throtle body synch & balance

[Delman]

Hello

trying to sync/balance the throttle bodies on my 2002 V11 following the thread here and have encountered a problem that i could use some help.

 

when the bike is attached to my home made manometer at idle 1100rpm then right cylinder has a lot more vacuum than the left, it is to a point that my manometer fluid reservoir (Gatorade bottles) for the left cylinder looses all fluids to the right reservoir and crushes from vacuum.

i did a test while the bike was running and attached to manometer, with the in take boot removed from the right cylinder TB.

when i cover the intake of the right cylinder TB with my hand and reduce the air in take by more than half the levels of my manometer equlises .

 

i have done the followings to the bike to get to this point.

 

new  rubber boots on both TBs

new fuel filter/air filter and plugs

valves adjusted to .06 and ,08

 TPS is set at 150 mv

right throttle stop is backed out all the way

synch rod is in slight tension and both TB plates are resting at the same position in relation to each other( i physically measured them)

air by pass screws are half turn out from close, this was the original setting

 

adjusting the synch rod  dos not affect the vacuum level

 

any help would be greatly appriciated  

 

thanks

         

 

 

 

[JBBenson]

Questions:

 

1.

Does your manometer look like this?: http://www.powerchutes.com/manometer.asp

2.

Does it show even vacuum when off idle? Through the RPM range?

3.

Are the throttle bodies clean on the intake side? Crud can prevent one butterfly from closing evenly with the other.

4.

I assume your 150 mV reading is with the connecting rod disconnected and the fast idle cam backed off (as well as the right hand throttle stop screw)? Check this first!

5.

What is the mV reading with everything connected and idling?

6.

Open the bleeds 1 full turn each.

7.

I think your test with removing the intake rubber and covering it with your hand is confusing the issue. Put everything back on and start again.

8.

Are you running the stock ECU map?

 

I hear your frustration. It might be a problem with your manometer and it's connections.

 

I could never get mine to balance perfectly at idle, one cylinder would always pull more air. But once "just off" idle they are perfect. So don't worry about perfection but smooth idling and sync "just off" idle. I used only the white knob for idle balance, even though it is frowned upon. Don't try to balance using the bleeds.

[Delman]

thanks for the thoughts JB

 

1. no my manometer consists of two  reservoirs that are connected to each other via a tube and each are connected oi the vacuum ports

2. no i don't get even vacuum at idle or higher rpms

3. TB s are clean

4.yes to all

5.i will get that in a bit

6.roger that

7.will do

8.the bike as far as i know is all stock 

 

i will try the simple manometer and report back 

 

thanks

[fotoguzzi]

 

 

adjusting the synch rod  dos not affect the vacuum level

 

 

thanks

the sync rod is for off idle adjustment (3,000rpm or higher) set first then use bleed screws for sync at idle.

[Delman]

you mean use both left and right throttle stop screws to adjust at idle

some say you don't need the RT throttle screw leave it backed out and some say use the RT to adjust at idle, i tend to agree with the later

[JBBenson]

Having done it every which way, I would:

 

1.

Back off the RH throttle stop. Unless you have some super high mileage bike where everything is worn out and sloppy, using both will make you crazy.

2.

Open bleeds one turn each. ("Micha's method") 1 turn is almost always right.

3.

Sync using white knob at idle. Like I said, some frown at this. Guess what? If they are synced at idle, it will be synced off idle.

 

When the throttles are open (>3k) the white knob needs to be moved a lot to make any difference in vacuum. This is because the small adjustments the white knob makes gets lost in the large flow of air coming through, and tiny imbalances in throttle vanes will be hard to see on any kind of meter, even the expensive one I bought.

 

You can turn the white knob and the throttles will appear to be in balance at higher RPM's. But they're not, which you will see when it drops to idle. Then you can use the bleeds to try to even it out, which is what I did, and then it idles worse than ever.

 

In short, the ultra tiny differences in throttle openings will be revealed at idle but will be lost at higher RPM's. If the idle is balanced, then higher RPM's will be balanced too.

 

Try "JB's" method, and sync the throttles at idle using the white knob. Turn 1/8 and blip throttle and let it settle. Keep doing this until it smooths out and is in balance. The idle will probably creep up as it smooths out (you can adjust this later using the LH throttle stop screw). It will never be perfect but you can get it close. Check "off idle" RPM's as you get it smoother, I bet they will be in sync too.

 

Yes, this method is backwards, but since your bike runs like crap right now, why not try it? I went through ever "method" before doing it this way, and now my bike runs like a sewing machine and pulls like a locomotive. The idle is steady at an indicated 1500, with small fluctuations due to ambient temperature, or certain trailing throttle situations, which i think is an ECU issue if anything (I am running modified ECU map).

 

I ended up buying this:

 

http://www.amazon.com/CarbMate-TS-111-Carburetor-injection-synchronizer/dp/B0022XTDQA

 

Guess what, the simple manometer is just as good.

[fotoguzzi]

you mean use both left and right throttle stop screws to adjust at idle

some say you don't need the RT throttle screw leave it backed out and some say use the RT to adjust at idle, i tend to agree with the later

no I mean the air bleed screws.. I always just use one throttle stop screw so the tie rod was not under tension.

 

Having said that, what JB says about the white knob makes complete sense.

[Delman]

what a difference, she idles at 1200 rpm runs like a sewing machine and pulls like a tractor 

gone are small hick ups coughs and hesitations just continious unintrupted power

now I see why you guys are in love with these things 

 

my synch rod was out from me fiddling with everything

the simple manometer works the best

 

here is how i did it

 

both air screws backed out one full turn 

adjust the TPS to 150 mv with synch bar off of RH TB and idle stop screw backed out and chock in natural position

attach synch rod to RH TB

warm up engine with fan blowing on engine

attach manometer

start the engine watching the fluid level in manometer so if won't get sucked in to the cylinder at the same time start turning the white knob to get fluid levels stabilized, if you see the fluid is going to get sucked in shut off engine and continue turning the white knob until you get the fluid levels close to equal

use the left idle stop screw to set RPM and in conjuction with the white knob fine tune fluid levels

rev up to 3000 RPM check manometer levels adjust with white knob

 

I was able to get the manometer levels even all the way around with a few tries

 

my thanks to JB and Photoguzzi for their thoughts

 

Delman

[Kingofgix]

I need a little help with this. I built an oil manometer and sort of followed the JB method. I did NOT fully back off the right hand throttle screw because a) I wasn't sure there was a "fully backed out" that involves the screw not falling out - can you really fully back this screw out? And when I backed out the right screw a bunch and tried balancing, the balance was so far off I had about 2 seconds to turn off the ignition before the oil got sucked out on the right side. Also, some where in my fiddling I had the idle at about 4000!

 

So I screwed the right hand screw back in to close to where it was ( not sure, I didn't count turns). Then I tried again and the balance was much closer. I then used the left screw and the white knob to adjust the idle and balance. I had idle at about 1200 indicated when I was done, and the balance was good both at idle and at throttle. Great! So I went for a ride:

 

Idle jumped all over the place during the ride. Anywhere from 1200 to 2500, and different pretty much every time I let it idle. Also, the bike is slow to come to idle, sometimes hanging up around 2000-ish, then slowly dropping. So what have I done wrong? Should I try backing the Right screw out again? It doesn't fall out?

[czakky]

Sounds lean, where was your TPS set?

Start from the top of the method described in the "How to" sub forum by Ryland I think.

You can back out the right hand screw too far but once it's flush with the inside of the metal it shouldn't be in play anymore. Look at the left screw to get an idea of how it works it is hard to see in there.

Sounds like to me your synch rod is out of whack. Make sure you take out any "backlash" when synching for the first time.

I don't think anybody gets this process totally right the first time.

Start from the top and you'll be amazed at how the bike runs when you get it right!

[docc]

Start from the top and you'll be amazed at how the bike runs when you get it right!

+1!

 

It is really important that your valves are adjusted, fresh plugs, and the CO has been "zeroed."

 

Make sure there are no vacuum leaks (like a missing cap on the vacuum taps), and it is fairly critical to set the baseline mV on the TPS with a fully closed throttle plate (the RH screw has lots of metal to seat in, so just back it out until it no longer protrudes from the front of the boss). Remember, the cold start "high idle" mechanism can  foul the right throttle as well.

 

Really dirty throttle plates and air bypass screw tips can mess with your idle, so clean these well and try the screws out a full turn.

[Kingofgix]

Thanks everyone. Well, I did pretty good on the non-electrical stuff. I adjusted the valves (.006/.008, so maybe a tad tight) and replaced plugs. But the TPS and CO settings are completely beyond me. I don't tend to do electrical, and I really don't know how to do these, so can't really do a proper job of this. But I hoped to adjust my way past the worst of it.

 

That said, I went back and tried it again. I tried a more secure method of attaching my manometer tubes and I may have had a vacuum leak before. Backed out the right screw a bit more, and readjusted. Got 1300 rpm idle and pretty good balance (balance does seem to drift a bit, but only a couple of inches of oil). Runs good and strong, very minimal surging below 4000 rpm (MUCH less that before), much smoother under hard accel., idle held steady at about 1300 Vauglia Borletti certified. It's actually quite good now. I can certainly live with it for awhile why I go back to electrical school.

[docc]

As Czakky sez: it'll get better and better every time you tune it!

 

Setting the CO requires software (guzzidiag) and cabling (an adapter cable and a OBD/FTDI to USB). Setting the TPS is best done with a "breakout harness." 

 

My three cables cost me $75US.

 

guzzidiag is free! (Thank you Beard/Paul Minnaert/Meinolf!)

 

Start with the TPS baseline setting. Replacing the Torx fasteners on the TPS with proper hex drives makes life better. ("Changing the fasteners to standard hex drives simplifies the process (4mm/0.7 thread pitch x 17mm long")

[Kingofgix]

Thanks again to everyone for your help. I do have a burning question that I hope someone can answer. There are basically two approaches to balancing throttle bodies:

A) http://www.obairlann.net/reaper/motorcycle/guzzi/balance.html

JBBensons approach above in this thread.

 

Approach A uses the right throttle screw in the adjustment procedure. Approach B does not use the right screw, but just has you back it all the way out and then use the left screw to set idle speed and the white knob to adjust balance. These 2 approaches beg the question:

Why is there a right hand screw? Is it necessary and if so, for what?

 

The fact that the bikes came from the factory with a right hand screw and that they came with the screw not fully backed out imply there is a need for this screw. The B approach, and the fact that it seemed to work for me, implies there is no need for theright screw. I adjusted the idle speed with the left screw and adjusted the balance with the knob. I accomplished everything I set out to accomplish without using the right screw( but I also didn't back it all the way out). My bike seems about 75% of the way there in terms of how it runs. Could I get it better by using the right screw somehow? Should I try backing it all the way out, adjusting somehow, or just leaving it alone?

[Scud]

Thanks again to everyone for your help. I do have a burning question that I hope someone can answer. There are basically two approaches to balancing throttle bodies:

A) http://www.obairlann.net/reaper/motorcycle/guzzi/balance.html

JBBensons approach above in this thread.

 

Approach A uses the right throttle screw in the adjustment procedure. Approach B does not use the right screw, but just has you back it all the way out and then use the left screw to set idle speed and the white knob to adjust balance. These 2 approaches beg the question:

Why is there a right hand screw? Is it necessary and if so, for what?

 

The fact that the bikes came from the factory with a right hand screw and that they came with the screw not fully backed out imply there is a need for this screw. The B approach, and the fact that it seemed to work for me, implies there is no need for theright screw. I adjusted the idle speed with the left screw and adjusted the balance with the knob. I accomplished everything I set out to accomplish without using the right screw( but I also didn't back it all the way out). My bike seems about 75% of the way there in terms of how it runs. Could I get it better by using the right screw somehow? Should I try backing it all the way out, adjusting somehow, or just leaving it alone?

 

I was curious about that too. This is what I've concluded - but it's not an official explanation:

• The left screw is for your primary, day-to-day, adjustments.
• The right screw is like a minimum, or a backstop, so you don't accidentally set the left screw too far closed. 
• For higher-mileage bikes, which have some play in the linkage, two stops can help keep things in balance at idle, because you synch TBs at higher revs.

I ended up setting the two screws so they both make contact at the same time.  My theory is that it will reduce fatigue or wear on the linkage. This is probably unnecessary, but it made me feel better.

 

Also, being Italian, not everything needs to have a rational explanation. All part of the character...