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
