Vacuum sync

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barbos
Posts: 297
Joined: Tue Nov 18, 2008 7:22 pm
Location: TN

Vacuum sync

Postby barbos » Thu Dec 15, 2011 8:25 pm

I did a valve adjustment and decided to check the vacuum sync while it was apart. When I have both the bikes computer hooked up, and my vacuum sync tool hooked up (like demonstrated in the service manual), Cylinder 1 is very weak. I'm unable to adjust them to be balanced.

If I plug the vacuum line going to the bike's computer, they are in sync. It would make sense that having two lines coming out of one cylinder would cause it to be weaker, but I the manual seems to illustrate that this is how it is tested.

I sync'd it with just the two lines going to my sync tool and have been running with it like this for a week. I'm not convinced this is correct.

Would appreciate any input you guys have.
electjohn
Posts: 310
Joined: Sun Oct 12, 2008 4:38 pm
Location: North East Ohio

Re: Vacuum sync

Postby electjohn » Fri Dec 16, 2011 6:17 am

I know this will cause a lot of disagreement but I am not a believer in going to great effort in syncing the throttle bodies. IN my race motors that are not motorcycle motors I mechanically set the opening on the carbs or throttle bodies. Once off idle it doesn't matter and with the camshafts we use the idle isn't stable. Used a vac. guage once and didn't see any diff.
barbos
Posts: 297
Joined: Tue Nov 18, 2008 7:22 pm
Location: TN

Re: Vacuum sync

Postby barbos » Tue Dec 20, 2011 2:28 pm

Well, I wasn't really asking about the merits of doing a sync, but more of the proper way to do it. I'm guessing it not right as my gas mileage is noticeably down, the bike is more sluggish, and the exhaust is farting more than normal.

The only positive note is it has a bit of a growl to it now which sounds cool, but it isn't running as well as it should.
steigs84
Posts: 117
Joined: Thu Oct 02, 2008 2:17 am
Location: Fort Worth, TX

Re: Vacuum sync

Postby steigs84 » Tue Dec 20, 2011 8:09 pm

According to the Manual (and my bike, 2006), one vacuum line goes to the inlet air pressure sensor, then you have two vacuum plugs.
The plugs you pull to hook up you sync tool.
The vacuum line to the pressure sensor (which I am assuming you meant the one to the computer, as the computer has no vacuum lines going to itself) should not be removed for any reason while performing the sync.
If #1 and #2 are not in sync and you can't get them close, then as the manual said, remove #1 sync screw, washer and o-ring, look for carbon, clean if necessary (which was the problem with mine on both screws), inspect seat in the throttle body for carbon and clean if necessary (again, mine was plugged) reinstall. after your check one cylinder, the manual tells you to sync again. Then to start this procedure with #2. Carbon build up could also explain the weak vacuum signal from #1
My advice, pull the throttle, clean inspect both screws and the seating area of screws and throttle body, re-assemble and try again. When you seat the screws after cleaning them, just turn them enough to seat.

Many people have found the problem to a missing vacuum plug, broken hose or misrouted hose.
barbos
Posts: 297
Joined: Tue Nov 18, 2008 7:22 pm
Location: TN

Re: Vacuum sync

Postby barbos » Wed Dec 21, 2011 4:14 pm

Screw/spring/o-ring were in great shape when I checked them. Will dig further. Thanks
barbos
Posts: 297
Joined: Tue Nov 18, 2008 7:22 pm
Location: TN

Re: Vacuum sync

Postby barbos » Mon Jan 09, 2012 12:16 pm

First attempt at valves, I went with what felt like a slight drag and used that as the measurement. I did it again this weekend and went with the largest feeler gauge I could manage to cram into the space. Ended up tightening all of them up. Vacuum is strong and in sync, and the bike pulls like never before.

:grin:
steigs84
Posts: 117
Joined: Thu Oct 02, 2008 2:17 am
Location: Fort Worth, TX

Re: Vacuum sync

Postby steigs84 » Mon Jan 09, 2012 11:57 pm

Glad to hear that.
howie333
Posts: 12
Joined: Fri Mar 13, 2009 5:38 pm

Re: Vacuum sync

Postby howie333 » Tue Jan 17, 2012 12:24 am

07 650R
I just got done w/ my 2nd valve check, and I'm in process of inspection of syncing the throttle bodies, even though the motor runs fairly well. I have a digital tach-meter w/ mag pick-up, and an old Motion Pro mercury sync tool. lost mercury, but could buy replacement non-mercury fluid. The only problem w/ this tool is you cant check standard vacuum, as is noted in the manual as a reference of vacuum. Not sure if that's important. I've been considering the recomended Harmonizer sync balancer with built-in tach, seems the way to go w/ checking and adjusting sync balance. Any experience
w/ balancing w/ either or both these of these units?
Please reply,
Howie/ balancing /...
barbos
Posts: 297
Joined: Tue Nov 18, 2008 7:22 pm
Location: TN

Re: Vacuum sync

Postby barbos » Tue Jan 17, 2012 5:48 am

I balanced mine with a harmonizer. Couldn't really use it for a tach, but the balancing and vacuum modes seemed to work fine.
howie333
Posts: 12
Joined: Fri Mar 13, 2009 5:38 pm

Re: Vacuum sync

Postby howie333 » Tue Jan 17, 2012 8:49 am

barbos wrote:I balanced mine with a harmonizer. Couldn't really use it for a tach, but the balancing and vacuum modes seemed to work fine.


I've read the Harmonizer Tach works on vacuum pulses. instead of my 13yr old hand held version, I could always pick up a new unit for ~$65, but not sure if it'll work w/stick coils. I could allways buy a single vac guage to set standard vac, then use my mercury motion pro vac guage for sync.
Howie...
barbos
Posts: 297
Joined: Tue Nov 18, 2008 7:22 pm
Location: TN

Re: Vacuum sync

Postby barbos » Tue Jan 17, 2012 9:29 am

Yea, it works on vacuum pulses. It seemed suggested that it is probably not accurate but more of a guide. The tach numbers seemed erratic for me, but maybe I wasn't doing something right. I just wanted to balance it.
howie333
Posts: 12
Joined: Fri Mar 13, 2009 5:38 pm

Re: Vacuum sync

Postby howie333 » Tue Jan 17, 2012 12:55 pm

barbos wrote:Yea, it works on vacuum pulses. It seemed suggested that it is probably not accurate but more of a guide. The tach numbers seemed erratic for me, but maybe I wasn't doing something right. I just wanted to balance it.



Thanks for reply;
Still not sure if reading standard vacuum is important sa. manual listed specs, and if so; I could then use the mercury manometer.
Howie...

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