stock 1978 kz1000 but it has a "Kawasaki by Kerker

I inherited this 1978 kz1000-A2 and it was a mess in the carbs, cleaned them up. (was sitting for 12 years under a tarp).

The old gentleman I got it from said it was all stock except the 4-into-1 exhaust -- and the pipe says "Kawasaki by Kerker" -- I don't remember it but I guess back in the 1970s, Kaw had some arrangement with Kerker. The pipe looks just like a regular aftermarket Kerker pipe from those days.

So the carbs: all stock jetting. He said he just put the Kerker on and didn't change the jetting at all (probably will run lean once I get it running again!)

The airbox: all stock *except* the rearmost large, black plastic 'snorkel from outer space' is not there. I know what this missing piece looks like as I owned a brand new 1977 kz1000 back in 1977. This plastic snorkel box connects to the actual airbox that has the air filter element in it. This (stock) snorkel box is not on this hand-me-down '78 kz1000, only the stock air filter + air filter case is there with the stock carb boots, etc.


I betcha the bike will run lean -- what pilots and mains should I go to? In my view, there are 2 factors:

1) more air coming into the carbs due to the missing black snorkel box

2) more air flowing out at the exhaust part of the 4-stroke cycle due to the less restrictive Kerker.

Any ideas what # mains and what pilots to go to?
Or any other changes I'll need to make?

Thanks! I sold my '77 kz1000 when I went to college and I'm really looking forward to getting this one going!

here you go.... OEM Kawi jets for KZ carbs...

Now keep in mind, with that Kerker they most likely re-jetted...

As for being lean, review below what was OEM stock jet sizes (OEM exhaust) and compare to what you have in there now...

do you have a chart like this for a 650?

I've got the same bike with 4-1 Kerker w/street baffle. Stock airbox and filter. I have 17.5 pilots and 110 mains. Runs very nice.

Thanks, I'm going to 17.5 pilots and 110 mains!
If that's your machine I like the color.

Thanks, yes it's mine. Bought from the original owner in '93. If your bike is like mine, it is very cold-blooded and soft on the bottom end with the 115 pilots. With the 117.5 pilots, it will warm up more quickly and be much more responsive off-idle.

The 'more responsive off-idle' sounds very welcome -- my 1977 kz1000 with a less-restrictive exhaust but stock jets had that problem. This 1978 bike isn't running yet but it will be soon, and I have one question -- what's a good source for cheap jets for these carbs? I can get them from the local Kaw dealer but (surprise surprise) man, they're not cheap.

Thanks for your help. Wish my '78's paint looked like yours!

I got mine at Z1 Enterprizes. I don't think you will find a better price and service. I have bought a lot of things from them and have never been disappointed. Their shipping time is amazing.

Keep in mind that altitude makes a difference on what jets to use. Just because one person has a certain size jet doesn't mean yours will need the same size. Best thing is to take a plug reading.

I forgot all about that part!
I'm at sea level in Silicon Valley, so there's more
air here than, say, Denver -- that means the amount
of gas will have to be increased to match the extra air.

Here's my thinking: this '78 kz1000 was gotten from the original owner who rode it here in Silicon Valley its entire lifespan, and the bike was bought at the local Kaw dealer in 1978, so it probably was set up for sea level.

That means probably has 105 mains and 15 pilots in it based on Mr. O.M. Rock's chart above, but I'll check that today when I retrieve the carb bits out of my Berryman's carb cleaner.

If I find that to be the case, the suggestion of going to 17.5 pilots and 110 mains may do the trick, as the amount of extra air flow is probably minimal on the carb intake side -- what with the stock airbox and filter still in place. The only thing missing on the airbox side is the black plastic snorkel box that connects to the actual airbox contains the air filter element. With that exception, everything's stock: carb-to-airbox rubber boots, airbox, filter element.

And the 'Kawasaki by Kerker' 4-into-1 is a street-baffle (not a racing-baffle) pipe, so the 110 mains (up from 105) may also be fine, as the exhaust is not flowing a ton of extra gas volume over the stock pipes (I'm guessing here).

HOWEVER -- from my 2-stroke street bike experience, we always tried to figure out what larger jet sizes to go to for our engine mods then we went up one jet size larger, then checked the bike out, then reduced the jets until we got good plugs readings. It's really critical on a 2-stroke because every time the piston moves to the top of the bore you get ignition, whereas with my kz1000, it's a little cooler in there, piston only fires every other time.

So.....guess what I'm asking......is it wise to maybe go up to 115 mains, and maybe 20 pilots, then drop back to 110s and 17.5s if the plugs are rich with 115s and 20s?

I haven't ever personally rejetted a 4-stroke motor, only 2-strokes. I always let mechanics do the 4-stroke rejets for me.

hi guys
i've just bought that 1982 kz1000
- mikuni 34mm
- k&N pods
- 4 into 1 exhaust
- carbs mixture screw 2 turns out
- floats ajusted 17 mm
- pilots 17.5
- jets 132.5
- needle jet in mid-position (third of 5)
and the carb is clean

theses are my symptoms:
on neutral, rpm 0 to 10k everything perfect

in gear when accelerating

rpm 0.750k to 4-4.5k everything's running good than it 5k start burping like crazy even full throttle no respond i tried also to close the choke while running ... to increase the amount of fuel no respond

after i drilled the jets with a 1/64 inch drill bit OMG ! worst worst worst !

is it a problem of jets and pilots setting or i would say its look like a fuel pump problem ?

im lost what i should do?

thanks

Start your own thread would be a good thing.
Your missing some needed details to really get going.
Mikuni 34mm what? BS I'm assuming...
What Jets did you drill?
Do you have a shop manual for this bike?
barkers41 wrote:

hi guys
i've just bought that 1982 kz1000
- mikuni 34mm
- k&N pods
- 4 into 1 exhaust
- carbs mixture screw 2 turns out
- floats ajusted 17 mm
- pilots 17.5
- jets 132.5
- needle jet in mid-position (third of 5)
and the carb is clean

theses are my symptoms:
on neutral, rpm 0 to 10k everything perfect

in gear when accelerating

rpm 0.750k to 4-4.5k everything's running good than it 5k start burping like crazy even full throttle no respond i tried also to close the choke while running ... to increase the amount of fuel no respond

after i drilled the jets with a 1/64 inch drill bit OMG ! worst worst worst !

is it a problem of jets and pilots setting or i would say its look like a fuel pump problem ?

im lost what i should do?

thanks