Setting up carbs

[Duffy]

Could any one help in advising me with what the initial set up for the butterfly valves are please.

[Duffy]

Sorry forgot to add for 1979 kz750b

[Michael]

Hi Duffy,

the butterfly valves are set via idle screw and probably needs adjustment via carb synchronisation.

Initial setup is both butterfly valves at same height (synced) and a little bit open.

Do you have the carbs removed from the engine ?
Then you may hold them against a (strong) light and you should clearly see a “slim half moon” at the bottom side of these valves.
Good chance the bike will start, when carb and it’s idle system is clean and fresh fuel is in the tank 😉

Cheers, Michael

[Duffy]

Thanks Michael, I will post picture showing butterflies before adjustment, balance screw was missing which wasn’t helpful!! Carbs back on, and running better. Now my back wheel bearing gone aaaaah!

[Michael]

Hi Duffy,

balance screw / sync screw is definitely needed !
Otherwise the butterfly valves have no chance to work synced.
Without that screw you can’t even set idle speed correctly.
Not to talk about idle mixture screw.
Engine will be running like “shaking a pot of screws!”
As we say: “Läuft wie ein Sack Nüsse!”, which means the same thing 😉

How did you solve it, can’t see that on the pics ?

To bad with the rear wheel bearings !
There is a spacer tube in between the two wheel bearings. Don’t press the new bearings to strong against this. With new bearings in final position you should be able to move this spacer tube with a screw driver or even your finger a little bit up and down.
It is bad when this tube is completely loose and you can “rattle” it, but it is worse if it is totally fixed by the bearings.

Good luck,
Michael

[Duffy]

Hi Michael,

Thank you for sharing your knowledge it is appreciated.

You asked how I solved the carbs, well thank goodness for my brother!! He found a replacement screw and has made the adjustments. He has made temporary repairs to split engine breather and inlet from air box to carb. I don’t know how well your English is but it would be described as bodged here. I have garden hose with copper pipe bend from the crank and some two pack black stuff filling any holes in inlet hose!! All can be sorted later but thanks to him she is running.

Trudie

[Michael]

Hi Trudie,

for “bodged” I need a dictionary to be honest.
Now I understand 😉

Good to know your bike is running again.
That’s what it’s all about 😉

Cheers, Michael

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