Running rough below 4K

[dlaing]

Then when I have the idle speed right, I loosen the TPS and set it to 3.6 degrees...or roughly 485mv.

3.6 degrees should be 525mv, unless some ECUs are different than others

http://www.mphcycles.com/Technical/tpsexcel3.htm

[Guest penat]

Hi Guys,

Did a first home tune-up,tourqed heads,adjusted valves to euro spec,changed ,gapped spark plugs,balanced Tb's,adjusted TPS.Bike running pretty well but below 4k she will back-fire(more of a burble) and be a little rough on off-throttle.Checked TB's balance and TPS today and were spot-on.Where should I concentrate on as a possible fix.I know a PC 3 may help but feel I should get it closer without.

Thanks,

Michael

02 Scura with MG Ti + ECU

 

 

 

i had the same problem , and toke the bike to the shop, i live in Tijuana medico , so the mechanics really suck, i toke it to 3 different ones , nothing work until i change the exhaust because one was damage and it stop,so ...

its was the exhaust

!!check the gaps on the slip on part!! of you just tide it up it probably wont do a lot , they half a welding point take it of and redo it.

[dlaing]

Also,do most of you,disconnect TBs,back out RH idle screw,key on/not running method to get the 150mv reading?

I only do the 150mv reading about once per year.

I do it with engine off not running, which gives a lower reading then the Carl Allison/Will Creedon method.

I then reconnect linkage, balance high rpms (no need to go higher than 2500 RPMS) and with air screws open one turn (not sure if this is best way).

The left side always pull harder than the right at idle when balanced at higher RPMs.

I set idle to a compromise between 525mv unadjusted TPS and just over 1100 Veglia RPMs.

I then go back to the balance, turning in the left air screw no more than half a turn(not sure if this is best, but I am afraid to have them too different.)

Still I get the left pulling slightly harder at idle and right pulling slightly higher RPMS.

So, I set the right set screw to hold the right open.

When setting right set screw, watch the TPS reading. When it just starts to raise TPS, you are home. Then back out the left set screw half a turn or until idle balances.

Check idle, if OK then you are done.

It may take some going back and forth between balance and idle.

Don't let engine get too hot.

This method seems to work well for my bike as it may be a lemon and does not seem as well balanced as others who get it perfect by ignoring 150mv, air screws, and right set screw.

I have tried the other methods of not using air screws and set screws to balance, but I don't trust such a large compromise between balance at various rpms.

[dlaing]

i had the same problem , and toke the bike to the shop, i live in Tijuana medico , so the mechanics really suck, i toke it to 3 different ones , nothing work until i change the exhaust because one was damage and it stop,so ...

its was the exhaust

!!check the gaps on the slip on part!! of you just tide it up it probably wont do a lot , they half a welding point take it of and redo it.

Good point!

Welcome to the forum!

I am sure you know about Sonny Angel Motorcycles, north of the border.

And http://socal-guzzi.com/PHPBB/ great place to hook up for rides.

Sometimes we make it to Tecate for the beer garden And the more adventurous ride dual-purpose bikes in Baja.

Good luck finding a Transmission.

If you get one from a crash be sure to check mount points for cracks.

You may want to post the add elsewhere, like Guzzitech and WildGuzzi.

[Mr. Bean]

3.6 degrees should be 525mv, unless some ECUs are different than others

http://www.mphcycles.com/Technical/tpsexcel3.htm

 

Mine has never lined up like the list you posted. It was one of things that always confused me when I was trying to tune my bike according to settings like this. When I spoke to the folks at MI, they told me 3.6 degrees should be around 485ish. On my bike it is right at that. I thought it sounded too low also, so I tested it after I set it to 3.6. Now I jut use the software and ignore the mv settings altogether. I've noticed in looking thru various manuals...even the ones from Guzzi that they specify different degree settings for idle. Anywhere from 3.2 to 3.8 depending on which manual I'm looking at. I'm guessing that there must be different CPU versions...not sure though

 

Randy

[BrianG]

This air bypass thing has me (and apparently a number of others here) confused.

 

What is it really for? Is this device an idle mixture compensator, or something else?

 

If it is simply an idle mixture compensator why are some people using it to adjust idle speed? Improper mixture will vary idle speed all right, but because of a very wrong reason!

 

 

This imbalance should not be adjusted with the right set screw, use the bypass screws to achieve a good balance. That's what they're meant for.

 

also.....

 

To my way of thinking, matching vacuum readings at about 3000RPM matches TB flow where it matters, at mid range. Subsequent matching of idle vacuum should be a secondary consideration for performance, but may be important for idle quality.

 

My thought on setting idle vacuum would be to set idle speed with the left TB idle stop and then bring the right side idle stop to the vacuum balance point, just so that the right side throttle spring load isn't resting on the throttle cross linkage at idle. All things being equal, balance attained at 3000RPM should translate down to idle speed fairly well, and trimming would ideally unload the throttle linkege.

 

What say you??

[Mr. Bean]

This air bypass thing has me (and apparently a number of others here) confused.

 

What is it really for? Is this device an idle mixture compensator, or something else?

 

If it is simply an idle mixture compensator why are some people using it to adjust idle speed? Improper mixture will vary idle speed all right, but because of a very wrong reason!

also.....

 

To my way of thinking, matching vacuum readings at about 3000RPM matches TB flow where it matters, at mid range. Subsequent matching of idle vacuum should be a secondary consideration for performance, but may be important for idle quality.

 

My thought on setting idle vacuum would be to set idle speed with the left TB idle stop and then bring the right side idle stop to the vacuum balance point, just so that the right side throttle spring load isn't resting on the throttle cross linkage at idle. All things being equal, balance attained at 3000RPM should translate down to idle speed fairly well, and trimming would ideally unload the throttle linkege.

 

What say you??

 

 

Good question...Only passing along what I've been told, is that the bypass screws provide a reliable method of allowing a fixed amount of air at idle. It is more reliable for the majority of air needed at idle because it is not as subject to variances in things like temp and pressure as the multi-part mechanical throttle linkage assembly is. I used to keep my by-pass screws open 1/2 turn per the Guzzi manual. My idle speed now is MUCH more consistent regardless of engine temperature or weather with them open 1 full turn. Before, my idle speed could vary anywhere from 950 to 1200 rpms depending on how I was riding...cold weather, stuck in heavy traffic, cruising along and coming to stop, etc. Now it is very consistent at around 1150.

 

The guys at MI told me that setting the TB balance at around 1800 rpm is much more accurate than above 3000 rpm. They said that at higher rpms, the balance is effected more by basic combustion chamber properties and the like than the throttle flaps themselves. My own deduction in this (take it for what it costs..nothing!) is that the percentage difference in each opening causes way more effect when they are each just barely open than they do when they are open more. For example, a variation of 1/2 mm between them is very noticeable when each is only open 1mm, versus the same 1/2 mm variation when each is open 20mm. I used to set my balance at between 3000-4000rpm. At take off from a standing start, the engine wasn't very smooth until the rpm's got up to around 2500 or more. Now with the TB's balanced at 1800, it is very smooth at 2000 to 2500 without losing any smoothness at the 3000-4000 range.

 

I also screw in the right set screw just to the point where it touches the plate to "take the load" of the linkage. Probably doesn't really accomplish anything for the linkage since anytime the throttle is opened at all, the full "weight" of the right side is being born by the linkage anyway...but it makes me feel better . On my bike, it also doesn't do anything for the balance at idle either since my right TB would need to be backed off a bit to be perfect at idle..not advanced. I assume each bike would be slight different in this case since these are all essentially handmade parts on a handmade bike. I tried to compensate for this very slight misbalance at idle with the bypass screws but then I had to readjust the linkage rod for the critical 1800 rpm balance...which had the effect of eliminating the effect of the bypass screw....this is how I end up chasing my tail if I start messing with the bypass screws.

 

Again...I can't take credit for this procedure, but after trying many different tuning methods I felt the need to talk the folks at the dealer...this is what they do and it sure works the best of anything I've tried before on my 04 model.

 

Randy

[dlaing]

I used to keep my by-pass screws open 1/2 turn per the Guzzi manual. My idle speed now is MUCH more consistent regardless of engine temperature or weather with them open 1 full turn. Before, my idle speed could vary anywhere from 950 to 1200 rpms depending on how I was riding...cold weather, stuck in heavy traffic, cruising along and coming to stop, etc. Now it is very consistent at around 1150.

I have experienced the same.

 

On my bike, it also doesn't do anything for the balance at idle either since my right TB would need to be backed off a bit to be perfect at idle..not advanced. I assume each bike would be slight different in this case since these are all essentially handmade parts on a handmade bike.

Thanks for mentioning that.

I was wondering if all the right cylinder idle vaccuums were stronger due to firing timing, but that puts an end to that theory.

Although there must be some effect of timing on balance.

[dlaing]

Mine has never lined up like the list you posted. It was one of things that always confused me when I was trying to tune my bike according to settings like this. When I spoke to the folks at MI, they told me 3.6 degrees should be around 485ish. On my bike it is right at that. I thought it sounded too low also, so I tested it after I set it to 3.6. Now I jut use the software and ignore the mv settings altogether. I've noticed in looking thru various manuals...even the ones from Guzzi that they specify different degree settings for idle. Anywhere from 3.2 to 3.8 depending on which manual I'm looking at. I'm guessing that there must be different CPU versions...not sure though

 

Randy

I'll have to check mine against TuneBoy.

My workshop manual says 3.2-3.6° in one place and 3.6±0.5° in another place.

But they say to set TPS with linkage disconnected to 150±15mv and to set the higher number with the set screws, not at the TPS.

From MPH's chart that translate to about 475-525mv and 463-587mv

If 3.6° = 485 then they would translate to about 435-485mv and 423-547mv

MPH has other numbers here:

http://www.mphcycles.com/Technical/Technical2.htm

1060 +/-50 3.6 +/-.3° 1.90%CO 1/2 Turn air

Slightly different than owner manual

1000-1100rpm 1.5%CO

CO very different than workshop manual

27CARBURATION PROCEDURECheck of the starter control cut-outIn the event that the throttle valve potentiometer has beenreplaced, removed or deregulated, before carrying out anycarburation procedure it is necessary to adjust it onceagain, following the below instructions:•Detach the connection rod between the throttle bodies;•Using a tester, check that the potentiometer with theclosed throttle body indicates150 mV. If the values aredifferent, loosen the two fastening screws andreposition it correctly;•Adjust the throttle bodies using the adjustment screwuntil bringing the idling speed opening to 3,2°-3,6°;•Attach the connection rod between the two throttlebodies;•Check that the by-pass screws are completely closed;•Bring the RH side body’s adjustment screw flush;•Connect a vacuometer to the sockets on the intakemanifolds;•Adjust the cylinders’ equalization using the throttle bodyadjustment screw;•Check that the equalization is maintained inprogression;•Check that the engine’s idling speed is 1050 r.p.m.;•Bring the oil to a temperature of 80°C;•With the engine idling, check that the CO value isbetween 3% and 3,5%. If this is not the case, adjust itby varying the Trim.EPROM value on the software’sActive Test page.•Check the r.p.m. and the equalization of the twocylinders once again.N.B.Between the cylinders, a maximum unbalance of0,3% for the CO and of about 7 mbar for thevacuum should be taken into account.

 

and

 

 

28FUEL SYSTEMRULES FOR CARBURATION, REGULATION ANDADJUSTMENTConnect the PC to the diagnosis socket and thevacuometer•Detach the throttle body rod, 1/2 turn by-pass;•Using a throttle adjusting dowel, regulate the throttlepotentiometer on the RH throttle body to a value of3,6°±0,5;•Equal the vacuum in the two cylinders by regulating itif necessary, through the throttle adjustment dowel onthe LH throttle body;•Connect the throttle body rod;•Check the vacuum at different r.p.m, if necessarysynchronize it using the adjustment handwheel;•Detach the vacuometer.The idling speed must be 1050±50 RPM.N.B.If, after this procedure, the idling speed is notwithin the indicated range, check thepotentiometer by fitting the special cableconnected to the digital tester and positioningthe completely closed throttle on the attached rod.The correct value must be 150 mV±15mV.CO% CHECKShould the engine warming-up procedure be carried outon the bench, the maximum speed shall range between2000 and 3000 r.p.m.•Connect the PC to the diagnosis socket and the CO tothe two special sockets on the exhaust manifolds.•The CO% test must be carried out when the engine isidling, at least 2 minutes after engine ignition (due tothe automatic enrichment) and with an engine oil tem-perature of 70°÷80°, indicated by the engine oil sensor.This can be viewed on the Dashboard page of the MDSTprogramme.•Check that a CO% value ranging between 3,5 and 4,5.is detected for both cylinders.An unbalance of ±0,5% between the two cylinders isacceptable.•If the CO% value does not correspond to the prescribedone, adjust the trimmer using the Active Test pageand following the diagnostic adjustment procedure onthe PC.

[jrt]

Using paper clips on the two outside wires.

 

This part raises a red flag for me. I used sewing needles- they're smaller and fit up into the connector better. An alternative is to use one strand from multistrand wire and weave that into the contact. Go small. I don't know if this is your problem or not, but it will improve your technique, I hope.

[Guest slowpoke]

Just a thought, 'has anyone fitted carburetors to a V11'? That's what they need! None of this crazy banter and intellectual nonsense on this website. (Truth be known some of you guys should be designing for Moto Guzzi). But let's face it: the bikes would be a lot easier to diagnose/service if they had Japanese carburetors!! And they would have more power! Would they pass EPA? Maybe so; maybe not. The point is, they have a bad system for fuel flow into the V11. I have a perfectly good V11 sitting in my garage and I am perplexed by the fuel system. I also have a Yamaha FZ1 in the garage that I am not perplexed with and use on a daily basis that goes like the wind but, I would still like to ride the Moto Guzzi before I sell it!

[BrianG]

Just a thought, 'has anyone fitted carburetors to a V11'? That's what they need! None of this crazy banter and intellectual nonsense on this website. (Truth be known some of you guys should be designing for Moto Guzzi). But let's face it: the bikes would be a lot easier to diagnose/service if they had Japanese carburetors!! And they would have more power! Would they pass EPA? Maybe so; maybe not. The point is, they have a bad system for fuel flow into the V11. I have a perfectly good V11 sitting in my garage and I am perplexed by the fuel system. I also have a Yamaha FZ1 in the garage that I am not perplexed with and use on a daily basis that goes like the wind but, I would still like to ride the Moto Guzzi before I sell it!

 

There is nothing better or easier than electronic fuel injection, in terms of accuracy, power, and efficiency. A well tuned carb is OK but tuning a carb to a modified engine is the biggest PITA! I, for one, am not sad to see that pile of jets and needles and slides and other crap find its way out to the dust bin!

 

With the electronic tools available now, you can tune a new map for almost any change you make to the power plant and know that it is accurate and specific. The days of jet swapping and spark plug reading are greatfully dead!

 

As for the fuel delivery system on the Guzzi....... you are right...... the fuel tank design is not far from downright stupid....... but that's not a EFI issue..... it's an Italian engineer issue!

[luhbo]

Understanding a carburettor, not to mention a carb/points combo, is way more difficult than understanding a motorcyle EFI/ignition system. If one wishes back these parts, then it seems as if he's not familiar with either of these systems.

 

Hubert