Which is most important - Falco fueling question.

[ThEGr33k]

... Throttle ballance or Air fuel mixture being right?

Im mostly meaning twins.

I know that when Aprilia made the trim pots adjustable on the 2001 RSV models they said that Throttle balance wasnt really an issue and that as long as they were similar thats ok, but the trim pots needed to be adjusted with the aid of a O2 sensor to within spec. This seems a little odd to me though, anyone able to explain why this is the case?

Reason I ask this really is that Setting the trim pots is all fine, but obviously if the stock map is out then all the trim pots can do is make the map work in certain places. So for example, on the throttle my bike feels fine, off of throttle I canget some popping and rough deceleration. I have got the throttle balance set to what feels the smoothest and the trim pots the same.

So basically, with me having the throttle balanced as best I can (for some reason the rear cylinder needs more vacuum to run smooth!?) is the only way to get it all perfect now would be to get a dual map sorted using a PC3 and dyno?

[AndyBrad]

surely if your af is wrong it wont matter a jot if the throttles are balanced as it will run rough all over anyways? and if your bodies arnt balanced its not going to run right at low rpm?

[hardhat_harry]

Air Fuel mixture screws don't exist on some variants of the SV I'm thinking US models and are usually siezed on all others.

The throttle balance screw is more important.

[ThEGr33k]

Sorry, its not an SV, its a Aprilia Falco (I know wrong forums ha ha). The two butterflies on my bike are fixed so cant fall out of balance. I have to balance using bypass screws...

Andy, Throttle balance on my bike only effects the low throttle openings, once the throttle is opened up the bypasses do very little. Also bad fuelling is generally masked as the revs get high (unless its really terrible) so its a double issue at Low RPM if the fueling is out and the balance too. There is also the fact that the fuelling could be bang on the money at 2000rpm but off enough at 3000rpm to cause rough running. Finally there is also that certain Throttle openings could be great and others feel bad at the same RPM (say cruising feels off but 60% throttle feels fine). Thats why the only real way is to setup with dyno... Get as close as possible.

One other question while im here. Can a PC3 be used to tune from tickover right upto max RPM max throttle?

[hardhat_harry]

I was thinking of the pilot screws anyway......

[yorkie_chris]

You need both correct
Use vacuum gauges, set it stoich at tickover by highest vacuum method, then balance

But you are saying you have no separate control over fuel and air for each pot, just one bypass bleed each pot right?

[ThEGr33k]

stoich, OK read about this, basically burning right, right? Can you explain what you mean byhighest vacuum?

I have A bypass screw on each cylinder and a CO pot for each. Makes it a bit of a balance act.

Thing is I think the fuelling is pretty off atm with exhaust and intake mods I got, and if I set both cylinders to same intake vacuum it runs off, though this is a common thing with these engines, no idea why though?

The problem with adjusting the CO pots is that they alter the base timing for the injectors, so I can set it up for perfect tickover but then it knocks everything else out...

Another clarification, A/F values. For cruising should be ~14-15? Deceleration ~17? And acceleration ~13?

[yorkie_chris]

Highest vacuum... sucking most based on same throttle position but adjusting fuel.

What is CO pot? an idle fuel adjustment or does it change air flow? (electronic or mechanical?)

[ThEGr33k]

Carbon Monoxide potentiometer I think it stands for. Its electronic, found on the ECU, and has One per cylinder. From what I can gather it sets the base timing for the injection, so its just a way to raise and lower the whole fuel map. Not really much use I don't think as like I say you can set Idle right but then throw out the map somewhere else, certainly feels like that when I have done some playing.

Highest Vacuum, not so sure it will work for my bike, does that rely on O2 sensor of some type? (or im probably being thick and miss understanding...)