Throttle Body Sync - Looking for your thoughts

[2 Wheel Wanderer]

Just curious to hear your thoughts on which RPM to set it at and why. Ducati manual says run slightly fast and Brad Blacks write up says sync between 4-6K. There is a vacuum difference between the two, at the higher RPM the horizontal leads the way.

Background on my bike, 05 M620 Open airbox w/ DP chip and Termis. Had valve guides replaced, 6K later I had to get the exhaust guide replaced again. Bike is back together and tuned but there is still a bit of vibration I can feel in the pegs while riding. Just trying to smooth it all out.

Thanks all...

[Howie]

IMO,if there is a big difference between idle and at speed, something is wrong, like idle air pass out of adjustment on FI or idle mixture on a carbie.  Beyond that, it is more preference.  Me, I would do a compromise if needed.  A track guy would probably want to synch at speed.

[2 Wheel Wanderer]

Not a big difference but enough that it's buggin me. If I sync at 2-2.5K then rev up to 5K the horizontal cylinder starts to take over. Friday I'll just sync the TB's at the higher rpm per Brad and it'll probably smooth out. I tend to beat the crap out of my bike and hold it at the higher end of the rpm's most of the time.

[brad black]

i check it at all rpm up to 6,000 or more and see what happens and then choose a best compromise from there as required.

i'll have to rewrite my report to make that clearer. 

[booger]

I just sync it at 3k and call it good. I usually don't have any help and find that 3k is all the fast idle lever will give me with the air bleeds closed. I only have two hands. If anybody has any tips on how to get at the sync screw easier let me know, I'm using an 8mm box end and a butterknife with the tip bent at a right angle. I'm seriously thinking about buying a right angle gear drive screwdriver for this purpose because syncing the throttles on this bike is a bit of an annoyance what with having to lift the tank and remove the airbox, zip tie the two fuel supply lines out of the way and STILL not having enough room to get at the screw. Pain in the ass I tell you.

[2 Wheel Wanderer]

@ Brad I think the report is awesome, what Ducati says in their manual is just inferior information.

@ bergdoerfer I just take out the air box, it takes me about 5 mins to pull it off. It just makes syncing so much easier.

[booger]

I take the airbox out too, still a pain to get to the screw

[2 Wheel Wanderer]

I take the airbox out too, still a pain to get to the screw

Duh I shoulda read further, you did mention that. I use a long thin headed screw driver and thread it through the frame from the left side of the vertical  head. It hits the slotted screw at a good angle and makes adjusting it pretty easy.

[scott_araujo]

Duh I shoulda read further, you did mention that. I use a long thin headed screw driver and thread it through the frame from the left side of the vertical  head. It hits the slotted screw at a good angle and makes adjusting it pretty easy.

+1.  I have a long screwdriver just for this.  Pretty easy to get to if you unbolt the oil cooler and let it hang down.  A flashlight to look in there and find the screw is essential.  No need to remove any part of the air box.

Scott

[booger]

+1.  I have a long screwdriver just for this.  Pretty easy to get to if you unbolt the oil cooler and let it hang down.  A flashlight to look in there and find the screw is essential.  No need to remove any part of the air box.

Scott

Scott I tried this after you told me last time I complained about it; lo and behold the slot head on the adjustment screw faces the rear of the bike. So dropping the oil cooler and fishing a long screwdriver in from the front won't work. Still a pain to get to the adjustment screw.

[scott_araujo]

Sorry man, guess mine's set up differently.  The screw head on mine faces forward.

Scott

[brad black]

the later throttle bodies (2006 sometime onward?) are made by bing i think and do have the balance screw facing backards in an impossible to access position.

[seevtsaab]

If i can get a home made manometer hooked up I'm doing mine today.
The balance 'screw' on mine is a is a small nut, facing rear, 05 620 (Bing).
Airbox off, I'll strap some cloth over the butterflys.

[2 Wheel Wanderer]

seevtsaab, we have the same bike, I do the same thing.

So, for months I have had the problem of syncing the TB's vacuum  then measuring the CO only to have the horizontal  @ 5% and the vertical at 2%. The bike is basically un-rideable, If I set the CO at 5% for both cylinders, at higher rpm's the bike vibrates so much from the unbalanced vacuum  that I don't want to ride it for fear that something really bad will happen. I also tried to set the CO through the trimmer so that one cylinder would be at 6.5% and the other at 3.5% then set them both at 5% through the air bleeds but the vacuum would go too far out of sync  and was still too rough.

I started a couple threads last year relating to this problem. I even had the loose valve guides changed (exhausts were loose one was at the service limit and the other was at twice the service limit) bit it didn't help, the CO values stayed the same.

I've tried to tackle this problem from 100 different directions. Last night I was at a buddies havin some beers when I found myself thinkin about my friggin bike once again and how there must be a solution to the problem, something that I have missed.

I thought about the horizontal cylinder getting way more vacuum than the vertical and started going through each piece that leads to the engine (pretty simple, air box, TB's and the manifolds). I knew it couldn't be the air box, the problem occurs with it off so that's out. It's either the TB's somehow or theirs a leak in one of the manifolds (I'm thinking the vertical one cause that's the one with the low CO).

Today I performed a quick test but before I did I checked the clamps that hold the manifolds to the TB's.

One thing I'd like to mention is last July my dealer had all four valve guides changed under warranty.

Back to the manifold clamps, I pushed on both of them, lo and behold they were both loose. When the dealer did the valve guide change they never tighten them. When I took the heads off I just left the manifolds attached to the TB's so I didn't think to check them.

So, to the test, I hooked up the manometer, synced the cylinders through the bleed screws (after tightening the manifolds to the TB's) and revved the bike to about 4K. What happened? Both cylinders stayed at the same vacuum pressure.

I will go back through syncing procedure and check the CO this week. I am hoping that this solves my problem once and for all. Ill post the results when I get em.

[seevtsaab]

Ah good news 2WW.

First went out for a nice 20 minute ride.
Man this thing smokes at idle - I'll keep an eye on that.

Hooked up a homebrew manometer (wow - easy!)  & did my TB sync.
Airbox off, cloth over TB's, bleed screws wound in.
Manometer works slick, I used water, I expected it to all get sucked out!

Balance was good at 4K, really changed at 5K, tiny tweek got it good at both 5K & 4K.
What a mean sounding tune up those MIVV's!
I had noticed slightly more vibes at 4K this year (mirror measure).

Yes that screw is a PITA facing rear. 5/16 locknut.

Bleed screws set out 1/4 turn where they were.

Bike runs great, I'll watch the tailpipe smoke, would love to check CO%.