Topic: More 750 carbs

[DaveInTexas]

I am still working on them, they are squeaky clean now and I have new Orings to stop the leak I had on the T fitting to the supply line. 

I recorded all the settings in case I needed them and wanted to run them past you guys to see what you thought.
The throttle stop screws were set anywhere from 2 to 4 turns out.  I have reset them to the book suggestion of "until the T on the shaft is fully exposed'. 
I gather this is how you adjust the bike's engine idle speed.  I'd imagine we want them all set to the same place.

The low speed air screws are all still set to one full turn out.

Do I have this right, the needle attached to the throttle slide (cylinder) sets the high speed mixture, by adjusting where it is attached to the slide.  (further down = leaner mixture).

Sorry for the deluge of questions, internet was down for several days, I saved em all up for ya!

[Bob Wessner]

From my own experience, these are correct, but consider them starting points. You may, as you sync the carbs, do plug readings, if you plan to, have to make some minor adjustments, but this should get it running all else being equal.

the needle attached to the throttle slide (cylinder) sets the high speed mixture, by adjusting where it is attached to the slide.

By this, I'm assuming you mean what postion the clip is in on the needle. Stock starting position should be the middle position, again, should get it running and based on plug readings, you may have to change slightly depending. Are you using stock exhausts and stock airbox? The middle clip position worked fine on my K0, even for the one pipe replaced with a 314.

[DaveInTexas]

Thanks Bob-
Yes; all is stock as far as I can see (and know about it, and have been told about it)!

I went out and attached the slides to each carb with the settings all the same on the throttle stops - the book 'T' position.
Then I cycled the throttle grip several times and looked into the throats.  I could see that all the slides were coming to a different position, some were open wider than others.

So I decided to get scientific about it  -ha-  and used my set of drill bits to measure the distance from the floor of the throat to the bottom of the slide where it has a curve (a pic would help?  I'm just measuring how open the throat is on each)

They were all different, some would not accept a 3/32" bit, others would accept a 1/8" bit.
SO, splitting the difference, I decided to set them all to where it would just accept a 7/64" bit.  Now they all stop at the same position and with the same throat opening.  Hopefully they will all now get the same amount of air at idle! 

What do you think? 


Number of turns out, throttle screw to achieve a 7/64" opening:
Cylinder   Turns of screw
...1................3.0
...2................5.4
...3................3.6
...4................4.5

I figure they are sooo different because of age.  The slide or the screws have worn over 37 years.