Balancing throttle bodies

[arveno]

Hello all !!

2002 Le Mans , followed the instructions found here for a decent tune up.

valve adjustment, tps setting etc etc.

I am using a motion pro tool to balance the throttle bodies but I don’t see the blue fluid raising in the tool columns.

as per instructions I have screwed all the way in the air bypass screw and backed them out one full turn .

the left and right side idle set screw are backed out.

I used the square white knob to somewhat let the engine idle.

if I play around with the air bypass screw nothing shows up on the tool.

Sometimes this happens to my carbureted Guzzi and I am always able to play with the carb until some fluid start showing up in the column of the tool.

this time not and since it’s the first time I am balancing throttle bodies… maybe I missed something?

any help highly appreciated.

ciao 

marco

 

 

 

 

[docc]

Hi, Marco!

So, first, screw in the left side idle stop screw until it bumps the linkage slightly open (you'll come back to that in the last step to set the final idle).

Start the motor an use the twist grip to bring the rpm up to 2000-3000, then use the white knob to equalize the vacuum on the balancing tool.

Some of these balancing tools have a "sensitivity" setting and some use restrictors to connect to the vacuum ports on the intakes. (It is connected to the intakes just ahead of the throttle bodies?)

[Desdinova]

While I haven't done this in a while, my #1 tip is disconnect all cables and make sure bottom is bottom.  There was a tiny of tiny small burr on my cable mechanism and so one carb was never actually 100% closing.  It tuned and ran great... with an occasional cough, but figured that was due to Stucci crossover, FBF pipes, intake, gas, PCIII map, etc etc...  nope...  that darn bur through everything off.  Once I found it..  it was like a got a new bike.   I cannot stress how infentecimally small this bur was. As I recall I only found it because the TPS dropped lower with the cable off and I only noticed it by accident.  

[arveno]

30 minutes ago, docc said:

Hi, Marco!

So, first, screw in the left side idle stop screw until it bumps the linkage slightly open (you'll come back to that in the last step to set the final idle).

Start the motor an use the twist grip to bring the rpm up to 2000-3000, then use the white knob to equalize the vacuum on the balancing tool.

Some of these balancing tools have a "sensitivity" setting and some use restrictors to connect to the vacuum ports on the intakes. (It is connected to the intakes just ahead of the throttle bodies?)

Yes the vacuum tool is connected to the intake right before the heads.

I set the engine to idle around 1100 and tool didn’t show any fluid coming up through the column.

i revved the engine to see if someone fluid will show up but  didn’t .

 

i will try again from scratch.

bike runs great especially after tps setting but I can tell the throttle bodies are not sync 

thank you for the help… will report back.

 

btw the v11 engine is awesome 😃

 

 

[docc]

Some balance tools also have a "storage" setting that blocks the vacuum pathway in the tool. My Motion Pro mercury sticks have this. There is a hose that has to be physically moved from a blocked port to an open port on the back of the tool.

 

[arveno]

24 minutes ago, docc said:

Some balance tools also have a "storage" setting that blocks the vacuum pathway in the tool. My Motion Pro mercury sticks have this. There is a hose that has to be physically moved from a blocked port to an open port on the back of the tool.

 

Mine is the white and blue with 4 columns.

i have a picture but it’s too large to be posted .

It’s sold for about 100 bucks or the usual websites.

I will try to play with it .

thank your again.

 

[arveno]

Maybe I have to do this calibration first .

 

[docc]

Yeah, I would not wind on the white knob anymore until the balance tool is set up.

There is a mechanical method to pre-set the balance at idle.  I think @gstallons posted this procedure. Might be a way to get your throttle rod back close to balance before the Balance Tool can be used . . .

[Randy]

I had a Motion Pro using mercury that worked well but then it got to where you couldn't get mercury any longer. Purchased the blue fluid version and still could not get a good balance even with calibrating it, etc.

Bought one of these and never looked back: http://www.carbtune.com/carbdtls.html