TB synch

QSIMDO · Post by **QSIMDO** » Sun Sep 11, 2005 3:54 pm

Reading the posts here about excess vibration I recognized some familiar symptoms so after today's ride I tossed on the Merc stick.

My right side TB is about 2.5 lines higher than the left.

So what's the drill for synching the '04 R?
Drop the high side? Raise the low side?

Do I assume correctly the adjustment is made with the cable adjusters?

This is only my second FI bike and I'm in a fog.

TIA!

Post by **arkline** » Sun Sep 11, 2005 4:28 pm

In the current issue of the BMWON there is a great article on TB syncing using the Twin Max. If you can borrow a copy from someone nearby you could easily adapt the process for use with mercury stix. It isn't complicated, but does require patience and accuracy. Great pictures with the article, by the way.

Post by **mcooperstein** » Sun Sep 11, 2005 5:18 pm

I read the article on TB sync in latest issue of BMWON and don't particularly like it. Mind you, I'm no expert, but I have learned to do one thing on my bike well, and thats do a throttle body sync! I use the TwinMax, which is what the article focuses on so if you're using carb stix it wont help much.

What I didnt like about the article was that I believe it to be technically in error when discussing the procedure for setup on the TwinMax. The author goes through the steps for 'zeroing' the meter movement in detail, but then neglects to mention that with low sensitivity you will NOT get enough meter deflection to see the vacuum (sp?) differential between the two throttle bodies. IOW, after zeroing the meter and then starting the engine its necessary to increase the sensitivity to maximum to see the desired effects. This little omission irked me, as what good is a technical article that is 'technically incorrect?'

Also, the author neglected to explain exactly what is happening when you are measuring needle deflection on the TwinMax. You don't have to go into any great detail here, but a sentence or two explaining the difference between a pressure differential device such as TwinMax and a manometer (carb stix) might have been in order. It always helps to know why your doing what your doing!

There are several good documents on http://www.ibmwr.org, "The Internet BMW Riders" website that show how to do a tb sync using either a TwinMax or carb stix. Carb stix work real good too, the end result is the same, but you (obviously) use a different approach then an electronic meter such as a TwinMax.

Oh, and to answer your question...the low rpm sync is achieved by adjusting the big brass screw on either throttle body. The high rpm (3K rpm) sync is done by adjusting the throttle cables themselves.

Mark

QSIMDO · Post by **QSIMDO** » Sun Sep 11, 2005 7:34 pm

Excellent!
Thank you.

QSIMDO · Post by **QSIMDO** » Tue Sep 13, 2005 8:01 pm

TB Synch redux;

Today I received a Clymer manual covering '93-'04 R850, 1100, 1150 and 1200C models.

Page 94 addresses TB synch, "All models except R850C, all R1150 and R1200C" and the proceeds to describe the procedure.

Page 95 addresses "R850C, all R1150 and R1200C models" and the entry reads;

"There is no synchronization procedure on these models. This service must be performed by a BMW dealership using the MoDiTec diagnostic tool."

So...WTF and who's zoomin' who?

Post by **mcooperstein** » Tue Sep 13, 2005 10:03 pm

obviously BS

Post by **CycleRob** » Tue Sep 13, 2005 10:13 pm

WTF and who's zoomin' who?

They're not zoomin' you, they're just confused with the facts. You can do the synch yourself -but- you must not touch the blue painted screws on the TPS mounting AND the throttle stop screw/locknut on the left TB.

As for instructionals, I do NOT recommend IBMWR.ORG for help as the 3 that I just read there have too many errors of omission that will get you in trouble. What kind of errors?

--They have you loosen cable locknuts without even checking if the setting is perfect to begin with - - it usually is.

--They have you tighten the cable locknut without checking the synch afterward - - - it can/will change after tightening.

--They have you counting BBAS turns to seated. This step is unnecessary to get them even unless the bike has a zillion miles on it. This might also matter IF you have the understanding to adjust the blue painted screw on ONLY the RIGHT side TB to even up the butterfly openings.

--They say "tighten the locknut" but fail to warn you to be gentle with the musclepower so you don't strip the threads on very soft, expensive to replace throttle cable fittings.

The absolute best instructional I've seen is from the ADVRider guys. It spoon feeds a novice with caution, humor, pictures and most importantly, highly detailed correct information. To download the.PDF file, Go here:
http://advwisdom.hogranch.com/Wisdom/TBS4Dv1.0.pdf

Post by **geechie** » Wed Sep 14, 2005 9:06 am

I performed what was probably my most accurate TB synch to date this past weekend. The final nudge of the locknut brought both columns into absolutely perfect agreement. And now, thanks to Miss Ophelia finally moving on, I was able to ride in this morning. The bike, which wasn't all that bad before, is butter smooth this morning.

I love getting to work with that, "I'm king of the world!" feeling.

George