Synchronization knob and throttle bodies

[Kiwi_Roy]

Hi all, I am slowkitty's mate who held responsible for draining the scura battery with multiple starts last Sunday.

 

 

 

 

May I ask why do you need both throttle stop screws? I read that the right one can be left backed-off, and the left used to adjust. Would not the left just hold the adjustment by itself?

 

Kitty, I think a high mileage bike will need the use of right throttle stop screw to take up the slack in the linkages and ball joint because of wear and tear.

 

Phang

Exactly

[slowkitty]

Making a second attempt this weekend.

 

During my last attempt, I tried to use the syncro knob to balance the throttle bodies but it did not seem to have that effect. Any idea as to what could be the cause of that?  Just want to have a checklist to ensure that I got the parameters right.

 

Thanks  

[Kiwi_Roy]

The knob changes the length of the link between the two butterfly levers, it must effect the opening of the RH throttle relative to LH throttle.

 

What method are you using to measure the vacuum?

 

If you are using the one screw method the link is in tension holding the RH throttle open

 

Balance idle using air bleeds (same throttle left and right)

    

 

Blip the throttle, change length of link with white knob to get the same throttle opening at speed

   The air bleeds have very little effect at high speed because the size of their opening is tiny compared to the butterfly

 

With the one screw method chances are if you touch the knob you now have to re-do the idle air bleeds again

 

 

 

It's a job that takes a few times before you get the light bulb to turn on, just figure out what each step is doing and what effect it may have on the previous step.

 

If you open the air bleeds since you are not moving the butterfly the TPS Voltage is not changing but the idle speed is going up therefore the mixture must be getting leaner, If you close the air bleeds without moving the butterfly the idle speed is going down, the mixture is getting richer. So you can see it's possible to control the mixture at idle speed by using a balance between butterfly position (idle stop) and air bleed.

If you use the idle stop of course it throws off the 521 mV you so carefully set back at the top of the thread, that's ok it was just an interim step.

 

The first time I attempted it I got right screwed up

[slowkitty]

The knob changes the length of the link between the two butterfly levers, it must effect the opening of the RH throttle relative to LH throttle.

 

What method are you using to measure the vacuum?

 

Hi,

 

Using a Twinmax.  So here goes my very brief checklist with a few questions, please feel free to comment if I err in any way:

 

1. Back off RHS throttle idle screw completely, no contact. Choke also disconnected. 

 

2. Disconnect the rod at RHS ball joint.

 

3. Get 150mV on ignition on only, no start. Qn: what position should the LHS throttle idle screw be? Just touching or no contact?

 

4. Close fully both air bleed screws. Re-connect syncro rod. Qn: Does it matter how many turns into the ball joint or it does not matter so long as the rod is secured and locked? 

 

5. Start the bike and balance the throttle using TwinMax. Just work on the balance and not on the idling, that will come later. 

 

6. Use LHS throttle idle screw only to get the 521 mV.  Qn: This is to be done with bike started or no?

 

7. Open air bleed to say 1/2 to 3/4 to get 1100 - 1200 rpm - Qn: must be the same extent of turns both sides?  Will this affect the balance?

 

8. If cannot attain 1/2 turn, close LHS throttle idle by 15 mV increment until 1/2 turn is reached. 

 

9. Check balance at 2000 - 3000 idle using syncro knob. 

 

10. Check the idle balance again, adjust with LHS throttle idle screw if necessary.  

 

Anything else? Thanks loads, guys.

[Kiwi_Roy]

3) Since the rod is not connected it plays no part in setting the TPS which is on the RH throttle body however you need to close the LH throttle body all the way for the next step.

 

4) with the LH throttle fully closed adjust the rod so that the ball pops in place without moving the RH throttle

(now you have both throttles fully closed and the mV at 150. You can eyeball it to see that both the throttles leave the stop together, if not tweak the rod a little till they do.

 

5) No we are not ready to start yet

 

6) Adjust LH stop until the TPS measures 520 (this number is not cast in stone it's just a point to get the bike up near idle speed) the key is on but we haven't started the bike.  (now in theory both throttles are open the same)

 

7) Open the air bleeds, I use 3/4 it doesn't really matter. The air bleeds could have been done any time up to step 8 they have no effect yet. 

7a) Start the bike, I would now adjust the LH throttle stop to get the correct idle speed leaving the air bleeds alone.

(note how your setting of 520 mV is now out the window) Perhaps you would prefer to turn both air bleeds by equal amounts.

As I pointed out previously more mV  = more fuel for the same RPM

 

8) Adjust the air bleeds to get idle balance

 

9) As you say

 

10) No, tweak the air bleeds to get the balance correct at idle

 

I have no idea how well a Twinmax works, one of my trades is instrumentation so I prefer a "U" tube manometer filled with engine oil, it's the most accurate measurement you can get. The oils viscosity damps it out just right

[docc]

motowfo and I balanced his Coppa with the TwinMax then put my mercury sticks on it and found it was perfect.

[Kiwi_Roy]

Ok, I Googled the Twinmax, it obviously works using a differential pressure cell. that's very good.

I thought it was one of those devices with metal rods.

 

Still I can buy a lot of beer for $105.

 

Since it's so portable you should try riding with it, then you would be able to see the balance at open throttle settings.

[docc]

I've always used my Motion Pro mercury sticks, but sometimes think about putting this ALFA Romeo synch tool into service. The tubes are about 50 cm, so I'm rather sure it would require mercury.

[gstallons]

Yes...it will be up to the owner to decide how to procure the " stuff " that goes in them .

[Kiwi_Roy]

If all the tubes are connected to a common reservoir and it's not open to atmosphere you could use any fluid e.g. oil

The unused tubes would need to be plugged off.

You would fill it with oil to a point half way up the tubes

 

Show me a picture of the rear and reservoir and I will elaborate.

 

One has to wonder what happened to the mercury that was there before.

 

Your Guzzis are spoilt, Persian rugs to sit on

[Trevini]

Ok, I Googled the Twinmax, it obviously works using a differential pressure cell. that's very good.

I thought it was one of those devices with metal rods.

 

Still I can buy a lot of beer for $105.

 

Since it's so portable you should try riding with it, then you would be able to see the balance at open throttle settings.

 

 

I have a Twinmax.  Works very well.  The only slight bugbear with it is that the calibration control is very sensitive and takes a bit of patience to set accurately.  Overall, great piece of kit.  I also have a Morgan Carbtune (metal rod type) which I've used for years. That also works very well, especially on multis rather than twins.  Of the two, the "go to" one is the Twinmax for both of my bikes. 

[slowkitty]

Hi guys ....

 

Here's how it went ....

 

Cleaned the throttle bodies, especially the spring mechanisms. Also cleaned the air bleed screws which were sooty. Also cleaned the plugs. I didn't have the stock so ran Bosch W7DC.

 

Got the 150mV and the 520mV.  The bike runs better, at 1/2 turn air bleed.  At fully closed the idling is bad.  At 3/4 turns the bike seems to falter intermittently.  Thanks Roy for the air bleed opening tip. It is contrary to the sticky post procedure but seems to work for me. 

 

2 main problems:

 

1. I lost my tacho. Totally dead.  Will read up and maybe get one.

 

2. I failed to balance the cylinders. More suction on right as shown by the carbtune. On the Twinmax the deviation is less but visible. 

 

I tried to adjust the balance using the air bleed screws and it affected the idle badly.  Using the syncro knob also affected the idle but did not affect the readings on the carbtune.

 

I am stumped, but at least now I seemed to have gotten the idle set up ok.

 

Any views?    

[Kiwi_Roy]

The tacho gets power from the headlight relay, check your light is on.

It also needs a good ground.

There are two one way connectors (7) & (58)in the pulse signal from the ECU

 

http://www.thisoldtractor.com/guzzi007/schematics/1999_V11_sport.gif

The schematic shows 2 grounds, one for the lamp another for the electronics.

 

Might I suggest a different method

Leave the LH idle stop where it is (520 mV setting), take the linkage off

When you take off the linkage the TPS mV should drop back to 150 (RH throttle fully closed, I assume you are only using the LH screw to this point)

Wind the RH idle stop in to get 520 mV

So now in theory both left and right throttle bodies should be the same correct?

(the linkage is still disconnected and the bypass screws are both still 1/2 turn)

Start the bike and using LH idle stop fine tune the balance.

If the revs are too far off turn both idle stops in or out by the same No of flats, it should stay in balance.

 

At his point if the bike is idling a little rough you could try combinations of air bleed/throttle stops to get the idle ok

 

Now you have the idle speed and balance bang on re-connect the linkage adjusted so it doesn't upset all the hard work.

 

Now try the high speed balance using the knob, it should not upset the idle.

 

Sooner or later you will find a happy combination of different methods,

 

 

One thing, is it possible you have a more serious problem like a burnt valve that is throwing it off, a compression test perhaps remembering to hold the throttle wide open as it cranks over.

[docc]

If all the tubes are connected to a common reservoir and it's not open to atmosphere you could use any fluid e.g. oil

The unused tubes would need to be plugged off.

You would fill it with oil to a point half way up the tubes

 

Show me a picture of the rear and reservoir and I will elaborate.

 

One has to wonder what happened to the mercury that was there before.

 

Your Guzzis are spoilt, Persian rugs to sit on

(Not to hijack the thread, I hope) Back is sealed, fill tube on right, reservoir appears to be about 1" x  4".

 

Something heavier than motor oil?

[Kiwi_Roy]

I'm guessing that when the unit is not in use all the mercury would disappear into the 1 x 4 reservoir so its really 4 separate vacuum gauges.

It may still have mercury in it but I wouldn't use it that way. Mercury is now considered a hazardous substance, spill just one drop on your garage floor and it will put you over the current "Safe Limit"

 

As it was it would compare the manifold vacuum to atmospheric pressure so it needed mercury.

 

If you fill it to the point say 25% full scale and the reservoir is sealed it will act as a differential type comparing one manifold to the other (not to atmosphere) so it doesn't need a heavy fluid. The unused tubes would also need to remain capped otherwise you will suck air

 

With oil it will also be about 15 x more sensitive.

 

Really I think you should just screw it on the wall as a talking point.

 

I have my manometer filled with oil, it rarely goes more than about a foot out of balance before I shut down and tweak the screws.