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TOPIC: 1977 KZ1000 LTD carb bench sync questions...

1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #525810

  • 74ullc
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I'm trying to find out the correct method to bench sync the carbs on my 1977 KZ1000LTD. I bought the Haynes manual for the 73-77 900 and 1000 fours, mostly just for info on the carbs on my bike. The carbs in that book are not the same. I believe I have VM26SS, they are stamped

101
7B

on the flanges.

I remember reading a thread that said to adjust them using a piece of wire or drill bit pinched between the carb throat and slide. I believe the method was to adjust them to where the wire/drill bit just falls out with the carb laying on its back. I cannot remember what size wire/drill bit to use. Is this correct and what size wire/drill bit should I use?

Just trying to get them close until I get a set of vacuum gauges.

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Gulf Coast, Texas
1977 KZ1000LTD
1984 VF700F

1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #525813

  • PFD
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My kz1000 factory manual says to use a 0.7mm solid wire, place it between the bottom of the carb bore and the throtle valve. Turn the adjusting screw slowly out till the wire falls out, repeat for each carb.

I know guys will use the light method, lower the valve to the bottom. With a light behind the carb slowly raise the valve up till you can see just see light through the bore, repeat.

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78 Kz1000A2, 77 Cb750K daily rider, Tattooer, pinstriper and signpainter
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1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #525816

  • 74ullc
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Thanks for the info! .7mm is 27 thou. I found some wire on the workbench that is .030, close enough I bet.

Does the book make note to place the wire on the engine side of the carb? Looks like the engine side closes first.

I just looked through my carbs using a light like you said and there is no gap at all in any of mine. Looks like the P.O. set them to fully closed. Seems like setting them to fully closed would be ok? Wouldnt that put them all the same? Maybe setting them fully closed messes with the WOT setting?

edit....looks like the idle stop screw has to be turned in some for this to work. About how much is correct or is it just an enough to do it setting?

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Gulf Coast, Texas
1977 KZ1000LTD
1984 VF700F
Last Edit: by 74ullc.

1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #525821

  • PFD
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The manual has a 1.6-2.0mm gap at the throttle cable bracket and the stopper on the pulley, in regards to the idle adjusting screw.

Engine side of the carb is the side for the wire, the manual doesnt say so but that side closes first by the looks of the diagrams.

Setting the throttle valve all the way down will most likely not allow enough air into the body of the carb, the normal vacuum gauge reading your after is around 20-28 cm Hg according to the manual. I'd expect the .7 wire gets you close to this reading, close enough that all 4 carbs are in relative sync and the bike will start and idle well enough to hook vacuum guages up and do a proper sync. If the throttle valves were all the way down there wouldn't be enough airflow through the body of the carb at idle, correct me if I'm wrong. I'm no carb guru but it's all based on airflow.

At idle the throtle valve restricts the flow of air through the carb bore, keeping the low pressure (suction) created by the engine happening. The idle circuit operates on the low pressure end of things, once the throttle valve raises and the needle comes up it goes over to the main air jet and main system. Which is after 1/4 throttle from what my manual says. I'm not completely familiar with Mikuni's, coming more from Kehin's and Honda cb750's but the principal is pretty much the same.

Hope this makes sense, if you don't have a factory service manual you should try and find one on eBay. Pretty good breakdown of how the carbs work and set up.

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78 Kz1000A2, 77 Cb750K daily rider, Tattooer, pinstriper and signpainter
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1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #525844

  • TexasKZ
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There are also some good carb tutorials in the file base on this site.

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1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough

1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #525850

  • mark1122
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74ullc wrote: Thanks for the info! .7mm is 27 thou. I found some wire on the workbench that is .030, close enough I bet.

Does the book make note to place the wire on the engine side of the carb? Looks like the engine side closes first.

I just looked through my carbs using a light like you said and there is no gap at all in any of mine. Looks like the P.O. set them to fully closed. Seems like setting them to fully closed would be ok? Wouldnt that put them all the same? Maybe setting them fully closed messes with the WOT setting?

edit....looks like the idle stop screw has to be turned in some for this to work. About how much is correct or is it just an enough to do it setting?


.030" is fine. 1 slide will not be adjustable. its often carb #2. u can use the idle adj screw to get it to .030", then u set all the others to match it (.030")by adjusting the slides from inside the top of each carb, as described in the manual.

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1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #525903

  • 74ullc
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I got them set very even now! Thanks for the help guys!

I was having problems getting them to set with enough adjustment on all of them to lock them down. One carb, #1, was giving me lots of trouble.

Turns out that the little stamped connecting plate inside the slide was bent/twisted. I removed the slide and got the plate straightened out and then the job was easy. Looks like maybe someone tried to get the slide out with the arm still attached to the rod and bent it during the process.

The bent plate was causing the #1 carb slide to be much higher than the other 3 carb slides with the screws set evenly. I was having to set the #1 carb with the screw almost all the way down and the other 3 with the screws all the way up. There was no room to adjust them any further and still have them sync up correctly. Thats why I was having so much trouble with the idle screw setting also. If it wasnt just right I didnt have enough adjustment on all 4 to get them to lock down.

When I bought the bike in March the PO told me he had tried to sync the carbs using vacuum gauges and was unable to get them to sync. Between the bent plate in the slide and the way the carb boots were leaking its no wonder he wasnt able to sync it up. Now with the slide plate fixed and new carb boots I bet it will sync right up.

He also had the fuel level in the bowls set to just above the bowl gasket level. All four floats were set very even even but set so the fuel level was about 3/16" too high. I used the clear tube method to get the fuel level dialed in 3mm below the carb base.

I'm going to get my hands on a good manual. There are some listed on ebay from New Zealand. They claim to reprints of the factory manual, including the supplement for the LTD bikes all in one book.

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Gulf Coast, Texas
1977 KZ1000LTD
1984 VF700F

1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #526011

  • Kawboy74
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Don't worry too much about getting the exact readings with vacuum gauges as I found it can vary depending on whether you have original air box and filter,exhaust etc. because as it breathes better these numbers seem to change.If you have the link plates between each set of carbs you have the '73 to '75 carbs and they will bend easily so only a little pressure is needed when tightening the lock nuts on top. An old manual or factory manual is great to have as others have stated and have invaluable info to use.
Good luck!
David

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1978 KZ1000 B2 LTD fully restored with original exhaust,Dyna pickup
1974 Z1A As original as I could get it
'88 ZX750R braided lines, mostly original
KZ1000 project on the bench
Burlington,Ontario

1977 KZ1000 LTD carb bench sync questions... 5 years 1 month ago #526238

  • 74ullc
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Kawboy74 wrote: If you have the link plates between each set of carbs you have the '73 to '75 carbs and they will bend easily so only a little pressure is needed when tightening the lock nuts on top.


I'm pretty sure mine are VM26SS, they have 101 7B stamped on the flanges against the plate. I have seen people ID them using those #'s, any idea where that info can be found?

Mine dont have the external sync plates, thats the kind that are detailed in the Haynes manual I bought. Mine are very different than those. I mean the link plate inside the carb, in the slide. Its part of #15 on this page.......


www.powersportsplus.com/parts/search/Kaw...000-B1%29/parts.html

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Gulf Coast, Texas
1977 KZ1000LTD
1984 VF700F
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