stock jets of keihin cv34

What are the stock sizes of keihin cv34 carbs? Found 125, 63, 65. Don't know which is which but the numbers are as above. Also should it be written somewhere on a carbs "cv34" because I found some numbers but not "cv34". The thing is that when I unscrew mixture screw 2 turns out its hard to start if unscrew 3 turns it sturts but bangs from exhaust. So that is why I checked cor jets because I thought jets might be changed by PO. It is not normal I guess that I need to unscrew 6 turns out so bike starts and idles fine? Carbs are cleaned. What else I should check in carbs?

I seem to remember we had some discussion in an earlier post regarding the description "83 750E" so i am hoping to avoid any confusion here. The 80, 81 and 82s were E1, E2 and E3 models and came with the Keihin CV34 carbs. The 83s were different and came with Mikuni BS34s. I see that you are in Lithuania so accept that things may be different there.
Patton posted this earlier and it might help



The Keihin logo should be on the carb but you wont find "CV34" anywhere.
If your carbs are like mine then the stock jetting should be Primary main 62 and secondary main 125. see photo



I found out recently that there was another Keihin CV34 carb on some of these 750s that didn't have a primary main.
6 turns out on the screws is huge.

If things are not working correctly with the screws in the region of 1 - 3 turns out then there are only 2 reasons I can think of.
One is the service fuel level in the float bowl is off, This should be at (I think) 4 +/1 mm below the seam between bowl and carb body. I found that eyeballing the level is not not good enough and the level has to be measured. Search for "clear tube method". Patton has posted some great diagrams for this procedure. Getting the levels correct was the single biggest improvement I made to bike running when I got it first.
The second reason might be the screws themselves. If not already done I would suggest removing the screws along with the springs washer and O rings and check and clean everything. The washers and O rings are tiny and I have heard that worn or missing O rings and washers can cause problems.
After all this a carb synch would probably be a good idea.
Hope this helps
Good luck

The frame number is KZ750E-037315 so I guess it is 82' KZ750E-L2? I checked the pilot screw, o-ring and washer and everything seems to be fine. I will check float level tomorrow.

From the info I have been able to find and make some sense of here are the carbs on which model/year

1980 E1 and H1
Keihin cv34

1981 E2, H2 L1
Keihin CV34

1982 E3, L2, H3
Keihin CV34
1982 R1
Mikuni BS34

1983 L3
Keihin CV34
1983 H4
Mikuni BS34
1983 ZX 750 A1
Mikuni BS34

1984 Kz700 A1 kz750L4 ZX750 A2
mikuni BS34

1985-1988 ZX750 A3 - A5
Mikuni BS34

So I checked floats height at rest is 18.5mm and the floats holds against carbs body (height couldn't be smaller). How do I measure this 4-5mm?

Hi
Float height is no good.
You need to measure the fuel level in the bowls.
Click here kzrider.com/forum/2-engine/532282-one-cy...r-isnt-firing#532558 and scroll down to Pattons post with the diagrams. Your carbs will be slightly different from his example but the idea is the same. His example shows 3 mm but I just checked the 750/4 manual for the CV34 carbs and the specification is 4 +/-1 mm.
To get the exact measurement you can either mark the clear tube or hold a ruler beside it. If you find that you need to increase the the fuel level by say 2mm then you will need to adjust the float height by 2mm in the right direction. There are lots of post here on fuel level and clear tube method
Good luck

Thank you guys for the help. So I measured fuel level and it is 8mm from matting surface. And you said it should be 4-5mm. Should I target for 4mm or 5mm? So 8-4(or5)=4 or 3. And then 18.5+4(or 3)=that is how much should I bent to get correct fuel level? By the way which part exactly I should bent?

OK
If your fuel level is 8mm below the bowl/ body seam then it is 4mm to low. So you need to adjust the floats to increase the fuel level by 4mm. You should target a final level of 4mm. You will need to remove the carbs from the bike. turn them upside down and remove the bowls. First check that the float are not upside down. I have made this mistake myself and it screws things up

In the picture below, the red arrow points to the shiny metal part - which we call a tang - which presses on top of the float valve causing the fuel to shut off. This is the part which you bend to adjust the float height,




I used to use trial and error but then read a post here by Tek9ine an find the following method great

The picture below shows my carbs. The ruler shows a float height of 24mm. If my fuel level was 8mm and i needed it to be 4 then I would bend the tang until the float height was 20mm. This would raise the fuel level by 4mm to 4mm. below the bowl/body seam
I had to think about how best to explain and I hope it makes sense



Just realised I had typo above. Fuel level spec is 4 + or - 1 mm sorry

Am I doing something wrong because nothing happens if I bend tang up or down except when I took to extreme it overflows. I put carbs on the bike connected tube and open fuel tank flap and the level is way too low. Is it any different if I route the tube to the front or to the side of the carbs body? And how do you know how much to be bend because it seems it won't matter if I bend up or down floats when at rest gives same hight and holds against carb body. It is because of the needle which has moving pin?

Must be something wrong.
I "borrowed" the picture below from the Z1Enterprise site, It shows a float from a 750 twin and the tang is circled in red, Your floats will not be identical but the idea is the same. In normal circumstances with the carbs upside down on the bench like in the picture in my post above the tang rests on the pin at the end of the float valve and if you bend it one way you raise the float height and bend it the other way you lower the float height. If bending even a tiny bit does not change the float height then something is seriously out of place. Check the operation, check if the floats are upside down or catching the side of the carb

I took the picture of the floats at rest position:

From what I saw on the internet and manual floats ar not upside down. By the way when bending tang and measuring height should it compress the fuel level valve spring because of the weight or should I put carbs in that position which won't compress but just touches? I read different opinions on the net.

Clear tube test is supposed to draw fuel from the float bowl drain, and NOT from the overflow circuit.

If not already done, may need to loosen (not remove) the float bowl drain screw while performing the clear tube test. Otherwise, fuel from the bowl nipple is from the overflow circuit (which is incorrect for the clear tube test).

Good Fortune!