Bing throttle plate seating

The folks at Bing say the throttle plate should touch at 12 and 6, but I can't get it there for the life of me. Is there a trick to getting it seated correctly, or is it even that crucial considering there has to be some idle anyway?

do not tighten screws until lined up . might have to turn them around, rotate etc

Flip it around.

Make sure the disc is correctly oriented. It's got bevelled edges that should sit flat to the bore when the disc is closed. Supposedly it can go two ways (out of four possible) and only one is correct. I've never tried to see whether both ways work, but it seems logical they would.

Make sure the throttle stop screw has slack and it's not stopping the butterfly from closing.

And of course, the screws are loosened?

Oh, there are definitely some loose screws floating around.

Thanks for the tips, I'll give it another shot tonight.

My Bing throttle plates had a small dimple to mark the top (swb R75/5).

I don't worry about 12 and 6, I just futz with it until it is as close to perfectly sealing all the way around as possible, then tighten it up.

Hold it up backlit and you'll see light bleeding past the throttle plate.

Good tip on making sure the idle screw is backed off!! DAMHIK...

dc

I recently put new throttle plates, shafts, O-rings and screws on my R90/6. I have heard that of the 4 ways the plate fits only one is correct. My experience as of yesterday is that 2 ways fit. i.e. the only thing that maters is the bevel matching the bore and the plate is not drilled off center. Can somebody verify this? I can barely see the bevel, I can not see any difference top and bottom.

I cleaned up all the linkage parts good and also noticed it was of benefit to have the part that holds the shaft in on the carb before tightening the shaft screws and as mentioned the back off the idle screw or you are fighting against yourself.

Going to put carbs back on today I think.

Now that this has been moved to Airheads, Bump.

32mm plates should have a dot which goes up and out. 40mm plates have a '10' I think marked on them, which faces out but will be on the bottom.

Thanks Anton. I'll go look see if I can see a dot. I got them in already, seem to be a big improvement, one of the O-rings was compromised. Have not staked screws yet so can move if needed. Will stake eventually.

So I was able to remove carbs again the other day and checked for the Dot. Low and behold I had a small lightly stamped Dot on each plate and just by luck I'm sure I got it on the top outside edge. I didn't have Dots on my old throttle plates but those came from an after market source many, many years ago. these plates were from the dealer, they had Dots.