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Probably the Carburetors
- bubbap
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- Ride it like you stole it!
What's happening is that I can start her up on full choke from a dead cold on the starter for about two seconds and she fires right up. The problems are she won't run off choke no matter how long she has been idling. When I give her some throttle she will die unless I do it really slow then only to 4k. I cleaned the carbs pretty thoroughly, and used replacement kits. I don't remember the jet numbers but I will look them up today, (should be stock). I also need to do the clear tube float test to check them out as well. Any advice would be great!!
Thanks!
1979 KZ650, Mac 4-2 exhaust. Restored after 25 years of sitting. Dyna elec coils, ignition. As old as I am, been in the family since new.
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- Limey
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Also, make sure the carbs are pushed all the way into the rubber manifolds to the engine - it is easy not to seat them properly and get an air leak!
Good luck!
Eric
Newmarket, England (for 3 years)
Pentwater, Michighan (Home)
1978 KZ650
2000 ZG1000
2006 Suzuki Burgman 650
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- bubbap
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needles, main jets, pilot jets, float needles.
I have torn down each carb. and cleaned it in a solvent tank, and carb cleaner.
1979 KZ650, Mac 4-2 exhaust. Restored after 25 years of sitting. Dyna elec coils, ignition. As old as I am, been in the family since new.
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- Limey
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Second thing to check for is vacuum leaks - make sure the carbs are into the holders (manifolds). That all vacuum tubes are connected and the balance tubes have good stoppers on them. Also check the manifolds themselves for cracks etc. At 25 years of no use they may be too brittle to seal properly and you may have to buy replacements.
Also check the mechanical sync of the carbs - again, the procedure should be in your manual.
Eric
Newmarket, England (for 3 years)
Pentwater, Michighan (Home)
1978 KZ650
2000 ZG1000
2006 Suzuki Burgman 650
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- bubbap
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1979 KZ650, Mac 4-2 exhaust. Restored after 25 years of sitting. Dyna elec coils, ignition. As old as I am, been in the family since new.
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- wiredgeorge
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From your blurb in your signature, this bike looks like it is a project. Have you checked valve clearances, tensioned the cam chain and how did you adjust the timing? Keep in mind I have no idea what your level of mechanical expertise is so any of things could be a stumbling block to getting the bike to run properly.
The reason I bring this up is that since you synchronized the carburetors and the bike won't run off choke, it makes me wonder about how some of the other things were done... not trying to be critical, just want to be of help. For instance, how did you check coil voltages? Let's get on the same page with some info... I have brought dozens of old bikes back from the grave and when I hit the starter the first time, I am pretty sure that the bike will start an run pretty much spot on. I bet we can get your bike running right if we back up and make sure the other stuff is okay before tearing into the carbs again (as you likely will need to).
wiredgeorge Motorcycle Carburetors
Mico TX
www.wgcarbs.com
Too many bikes to list!
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- bubbap
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1979 KZ650, Mac 4-2 exhaust. Restored after 25 years of sitting. Dyna elec coils, ignition. As old as I am, been in the family since new.
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- wiredgeorge
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I get nervous giving carb advice to someone who hasn't yet checked to see if the bike has oil in it. I think I have been guilty of this in past and I think we all jump to come up with answers where we would be better off analyzing the question a bit. You seem to have things under control as far as the mechanical stuff and ignition stuff so perhaps the carbs are the culprit.
The pilot circuit is still gummed up. If the bike will start on choke, it is running on the air/fuel mixture the choke (which is actually an enrichener) gives the bike at idle. You shut off the enrichener and the bike falls on its face. Is the bike driveable? This issue relates to the pilot (aka idle) circuit which affects things to about 1/8 throttle or a bit more. If the bike is driving, does it do the same thing in mid-range or have you not gotten that far. Anyway, I will be offline for a couple days and will likely get back on later this weekend hopefully. If you spray carb cleaner using the little straw they give you, does it come out the diffusion hole on the engine side venturi bottom? If it doesn't you need to keep cleaning. We use an ultrasonic specifically because these internal passageways are tough to clean.
wiredgeorge Motorcycle Carburetors
Mico TX
www.wgcarbs.com
Too many bikes to list!
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- bubbap
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Thanks,
1979 KZ650, Mac 4-2 exhaust. Restored after 25 years of sitting. Dyna elec coils, ignition. As old as I am, been in the family since new.
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- Patton
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Am wondering which is applicable in this instance, as the internal pilot circuit passages are different.
[Click on image for larger view]
1973 Z1
KZ900 LTD
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- bubbap
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1979 KZ650, Mac 4-2 exhaust. Restored after 25 years of sitting. Dyna elec coils, ignition. As old as I am, been in the family since new.
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- Patton
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79 KZ650's only have the side pilot air screw the bottom one, pilot mixture screw is not available. It is simply not bored out for there to be a screw just solid aluminum.
Hmmmm ...
In the diagram, #42 is a side-located pilot air screw shown in upper pic, and #30 is a bottom-located pilot mixture screw shown in lower pic.
Good Luck!
1973 Z1
KZ900 LTD
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