after setting the revs to 2K but whilst doing this I noticed that No. 1 carb has a spit every know and again and the vacuum dropped at the same time. With the tickover set to 1100 It hangs slightly when the throttle is blipped, then returns to idle, then the revs fall and it stalls. Took the plugs out and cleaned them, also swapped them around but with 8 plugs I wouldn't expect a problem. The issue stayed on No.1. It seemed 'chuggy' until you get to 3K on the road. I may be remembering wrongly but the first one I had pulled from 30mph in top very smoothly. I've ran it with one plug out and it didn't spit and the spark was very blue and constant. I've read that this may be a lean setting so I've unscrewed 3 off them out a further 1/2 turn. 3 because I'm going to need a special tool to get to No.2 because I can't get access due to the alternator being in the way.
Does anyone know the standard setting please, I've read 2 turns out but without the factory manual I'm not sure.
Also any clue as to where to start looking regarding the spit. This is with a warm engine.
Cheers

Its likely to be either an air leak at the carb boot or pilot circuit of number 1 partially blocked or intermittently blocked. Easy to check if you adjust the air screw of any other carb and see how much 1 turn for example makes to engine revs and noise and do the same for number 1 to compare. Sorry i dont know what the standard setting should be, but using modern flame retardant petrol, its likely that they may all need an 1/8, 1/4 or even 1/2 a turn out more than standard!! My CV's (similar thing) would pop and spit just a wee bit when they were perfect or a little on the lean side. Richening them up doesnt give the same power characteristics low down but does stop them hunting and does bring the revs down just that bit faster. They were also less inclined to stall on shut throttle.

AL

Thanks Al. It shouldn't be any air leaks. It's got new genuine carb to head rubbers with new o rings. I'll have a play with the other carbs as you suggested to gauge the difference.
Just been for a blat down the road and it reminded me of my youth, on a z250 with a damaged carb membrane. I didn't take the tops off on purpose so as not to damage the membranes when I cleaned the carbs. Hope it's not the membrane, 132 squid from genuine with slide.

Hopefully it wont come to this but these lot specialise in diaphragms.
https://www.nrp-carbs.co.uk/kawasaki_ca ... hragms.htm
As a matter of interest what mothod are you using to clean spark plugs?
I read it in youre first post.

AL

Went to carry out your test Al, the bikes been on it's sidestand all night and I could smell petrol. No 1 was leaking out of the Pilot and main air jets, presumably because that becomes the lowest carb on the sidestand. Carbs off. Fitted some clear tube to the drains and checked the fuel heights. All of them are about 5mm above the mating surface.

I'm unsure what the height should be but am guessing this is too much. I've read elsewhere that a provisional measurement of 17mm should give a rough idea when the carb is angled slightly upside down so as not to put too much weight on the float valve....they are 17mm but this doesn't guarantee fuel height.
On other thing, does it matter which way round the float valve is placed regarding it's 'ears'?


Thanks for the link, its bookmarked.
I have done a resistance check with my finger on each slide, they all feel the same and are constant, so hopefully not the diaphragm.

If they were CV's as in Mikuni BS34 the fuel level is 3mm + - 1mm below the gasket face of the body from memory. Cant say for CVK from Keihin but 5mm above looks like asking for trouble but it may be the case. Reading another thread the level on another bike was at the gasket face and the owner seemed happy with this concept but that may not be factory either. It looks like you have a serious fuel leak problem to fix before the spitting habit gets fixed in any event.
What is odd though is that with the fuel level appearing to be potentially too high, the fuel level available to the pilot circuits should be excessive and you should be getting an overly rich condition and not a potentially lean one. Confusing.

If you can find the correct fuel level setting it is best to do it on the bike with the engine running in the manner you have done statically with the clear tube on the drain outlet.
Whilst there; if you leave the tube attached and fuel tap open and engine off. After a period of time has elapsed you can see visually if any are passing at the float needle valve if the level in the tube increases.
Similarly; if you (under the same conditions above) run the tube down into a container, after an initial surge of ten seconds of full flow fuel, you can assess the recharge rate for each float and float valve arrangement. This will give a good visual representation of the speed at which each bowl replenishes itself. Relevant because; some cabrs have a limiting stop at the bottom of the bowl and it is possible to adjust the floats to be almost trapped between the two limits and end up with diminished dynamic re-fill even though the static fuel level may appear to be spot on.

General consensus is pilot air screws at; 2 turns or a touch more from fully seated but again it would seem dependent on the market they were sold into and the prevailing environmental legislation in force in that country / continent.
Dont know about ears on the float needle.
AL

Thanks Al, I saw on another site (same carbs different bike, think a twin) no more than 1mm above the carb body so I've gone for that. I've set one carb up now at + 0.5mm so will measure the float height with a depth gauge and reset the other three the same. Should give a ball park setting to allow me to wet set them, then leave them off the bike with fuel on to see if the levels creep up, then have a go on the bike.
Never thought of doing a dynamic check with the engine running, that will be the final confirmation, and as you said, leave the tap on prime for a while to reconfirm the valves aren't seeping.
Now the carbs are off I've also set the screws to 2 turns.
Thanks very much, much appreciated.

Got 3 of them sorted but 1 won't turn off and floods. Swapped the float and valve with another carb and it stays with the valve. The float doesn't look damaged and I've done a shake test to see if there was any fuel inside. Looks like a new valve needs to be ordered.
Is it worth biting the bullet and replacing all 4?
I've read that it's pointless going for aftermarket ones as they can be more trouble than they're worth?
120 squid for 4 valves! I hope they set the float heights and sync the carbs for that money!!!

Bought four new ones for the CV's some years back but because they were shit i ended up just using the 'O' rings leaving four very expensive redundant needles and seats sitting in a box!
Having been bitten that time and having a leaky one on the bank of RS carbs i bought just one genuine one and replaced that.
I have a thought to share with you.
Unless you are the manufacturer or have fingers of a pixie you cant tell what constitutes a weak spring on the float needle plunger pins. It was apparent that if you placed them plunger pin to plunger pin against each other you can see if one deflects more than another. In my case the leaky one was very soft compared with the other three. When the new one arrived i did the same thing again; plunger pin to plunger pin and confirmed that three were the same as the new one and the leaky one was puny by comparison.
RS flatslides were three years old by that time so what hope for original parts at 20 years old +.
AL

Thanks Al, just done the plunger test. The flooding carb was the weakest but closely followed by one other. Put them back together and connected to the remote tank and now I have two flooding, and yes the other one is the 2nd weakest. Just looked around at prices and Webike have them at 17 euros each, the postage is 20 euros but at 90 euros to replace all 4 and save the grief, time and swearing I'm tempted to replace the lot. As you say the bike is 26 years old. To replace 2 from kawasaki is 60 euros plus p&p. At least it should give me peace of mind. Also I should have nice souple rubber tips.
Would you concur?
I've got new Keyster bowl gaskets as well, not impressed. They've only been on for 5 minutes and they are now oversize and need tempting in to place with vaseline.
Thanks for all your time and guidance so far.

Just found a manual on line thanks to Big Fluff's post in the tech section. Pilot screw 2 turns out, fuel level -0.5 to +1.0mm.

Not familiar with Webike or the quality standard of their parts but i think that my experiences of aftermarket (even guaranteed) parts leaves me with the impression that; where genuine is available; that would be my preference. In youre case, two genuine ones, in theory, guarantees to fix the two leaky carbs, whereas four repro's, could lead to four weepy ones!!
Assuming the cause is not the 'O' rings round the float valve seats of course. Interesting that the valve seats dont appear to have any means of retaining them. The CV's and RS's have a flat 'fork' and screw to hold them in place.
The RS float bowl gaskets are similar, i guess, to the CVK's, being; moulded firemans hose (licorice for people of a certain age ). When wet they; as standard, swell up and are a git to get back in. These are genine new ones in new Mikuni carbs and genuine replacements too as i nipped one putting it back in. They do return to nearer normal size as they dry out though. I am told that you can stitch them in with superglue but dont fancy the idea myself.

AL

The parts are OEM apparently
https://www.webike.fr/products/24383733.html
Ah, didn't realise the rubber float bowl gaskets swelled, good to know.
There is no 0 ring on the float valve seat, which is pressed in, according to the parts drawing on CMSNL
https://www.cmsnl.com/kawasaki-zr1100a3 ... LT1YLczaUk

I've stitched an o ring with superglue years ago. It was the head gasket on a set of TZ350 barrels that were in my LC. We had the O ring on a long roll at work.
Just need Webike respond to my email now....

Got 2 Kwak needle jets from Z Power. What a difference in spring strength. Fuel levels now set. Got them back on and balanced to within 1cm. No 1 was still having a cough, not as bad though. Unscrewed the pilot out 1/4 of a turn and it seemed a lot better. Still a bit chuggy between 1 and 2K rpms and the tickover can be set to 1K but if I nip down the road when I stop the tickover goes down to 500 and will stall when the throttle is blipped.
I've got access to a Colour Tune but it's for standard size plugs so looks like a plug chop job coming up.
The tickover wanders around a little also.
Above 3K it's absolutely fine so something on the pilot circuit is a miss.

With an identical set of issues with the CV's; I blew out backwards with compressed air, sprayed carb clean, WD40 and anything else i could find, and ultimately ultra-sonic cleaned about six times with the bodies orientated to favour particles and dirt tracking backwards from the narrowest part of the drilling (its exit point in the venturi) to the atmospheric mouth in each case. Clean again with clean water and blow out again. Re-Sealed the; blind drilling ball bearing 'stops' with a tiny smear of araldite where this had fallen off in the US tank. Checked continuity of flow with the WD40 again and again with compressed air. Did that make all the pilot fuel screws the same or as per standard? No. Standard is something like 1 and 1/4 turns open and i think they were all around 2 turns out with a range of 1 and 3/4 to 2 and 1/8 ish and it ran absolutely perfect from that day on.
You will only be able to do this with a colour tune. It tells you everything you need to know and in real time. No amount of plug chops will give you anything like as much info for as little effort. You also need to use new virgin plugs for a plug chop which brings me to another point. If you have had flooding carbs or have cleaned youre modern spark plugs with a shot blaster or wire brush they are likely fizzed. Unlike old ceramic plugs they are very porous at the centre insulator and are designed to be replaced at lengthy intervals in modern lean burn engines.
Noticed yesterday that you can buy an adaptor to take the standard 14mm colour tune down to either 12mm or even 10mm.
https://www.ebay.co.uk/itm/131051252158 ... %3A2334524

AL