High Vacuum while performing sync

[jeddi03]

I have the motion pro carb sync tool. Previously when I have synced the carbs, the fluid would only be about 1/4 of the way up the tubes. I leaned up the carbs a quarter turn and now the fluid is practically to the top of the tubes, and I have never seen that much vacuum while syncing.

Any ideas on why there is so much vacuum? Is it due to leaning the mixture a little bit?

Thanks for the help!!!

[arsenic]

what RPM's was the bike at when you tried to sync them?

[jeddi03]

approx 1800

i could get it to sync, just at an oddly high vacuum

[arsenic]

ok, then I have no idea.

[jeddi03]

The only thing that I haven't done is put in the new air filter. Would a dirty filter cause this? I mean it does not appear to be dirty, but I dunno either.

[squiggy]

Is the restrictor rubber/plastic plugs, one per hose, still in the hoses or did they fall out? They should not have fallen out since they are, at least on mine, a tight fit.

Mine are white in color.

[jeddi03]

I have brass ones but they are still there.

[squiggy]

I have brass ones but they are still there.

hmmmm...

[jeddi03]

could my carb floats be too low? would this cause excessive vacuum? I'm just trying to think if every possible thing that could cause this?

They are set to 13mm. Dunno just getting as much info out there.

[arsenic]

no. The ONLY thing that will cause high vac. is a high RPM. Your float heights, jetting, etc, etc. That's matters not.

[JayBell]

just use the screw adjustment on each tube reservoir to lower the fluid levels on all the tubes

done.

[The CyberPoet]

I have the motion pro carb sync tool.

The only thing that I haven't done is put in the new air filter. Would a dirty filter cause this?

If by dirty, you mean somewhat soaked with fluid or really clogged, it might. Swap filters to check.

Normally, rich engines (say you've installed the Ivan's JetKit for example) will generate a bit more vacuum than the OEM jetting -- a big part of the reason for the throttle-responsiveness is the extra vacuum that a richer mixture provides. BUT it wouldn't normally be enough to push the Morgan-brand gauges from down in the typical 1/4-range to the 3/4+ range. You did have the gauges standing upright, correct? The morgan does rely on gravity as part of the effect of the resistance of the slugs. No clue about the MotionPro type ??!?

Not that's it particularly relevant -- as long as if you swap hoses between the carbs (or between the ports on the SyncTool) and get the same basic readings, you know the sync is valid.

Cheers,
=-= The CyberPoet

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[squiggy]

just use the screw adjustment on each tube reservoir to lower the fluid levels on all the tubes

done.

From what I remember there are none for the Motion Pro mercury kind.

[jeddi03]

the fluid screws are as far out as possible to make them even when calibrating the unit.

I do have the ivan's kit, but i have had that from day one. the carbtune was straight up and down.

I know that my sync was valid, just found it strange that the vacuum was so high.

If by dirty, you mean somewhat soaked with fluid or really clogged, it might. Swap filters to check.

Normally, rich engines (say you've installed the Ivan's JetKit for example) will generate a bit more vacuum than the OEM jetting -- a big part of the reason for the throttle-responsiveness is the extra vacuum that a richer mixture provides. BUT it wouldn't normally be enough to push the Morgan-brand gauges from down in the typical 1/4-range to the 3/4+ range. You did have the gauges standing upright, correct? The morgan does rely on gravity as part of the effect of the resistance of the slugs. No clue about the MotionPro type ??!?

Not that's it particularly relevant -- as long as if you swap hoses between the carbs (or between the ports on the SyncTool) and get the same basic readings, you know the sync is valid.

Cheers,
=-= The CyberPoet

[hardlydangerous]

turn down the idle to 1200 rpm

if that don't help
try it without the air filter

fluid type don't need the engine running at high rpms to sync