SVS140 wrote: ↑Sun Apr 21, 2024 1:59 am
navigator wrote: ↑Sat Apr 20, 2024 11:21 am
Start by introducing plenty of slack at the adjuster at the grip.
perform your sync, then when done, adjust at the grip until you have 1/8" of play before the throttle engages.
Hi Navigator.
I tried this out - admittedly, I don't have much slack at the grip as I was already near the limit - could this be related
![I don't get it :confused:](./images/smilies/icon_confused.gif)
I did turn it a couple of turns though and it feels a bit more slack.....
However the problem persists. I could raise the rear cylinder (left gauge) vacuum as high as the image below however it was running at around 1300rpm at that point.
Another question I have, is it expected to move down that arm on top of the idle screw by hand rather than turning the idle screw out? I can turn the screw in and it pushes the arm up increasing the idling speed but when I hit the 1300rpm with the sync cable adjustment, I can't turn out the idle screw as the arm stays up and I have to manually push it back down and lose all sync settings in the process.
In the image below, you can see the idle screw turned down but the arm does not retract down with it - is this normal??
Thanks in advance for any help.
It appears to be a mechanical issue.
Since it appears there is no slack in the cable above the adjuster in your 2nd picture, that cable is holding the throttle open. The return spring on the butterfly of the rear carb should be strong enough to close the throttle. if you can close it by hand, something is hung up.
Get as much slack at the grip as you can, to be sure the grip is not opening the butterflies.
Check your cables to be sure they operate freely. The cable splitter under the tank is another place to check for problems.
In a static position, each carbs butterfly linkage should snap back to the closed position with the aid of the return springs.
If all that checks out, start by adjusting the cables so that each carbs linkage starts to open at exactly the same time.
The carb sync adjustments are very finite, a small turn goes a long way.
The idea is not to get as high a vacuum as possible, but to have the vacuum equal on both carbs.