Topic: K0 needle position Q?

[Don R]

Stock 750 K0 except for a hooker 4 into 2 with baffles. 40 pilots and 120 mains as new.  The needle clips are on the next to lowest position making the needles higher and richer. Marks book says they came in the middle and then a bulletin required them one notch higher, Leaning the midrange.
 The question is, back to the factory position or leave them because of the header? The guy that worked on it was pretty good but we usually over reacted to a change back then.
 The slides are out now so a change would take a couple minutes, I'd like to get it right once though. I'll move on to the headlight until we decide.

[Johnie]

Don...mine are in the middle position and have always been there. Good looking plugs at the end of the year. Pretty much just followed the manual on the KO. Not really sure what the 4-2 would do, but they are easy enough to change out if you want to change it back later.

[lucky]

I would leave the needles in the stock position. LUCKY


You are very fortunate to have those carbs. They were the best ones.

BTW see some of my posts about adjustment of the throttle cables.

[Don R]

Back to stock it is. I was afraid of the metal clips, as in breaking one but they seem to come out OK.
 Thanks Lucky, I will check the cable adjusting thread.

[Don R]

Lucky, any hints where to look? I can't seem to search the correct terms.

[70CB750]

I did test ride all positions, it was very educational.  Mine are number 4 notch on the needle, counted from the top. 

I don't have stock airbox or stock exhaust and with needles like this, it has more power than I dare to use.

[lucky]

Lucky, any hints where to look? I can't seem to search the correct terms.

Ok..I will just put it here again.

When you install the throttle cable inspect it of course.
Then you will notice two of the cables going from the splitter tube/box are shorter.
Those two cables go in the center.
On the adjuster on the cable up by the handlebar take out all of the slack.
And this is important: DO NOT tie the throttle cable down. None of it.
Like no cable ties on it except one very loose one after the gas tanks is on.

Make sure the splitter box is centered. On top of the engine.

Get all 4 cables adjusted by using the adjuster on top of the carbs, turn the throttle and make sure that as soon as you start to turn the throttle that the slide starts to move. You can put your finger into the intake and feel when the slide is starting to move.

Put all of the mixture screws at exactly one turn out.

Put all of the idle screws on the "T" mark and make sure they are not lifting the slide at all. On these carbs when you turn the idle screw INWARDS it actually raises the slide. So do not use them because you will have nothing but problems. It will then be out of sync. Just use the adjuster up by the handlebar to raise and lower the idle.

Do not turn those mixture screws when syncing the carbs.

Sync the carbs and use the adjusters on top of the carbs.
If you have to raise the idle USE the adjuster up by the throttle NOT the idle screws!
IF you use the idle screws then the sync will be off again.

Should idle about 1100 RPM.

IF you are getting any popping at idle on decell then open the mixture screws 1/8 turn.
Usually on these bikes with these carbs the mixture screws can be set at 7/8 turn out. But when you are setting this all up just open them to 1 full turn out.
Forget that lean best idle . That just gets the sync all off.


Remember the sync is getting all 4 slides to open at the same time.

You should only have to raise a slide about .007 thousandths to get the sync right.
Don't worry about the fact that some adjusters on top of the carbs are not equal height.

Notice in the photo below the position of the splitter box.

[Don R]

Thanks again lucky. My 70 came with the outboard cables under the frame. They were kinked pretty hard just above the carb. I took lots of pics before I moved anything on the sandcast, my splitter was right there too.

[Johnie]

Nice right up there Lucky. Is that in the carb Q&A area? Should be if not...
I was told on this board these KO carbs should be synced at 3,000 RPM and then do the slow idle last.