Need some advice
 

Finally got around to syncing the TBs on my bike. After I found the easy way to disconnect the fuel pump electrical, and got the little bastard air screws loose without destroying them, I found that there's no way in hell to adjust them with the airbox on. So I had to remove the airbox sensor and let it hang out so the FI light would stay off.

Here's the screwy part: Those air bleed screws don't seem to change the vacuum reading. It bounces between 20-30mm/Hg and I'm trying to set it to 26.5mm +/- .5mm at 1350RPM +/- 50RPM. I can wind one all the way out, and all the way back in and not notice anything different. Of course, it's been 33k miles, and you're "supposed to" check them every 7500. Any ideas?

I'm not familiar with the 650R and I've only synced my bike which has carbs and is an inline 4 so this is very general. On my bike there were a few screws all in the same area as each of the synchronizing screws. It may sound basic but just make sure you are turning the right screw. Also on my bike I would have to make a small adjustment then rev the engine up to 3-4k rpms then go back to idle before it would show a difference on the vacuum gauges (motion pro mercury filled vacuum gauges). If I made even large adjustments it wouldn't show much until I reved it. If you do this rev it SLOWLY up and down. Abrupt changes in the throttle can create a strong vacuum that can suck the mercury out of gauges like mine and in to the engine. Good luck.

The air mix screws aren't for adjusting the vac. balance. That's accomplished by adjusting a screw @ the linkage which varies the butterfly position of one carb relative to the other (typically right at the throttle cable bellcrank) - very easy on a twin. You'll need to get the vac balance adjusted & then adjust the idle air mix since it's wonked-up now - procedure should be in the service manual.

EFI guys.

I have a pair of round gauges- no mercury. They definitely show a strong vac change when I twist the throttle. I'm thinking a mercury gauge might read more steady.

All I have is two air bleed screws. As far as I can tell, the throttle plates (both Computer controlled and Manual) are a single shaft between the two bores with no adjustment. Turning out the bleed screws, I can hear hissing, but I wonder if they need pulled and cleaned (after 33,000 miles I suppose that shouldn't be a surprise). I think both screws were full shut... but can't tell because it took some work to get them moving. I turned them both full shut, then out a quarter turn and put everything back together.

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