Keihin cv34 carbs

I have my keihin cv34 carbs out of my 82 kz750. At this point Im seeking some direction. The carbs have been altered to run with a kerker exhaust. I took that off and put original pipes on. THe bike barely runs and only with the choke fully on which doesnt make sense because the stock pipes should have more back pressure and cause the bike to run rich.

I assumed the jets were changed but they are the stock jets. (main 62 secondary 125).

I found that one of the mixture screws was missing its point. Does anyone know where I can get parts? Also one of my needles is bent so I need to replace that also. I think this is a good start.

Any help would be apprecciated. THankyou

Once you get the jets and screws sorted out, make sure you clean the pilot circuit til it's clean. Then clean it again. If I remember correctly there are three holes right at the edge of the butterfly and another hole further down the throat. Make sure they are all clear. The plastic plug that sits over the top of the pilot jet (I think it's called pilot) needs to fit snugly. Mine did not and it let in way way too much fuel. Also treat your slide rubbers like they are gold - they can be $$.

Once you get the, clean and lined out they are nice carbs. My 1980 750 ran like a complete dream once I got the carbs lined out. Miss that bike....

Also just because they are labeled w the stock # doesn't mean the previous owner didn't drill them out.

I completely went through two sets of those carbs. Kind of a pain in the butt because you need to remove the choke butterfly linkage in order to ungang them. After you got them separated then you can do a proper carb dip on all the parts to assure all the internal passages are clean. Z1 Enterprises sells all the various O-rings and replacing these 35 year old rubber parts is critical for proper running and keeping the fuel inside. K&L sells packs of float needles and I recommend you replace the stockers straight away. I don't normally like to replace the stock internal parts but as the float needle springs get weak the fuel level goes up in the carb and I found that model carb tends to overflow so they need all the help they can get.

Regarding the broken pilot screws, you might want to carefully check the carb body to make sure the tip isn't lodged inside the carb passage. No fuel will flow through that orifice if it is blocked.

Ok thank you for the comments. I will let you know how I make out.

I decided to rebuild just about everything. I rounded up all of the parts except the needle. I cant seem to find it anywhere without buying the entire assembly. Any suggestions? Otherwise Ill just try to straighten the old one.

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At this point the bike is idoling perfectly but when I crack the throttle it boggs down at high rpm. The screws are adjusted to 3 and a half turns. The plugs are showing that it is running lean but it I adjust the screws out anymore then it wont idol and dies. At this point everything is fresh and stock so I'm not sure where to go from here.

Do you still have the stock airbox installed?

A useful gizmo a friend gave me is an o2 hand held sensor. The kind they use in a Dyno shop. They're really useful for measuring exhaust gas. The example I have is not calibrated properly but still gives a fairly accurate analysis of AFR. It's been invaluable when editing maps and on my carb bikes. Not sure which retail outlet you can get them from but they're well worth the investment IMO