Balancing by ear better than guages

[Guest Nigelstephens]

I bet that got your interest!

 

No I don't claim to have super human skills at balancing a Guzzi. However, this is my story...

 

I bought a Sport 1100 i (97) in Feb this year and have frequently balanced with guage and tried various methods. The problem is that it seems good at first but after a few days commute the tickover and part throttle go out of adjustment and the engine feels lumpy again.

 

Recently I tried a different approach and two weeks later the balance is spot on with engine pulling smoothly from tick over.

 

What I did differently was to balance as usual at 2500rpm with guage and then adjust at tick over using the air bleeds. Then a opend the throttle slightly using the grip and played with the connecting rod adjustment up to a turn either way to get the balance even better. After a few blips of the throttle and smaller adjustments I felt that it was as best as I could get it so I then adjusted the bleeds again and then the linkage. After several cycles of this it was spot on.

 

My guess is that the syncronisation by guages is not accurate in my case becasue of differences in valves, cylinder compression or something else. I'm pritty sure there are no air leaks. I use a single guage with a valve to switch between them so that is not a problem either.

 

Has anyone else had a similar experiance?

 

p.s. I have the MY16M installation so after balancing I set the TPS to an indicated value to 55 by turning the TPS on its mounting screws. I dont use voltage adjustment as no need. It works with a different range. (very loose interpretation of the difference). It is simpler to not have to wory about the very fine 150mV adjustment!

[Guest ratchethack]

Nige - did you check for a partial blockage in one o' the manifold barbs?

[docc]

It does help to spin a jam nut against the white adjuster knob to keep it from 'walking.'

 

I use mercury sticks so the cylinders can be read simultaneously. Last time I synched at an even higher rpm (4000) . The side stand scored about a foot long stripe in the floor and the vibration tossed the volt meter on the floor. $50 tuneup

 

 

The mercury always has a lttle water on top. I've even tried storing them next to a dehumidifier but still have the water. How would you guys read the water? I've chosen to ignore it as negligible since a water manometr requires such a large column and this is never more than 1/4".

[Alex-Corsa]

Ballancing should be done at the right way ant with the right values (TPS voltage) for every ECu needed.

For my Sport 1100i Corsa these are TPS volt. at = = 150mv +-10 and with the rods connected 385mv+-10 at the stock IAW 1.6M

 

Tricky part is to set the 2 values of tPS , one with the TBs dissconnected and on zero deg and the other with the TBs connected at 3.2-3.6 deg.

1.I quick synchronise the TBs with the vacum meter and then I adjust the 1st TPS voltage at 0 deg at set the pot tight at it's place.

2 .Then I do connect the TBs and adjust the TPS voltage by screwing-unscrewing that spoon like holder that joins doth TB's (right end of the connecting bar), with the assist of 2 pliers

3.Then I do a further synchronisation (micro adjustment-since I had done a sync at the start)) of the white screw head on the left side, as well as the air bleeds and it is ready.

I have done so many synchs that I can adjust the airbleeds by ear if I don't have a vacum meter (but only these)

 

As I said the tricky part is to have both voltages at both positions correct.

Explanation

Occasion 1

Now if you set the voltage at 0 deg correct and then when the TB's are connected you move again the potentiometer to set the new value, the game is lost at 0 deg the voltage will change.,once set at 0 it should be hold in that place. That's why I do step 2 adjustment.(Why you think there is a screwing holder over there? )

Occasion2

Now, assuming that even at both positions the TPS was the same and not any movement of the pot needed (in case you don't do the step 2 way) When synchronising with the white head screw of the left side you will again move the TBsenough so that the voltage will also change for good. That's why I do step no.1 with a pre synchronisation the next synchronisation will only need a micro adjustment of the screw and the voltage will stay as 'unchanged' as possible.

Now as you see in both occations you'll have the TPS voltage as close as it should be.

 

 

 

Important is, the engine temp as all should be done at engine temps of 53-80 C' deg, and with new set valve clearences..

Lattely I don't check TPs at every synchronisation but once every 6-8 months-.

 

So there you have it. A motor that will idle better than ever before and fuel consumption will be better as well.

 

 

There is a third occasion if you use a diagnostic programm that gives you the acces to adjust TPS from there, then perhaps you don't have to do synchron. this way since you can buypass and adjust the TPS through the programm.