TOPIC:

I posted this on another forum and got no help there, its keeping me from riding, so someone please help!, by the way these carbs are off my 1980 kz750 LTD.
I took the carbs off, and I noticed that when the choke is pulled down, it pushes the slide, or as my repair manual calls it the throttle valve down, on only two of the cylinders, On the slides I noticed that there was a notch on them, that appears to be made to clear the choke butterflies. Two of the cylinders have the notch facing the choke butterflies, so the slides clear it and they do not move when the choke is on. The other two, do not have the notch facing the choke butterflies so when the choke is on it pushes the slide up on those two cylinders. Is this correct? it doesnt seem to me like it would be correct. Also where is a good place to buy rebuild kits. THis is the place that I was planning on buying them from.www.oldbikebarn.com/motorcycl...php?bike=KZ750

Also any tips when rebuilding them would be much appreciated

Post edited by: bigphil001, at: 2007/04/07 15:11

Post edited by: bigphil001, at: 2007/04/07 15:14

If I do this correctly there should be a diagram below.
When you say slide do you mean part #4 ? .. The slide with the black diaphragm on top ?

Yep there is a notch on the bottom and you know, in all the times I have taken them off I never noticed which way the notch faces. However, there is only one way to fit the slide. Take the top cover off the carb and gently pull out the slide. Examine the diaphragm for holes (holes are bad) and then refit the unit. There is only one way it will go back in. There is a little tab on the diaprhagm which fits into a matching slot on the carb..you can see in the diagram. If the slide are fitted the wrong way around or if holes in the diaphragm then the bike if it runs at all will run like crap.
From the parts diagram it would appear that the notch faces towards the air intake.

For rebuild kits try www.z1enterprises.com Most people here will swear by them.

When cleaning take them totally apart. I use 4 shot glasses labelled 1 - 4 for all the little bits. Poke nylon bristle from a brush through every hole you can find. USE SAFETY GLASSES and spray carb cleaner through every hole you can find. Blow compressed air through everything and reassemble everything.
Good luck.

I should have started the above reply by saying I assume your carbs are Keihin CV34...If they are the originals then they should be.

When cleaning the carbs there are a few more hole to check out. These are called the transition holes. To see then you need to open the throttle flaps on the engine side of the carb and take a peek in, In the roof you will find 3 tiny holes. With the flaps closed you cant see them. Get a fine pin or fine guitar wire, put a bend in the tip and poke the holes to make sure they are clear. If blocked you get crappy running at about 2,500 - 3,000 rpm. The photo below might help.

THanks I appreciate it a ton, I actually have the diagram that you showed me, and the membranes on the slide have the little notch to put them back in, its just the way that the choke valves were pushing the slides up just didn't seem to make sense to me, but then again I've never worked on this kind of carb before. Is it neccesary to drill out the plugs that cover the pilot jet, to clean the pilot jet? is drilling them out the best way to remove them or is there an easier way. Thanks again!

I wouldn't drill anything if I was you, especiallya well measured jet. Use a piece of fishing line or something plastic or plastic insulated to clean it, not anything that will scratch the jet

Actually on US models, the access hole to the pilot jet has a metal plug in it for emissions reasons, thats what I'm referring to you can actually see it in the diagram in this post, its number 28

Post edited by: bigphil001, at: 2007/04/07 21:22

O ok, good to go then, sorry

bigphil001 wrote:

Actually on US models, the access hole to the pilot jet has a metal plug in it for emissions reasons, thats what I'm referring to you can actually see it in the diagram in this post, its number 28<br><br>Post edited by: bigphil001, at: 2007/04/07 19:06

Thats the air mixture screw under #28 and I believe the only way to get that metal cap/plug off is to drill. ...not to far though..just enough to get through and then you should be able to lever it out. You should get a new screw washer and O ring in the rebuild kit.

The pilot jet is under part # 13 Teflon plug. The rebuild kit will also give you a new O ring for around the plug.

bigphil001
your initial question kept bothering me so I went out (snow gone) and took the pods off the carbs and had a look in.
All my carbs have notches on the slides and all the notches face back towards the air intakes. When I operate the choke flaps the flaps dont touch the slides - the notch gives clearance.

Your setup sound strange. I wonder if two of your slides were replaced with parts from a different model ?

Sorry it took until now to check this out.

The carburetors were disassembled and not reassembled properly. The thing with a cap that is on the engine side/top is the pilot mixture screw. It is right under the blank cap. The cap was put there to keep folks from adjusting idle mixture but over time, the screw needs service. Take care as that screw galls to the well it sits in and can stick and if it does, the head will strip easily.

Thanks I drilled those out and cleaned them and returned them to the factory setting, could someoen explain to me how to adjust the screws after I have the bike running?

Yeah I just discovered that the last guy butchered the carbs, he kind of made his own synchronizing screws, drilled out the stock ones and fitted his own, which look to be really hard to get synchronized, and one of the throttle valves has a giant chip in it, so if anyone out there has those parts, or a used carb they want to get rid of for cheap please let me know!