Bike boogs above 4k

I have a 79 LTD 1000 with dyna coils, electronic ign,individual air pods and vance and hines pipe. Bike idles good,rev's great,vacuum is @10" on all 4 carbs but, as soon as I put it in gear and hit about 4500 RPM bike boogs down,(gargle's). Voltage at the coils is 11 volts. I have 15 pilots and 107.5 main jets, needle's set at the 3rd groove. This is driving me crazy. I tried 20 pilots and 110 mains but bike seem to run rich. Oh yea fuel level is good I used a hose laid along carbs and turned fuel on for each carb.

Does anyone have any ideas. Advice is appreciated.

Stock air box ? Carb holders good ? No air leaks ? What kind of air pods ? You still using stock petcock ?

Failed to notice anything bad about the carbs, but it's bothersome that Voltage at the coils is 11 volts.

Believe should have full battery voltage (12+ volts) to coil at idle and voltage between battery terminals should be 14-15 volts at 5000 rpm. So might be an ignition issue stemming from a defective battery or just that the battery needs charging, or a possible defect elsewhere in the charging system (such as voltage regulator, rectifier, or alternator-stator).

Would assure automatic advancer unit is clean, lubed and functioning properly. And that all wiring connections are clean and tight.

Might be insufficient compression or an ignition issue. Have compression and valve clearances been checked?

As known, engine should be fully and freshly tuned and basically all other components good-to-go before addressing the carbs.

sounds like you need to take the needle clip up a notch or two. pod airfilters are a pain in the ass. if the 11 volt thing bothers you check out the coil rewiring tech sheet on wiredgeorges page. i've been doing essentially the same thing to old japanese bikes for a while. it's a great diagram, particularly as kz's have their coils wired through the kill switch.

I've noticed that many carb'ed bikes have a dip in the torque curve around 4500-5000 RPM. I think that this is related to a lean condition as the carb transitions over to the main jet circuit. Air pods will make this worse. 11 volts at the coils will also make this worse. You'll need to richen up the midrange (probably best to raise the needle clips a notch or two), and install Wiredgeorge's coil power mod, which uses a relay to supply full battery voltage to the coils.

With stock carbs and engine, with pods
and a header,I ran 17.5 pilots and 130
mains.That was on my 1977 KZ1000.

The stock carbs on a 79 LTD are the 26 pump carbs, are they not? These carburetors are pretty hard to tune and your problem appears to be one of tuning. I personally would find a set of earlier VM26s without a pump as they are more straight forward as far as tuning goes. The sooty plugs and "rich" you see isn't the carbs, it is probably low coil voltage and possibly even tight valve clearances. Suggest you have a look at the "wg's Tech Stuff Index" on our website and the tech tips there.

Thanks for the responses. Haven't had a chance to work on the bike. I'll probably work on it tonight. I have bought another set of carbs w/out the accelerator pump but, I'm not sure what size they are. They're suppose to be 26VM's. Does anyone know how I can tell. The sliders look smaller and thicker. I'll try some of the things you guys suggested and let you know the results.

Rweber51 wrote:

...bought another set of carbs w/out the accelerator pump but, I'm not sure what size they are. They're suppose to be 26VM's. Does anyone know how I can tell....

Z1E carb pics


Thinking the oem '77 KZ1000 has VM26's with pilot mixture screw and idle adjustment knob on the carb bottom; and oem '78-'79 have pilot air screws on the carb sides and idle adjustment knob on the top; standard models without accelerator pump.

Could measure the inside carb bore diameter on engine side -- am thinking it will be slightly over 26mm.

Am somewhat uncertain regarding some of the above (and likely to stand corrected).

I remember the idle adjusting screw is on the top. In reference to some of the other items in question. Ign timing is right on, haven't checked the advancer. Advancer should be fully engaged @ 2500 - 4000 RPM right? I just had a valve job done with clearance checked so thats ok. How close to batt voltage should you see at the coils? I may want to rewire as George calls out. And one last thing. The new carbs, whats a good baseline? Pilots 17.5 mains 130?

Thats where I would start.Use tapered
air filters.The straight, flat backed,
round K&N style,would at certain RPMs,
act like they were pulling a vacume on
the back,and hesitate.This was around
4-5K RPM on my bike,and went away when
I changed to the tapered filters.

Since the voltage on the coils was low figured that I would rewire them as on Georges website. Everything looked good until I hooked the red wire for the Dyna S ign. I hooked it to the pwr source for the coils once I did that the voltage to the coils went to zero. Now I'm thinking that I have a wiring problem. Oh another thing, when I set the timing I had to turn the pickup backing plate all the way counter clockwise for the F mark to line up, which to me seemed strange so I checked cam timing that was fine.
So,even with the red wire for the Dyna S system hooked to the coil pwr I should still see batt voltage right? Also, in looking at the wiring dwgs in the Kaw motorcycle service manual and the Clymer I noticed that it looks like the coils are to be hooked up as follows as sitting on the bike left coil for cylinders 1&2, right coil for 3&4. I have them hooked up left coil 1&4, right coil 2&3, which is right?