TOPIC:

hey guys, my 81 1000ltd is giving me a few fits yet. its almost an act of congress to get this thing started after its cooled down. once it does fire up, its a piece of cake to stop and restart it until it sits for few hours. its got a new battery with a good charge on it, no vaccum leaks that i can detect, good spark at the plugs, but its just a cold blooded mother. some times priming it helps, other times not. kinda at a loss here. would the relay trick for the carbs be good start to livin up the coils abit? carbs arent really my thing and i have a hard time getting them set right. but its got new pod filter, 4-1 header with what you might call a baffel, and j model carbs on it. im going to try and block off abit of the pods to see if knocking down the airflow alittle might help, but im abit lost in this area. any help would be greatly appreciated.

What do your plugs look like? They could at least tell you generally are with mixture.

kzcsi

they have afairly nice tan color to them, pretty white, could be border line lean. i did try spraying alittle carb cleaner around the rubber mounts, 1-3 stumbled abit, so i know theres a small air leak ther(very slight) but i wouldnt think that would contribute alot to hard starting. i did also notice that if i turn on the choke fully and crank it abit, then turn it off and stay off the throttle, i had alot better chance of getting it to come alive. got the relay thisafternoon for the mod, going to try that, it doenst seem to do anything but to help so its worth having on there anyways.

My GPZ was very difficult (almost impossible) to start cold. I cleaned the carbs a couple of times and that helped but what really did it is getting the valves adjusted. Huge difference. You may want to check...
Good luck,
Jim

had the valves cover off and checked two days ago, biggest clearance was .004, smallest was .0025 so they are all in spec. the po put on pods and a near open 4-1, i think this is my main issue. he said the carbs were off of a j model which are suppose to have 127.5 jets in it. i just think my main issues are the jets. i had a cb750 that i had pods and mac open drags on, it did about the same thing(hard starting and popin out the pipes). im ready to order some new jets and try to get this thing calmed down, but im lost as to where to start for sizes. it was suggested to go to +3 on the mains and +1-2 on the idle jets. but if this is the case, it should already be in that area. someone on the board here said the stock jets for the carbs should have been 122s i believe. so... i should already be up +5 on the mains(not sure where the other jets are at). the jets in the carbs arent marked so im not sure if they are even stock or not. dealing with the old cbs, it just seems like 125 jets arent big enuff. im used to kehiens, so is there a diff in the way they are sized between the two types of carbs?(is a 125 minkuni jet the same size as a 125 kehien) i would think i would want to be in the 130-135 range. im half tempted to tape off half the pods and stuff something in the pipe to see if restricting the air flow will have any effect.think ill give that a try and see what happens today. i appreciate the suggestions guys, very nice board and friendly guys willing to help out. hopefully i can get this thing running right and youll have converted me from the dark side of cb750 loyalty!thanks guys for the help

While different jetting may improve on-the-road performance, IMO they're not going to alleviate the hard cold-cranking difficulty. The enrichener (choke) has it's own separate independent circuit inside the carb, which depends very little if at all on size of either the pilot jet or main jet, and is designed to operate with the throttle being left alone in fully closed position. And the small air leak will indeed disturb the enrichener mixture by leaning it out.

Would use strobe type timing light to double-check ignition timing and operation of the advancer unit. Check for continued good fat spark at plugs.

Measure voltage across battery terminals at idle rpm (look for 12 volts) and again at 3-4000 rpm (look for 14-15 volts). Important to also measure voltage at the coils to determine extent of any drop in voltage between battery and coils. If there's only very little voltage drop, may omit the coil wiring conversion, at least for now. Low voltage to coils means weaker spark which contributes to a more difficult initial cold crank-up.

Glad to hear that the valve clearances are up to specs. If not already done, would also do compression check (remember to hold throttle wide open during testing).

And assure that an ample supply of good fresh fuel is reaching the carbs. With no crud obstruction in petcock, petcock screens, or in-line fuel filter.

Even perfect carbs can't compensate for deficiencies in these other areas, any of which might be responsible for the cold-cranking difficulty. That's why the manuals instruct addressing the carbs last after doing all the other tune-up procedures, including brand-new spark plugs. And most manuals advise against any carb fiddling absent first doing the all the other tune-up procedures. Otherwise the carb work is likely just wasted effort and will need to be repeated later.

That said, one "permissible" carb test anytime is to measure the service fuel level inside the float bowls, using the clear plastic tube test. Float bowl fuel level being too low will cause excessivly lean mixture (including the enrichener circuit), regardless of otherwise perfect carbs.

Good Luck!

checked the floats= good
plugs= new
coil volts= 11.4
valves= within specs
timing= to be continued
fuel= as clean as i can get it, used a two liter pop bottle as a tester to make sure everythings clean.

without touching the throttle, i used full choke and the bike did start without priming it, it popped and cackled for awhile before it warmed up. with the choke being independent, will it still supply the correct amount of fuel to get the bike started even with the pods and open pipes? i know it will start, but with the higher air flow, will the choke dump in enuff to compinsate for it? or is the airflow only going to matter off idle? i know theres a jetting issue also, going down the street at a constant speed, the bike will burp untill i let off the gas abit, kind of sluggish off the throttle and back fires like a mother if i just crank it open, then takes off. but with no where the power it should have. i hate carbs.
im sure you guys aright about the jets not being the main thing, i have a hard time getting my brain past that because i know its an issue and i just want to keep blaming that. i hate thinking there two problems at once i guess lol. anyways, ill try and get the boots all sealed up and go through the carbs again, hoping its just a bit of crap in the choke system as you suggested. is there going to be any issues if i put alittle tiny bit of silicon around the boot mount to seal up that little vacum leak? its so very slight i was hoping that might be just enuff to cure it.

Thanks for the report.

IMO the pods and open exhaust won't adversly affect function of the enrichener circuit, and attempting to seal the carb holder with a little silicone won't hurt anything. But brand-new carb holders should be at top of wish list. Click here > New Carb Holders from Z1E

And believe it would be ill-advised to partially obstruct the pods as a means to enrichen the mixture.

Wondering if the previous owner was correct about the main jet being 127.5 (up from 122 stock) on J-model carbs. (constant vacuum aka CV carbs, as opposed to manual throttle slide carbs)

When re-cleaning the carbs, would check for pinhole or other leak in diaphram by holding it up to the light.

And there may yet be some blockage in one or more of the pilot circuit passages.

Question -- Have any adjustments been made to pilot air screws, and with what result? Some enrichment here might improve performance at idle and during first 1/4 throttle range where the pilot circuit influences the mixture. It's surprising how fast these bikes easily cruise with only a 1/4 throttle opening.

Perhaps someone better acquainted with this model's ignition advancer system will offer some advice as to whether it's possible for it to "get stuck" in the advanced position which could cause hard starting and poor idle. My experience is with the older advancer unit with springs and centrifugal force weights.

Good Luck!

i really appreciate the advice patton, keep it coming. im sure well get it figured out sooner or later. i checked the diaphrams and they looked good, nice and pliable no holes detected. the screws were turned out 3 1/4 turns, little much isnt it? thought they were supposed to be 1 1/4. didnt get to that till i took the carbs off for another cleaning. i looked those jets up and down and couldnt find any marking to dictate the size. ive still got the stock airbox for it so im thinking to try that on and see if there is any differnce. no lid and no filter, kind of looks like itd suck more air without anything restricting it. i mentioned blocking part of the pods because on my cb750 i had a one piece filter that was letting to much past, i duct taped up the top half of the element and it made a huge difference, then i went to jetting. just used that as a test to see if that truely was the issue. i took all the jets out and cleaned the carbs very well, ill put them back together and get them in today for a test run, there is the little jet under the plug next to the main that i left alone, is it ok to pull the plug and clean? ill wait for a response before i reassemble, dont want to get them together and find those are plugged also. the manifold are actually in pretty good shape, no cracks and still pliable, just sucks a very little bit at the connection with the head, ill try siliconing that and see also. again thanks for the help guys, this thing would have been heading down the road long ago without the advice im getting. very helpful.

there is the little jet under the plug next to the main that i left alone, is it ok to pull the plug and clean? -- does it appear on this diagram as shown by Kawasaki.com for the 1981 KZ1000LTD? (The J-model looks basically the same to me ).

it looks to be the #92064. mabe ill just leave that alone for now. i was on z1s site and ordered a bunch of mains to try and test with later, but i couldnt find any pilot jes for my carbs(or any for that matter). is this something unavailable? i read a couple posts that guys drilled them out, but that seems pretty risky to me, mo so if i can find a replacement.

the screws were turned out 3 1/4 turns, little much isnt it? thought they were supposed to be 1 1/4. --- If meaning the pilot fuel mixture adjusting screws, that would indeed seem to be way too far out. Maybe having been so set in a desperate earlier effort to enrichen the pilot circuit mixture. Wondering if there're out so far as to allow leakage of outside air into the supposedly richer mixturer and actually causing a leaner mixture -- just guessing -- and thinking these adjuster screws may be nearing their thread limit and on the verge of falling out of the carb .
Would set these back to initial specs per FSM (1.5 turns out from lightly seated sounds about right, but would go by the manual).