Ryland3210

Interesting experience. If the TPS is calibrated at WOT, and left to its own devices everywhere else, then logic dictates it will not be optimum at low to medium throttle openings. It suggests that the engine is fairly forgiving of deviations from optimum, which is not surprising, based on the charts. However, while WOT performance is probably the same, less than ideal economy and part throttle performance would be expected. It is difficult to tell how performance is affected at part throttle. A variation of only a few degrees at, let's say, 10%-20% open can make a significant difference without being detected or measured when riding. Only a dyno test would make this easy to compare. I'll stick to calibrating at the idle, and just make sure the TPS reaches 4.87 at WOT. Why 4.87? Because the chart from TuneBoy shows the highest entry of 84.56 degrees, which corresponds to 4.87 on the MPH chart. Please be specific about your first statement. Obviously mixture does affect power output, and the relatively lean mixture at 4000 RPM with standard tuning can explain a reduction in power output. What do you mean by "rectified the mixture"?

[quote name='Skeeve' date='Sep 8 2007, 03:56 PM' All of which begs the question: is the 4k rpm flat spot caused by too much or too little fuel? If it's a lean stumble, then wouldn't it be interesting if the easiest fix is just to substitute the H-D tps in for the stock unit, rather than spending all the time & expense on a PCIII & mapping on an otherwise stock motor? It's simpler than that. Look at the fuel delivery chart at 4000 RPM, large throttle openings. It leans out compared to delivery at the higher and lower adjacent RPMs There are places in the charts like this, where fuel and timing entries make no logical sense to me. For example, at 4,000 RPM, if I had a Tune Boy, the first thing I would do is set the fuel delivery at the midpoint between the adjacent columns. My predictions is that your flat spot goes away. Here's another: between 5.18 and 21.46, at 3200 RPM on the ignition chart, timing is retarded compared to higher and lower RPM's. Why? If there isn't any preignition at the lower RPM, why retard the advance at 3200?

The Procedure below for adjusting throttle balance, air bypasses, linkage connecting rod, TPS and RPM is the product of contributions of numerous members of the V11 LeMans members, for which I am grateful. An important goal of the procedure was to make it easy, logical, with minimum trial and error guesswork. IDLE TPS/THROTTLE BALANCING TUNING September 9, 2007 First make sure the TPS is calibrated to 150 mv at fully closed as follows: disconnect the connecting rod, back off the right throttle idle screw and choke cam (make sure the choke cable permits full retraction of the cam (it didn't on my bike), then loosen the TPS clamp screws and rotate if needed. + - 5 mv can be obtained with a little effort. Next, close the bypasses, keep the right throttle idle screw backed off to put the connecting rod in tension, removing any backlash, and balance the throttles at idle using the connecting rod adjustment. Screw in the left throttle idle screw if the idle is too low to maintain. Do not use the choke for this purpose, because that would put the connecting rod in compression, introducing backlash. Now adjust the left idle screw for a TPS reading of .518 volts. + - .005 (corresponding to 3.4 degrees physical opening) can be obtained with a little effort. (Some riders have been known to also subsequently physically readjust the TPS (not the idle screw) to lean or richen the entire throttle range. However, loosening its screws and offsetting the TPS to a higher voltage, e.g. .539, will fool the ECU into adding more fuel, but it will also fool the ignition timing table.) Next open the bypasses to obtain the idle RPM at 1100 to 1200 while maintaining balance. Bypasses should be open 1/2 turn or more. If not, back off the idle screw to reduce the TPS in steps of 15 mv and open the bypasses to compensate until they are opened 1/2 turn or more. Check balance at midrange RPM as follows: A When checking balance at cruise RPM, make any fine correction needed using the connecting rod adjustment, then: B. Check balance at idle RPM. If OK, done, if not, rebalance at idle using the air bypass screws, and go back to step A. Option: Adjust the idle mixture trim potentiometer under the label of the computer for best idle quality, or use a gas analyzer if available. However, according to Guzzijack, "not an option on the V11Sport as it uses the 15M ECU - manual adjustment of the idle mixture potentiometer is only applicable to bikes with the P7/P8 or 16M ECUs - 15M idle mixture adjust is only possible via factory or aftermarket software." Once this procedure is completely successfully, in the future, minor changes in idle speed can be made simply by adjusting the left throttle idle screw. Since the throttle plates have been balanced, backlash between them has been eliminated, and bypasses have been properly adjusted to maintain balance at idle, these should be stable for many miles.

On my '04, I checked the tach against an extremely precise (relative to the tach) digital counter. It was spot on at 1100 and 1300 RPM. What makes me wonder about your situation is that IF the tach is driven by a signal from the ECU (as it is on some automobiles I know of), which monitors RPM for its own purpose, is it possible your ECU thinks the engine is revving higher than actual? If you look at the ignition chart, except for the anomaly at 3200 RPM (which I do not understand the reason for), the advance increases with RPM in the middle range, so your ECU would over-advance the timing if it thought the revs were higher than actual. Another possibility is that the tach itself is calibrated incorrectly.

It would be great to find a way to identify each other. Perhaps there will be an obvious meeting point, corner of the bar, or something like the table nearest the door? Does anyone know of any such place in the lodge?

[quote name='Skeeve' date='Sep 8 2007, 03:56 PM' All of which begs the question: is the 4k rpm flat spot caused by too much or too little fuel? If it's a lean stumble, then wouldn't it be interesting if the easiest fix is just to substitute the H-D tps in for the stock unit, rather than spending all the time & expense on a PCIII & mapping on an otherwise stock motor? Well, maybe, or maybe not. I've been involved in electronics, including specifying and purchasing many potentiometers over the years. Now, I'm choosing my words carefully: It would not surprise me to find that both of the potentiometers tested were made to the same specifications, and the difference in break point is simply typical production variation. Without access to the manufacturer's specifications, I remain unconvinced that the potentiometers are intentionally different. Even though they have different part numbers for the Harley and Moto Guzzi applications, the difference could relate something other than the transfer function. It would not be the first time I have seen the same part given different part numbers for different markets, or simply to set two different prices! I'm happy to be proven wrong about this, if the spec's are available. In any event, this does not change the draft procedure. I have added a note at the end suggesting that the left throttle idle screw can be used for occasional minor adjustments of RPM without having to use the bypasses and monitor vacuum balance, once the whole procedure is done. I have tried this out earlier today at various idle RPM settings from 1000 to 1500 RPM without any problem. So I think we are done with the procedure.

Terrific! That confirms two assumptions: The TPS is non-linear, but within the 3.4-10.4 degree range I analyzed, it is linear. The ECU does interpolate between the entries in the map. I'm off on a long ride just now, and look forward to digesting the whole report later today. Thanks for this info, dlaing.

Interesting. I'm not familiar with the term "sizings" in this application, and would also like to know how more about high temperature powder coatings. How high, and what color limitations, if any? Also, I would like to know which dyes used in anodizing are sensitive to heat.

Please review my draft procedure, which has been updated to what I think is a final version. :!: Thanks, John

OK, let's review the fundamentals: The ECU has no way to directly know the actual throttle position. That's the purpose of the TPS. If its voltage output is incorrect at zero degrees open, it must necessarily be incorrect at all throttle positions. Therefore it will definitely affect the"outcome". Regarding linearity, my analysis of mv/degree on the MPH table showed that not only is the TPS linear over a small range of rotation (which is true for linear potentiometers and for small changes in rotation for non-linear potentiometers) up to 4.1 degrees, but it is nearly perfectly linear all the way to 10.4 degrees. I discount the 3.9 entry of 567 mv as a typo, because if you insert 557 in the table in it's place, the linearity works out fine, at 111 mv/degree in that region. Perhaps it is non-linear above that range, but I think that's unlikely. Why? because non-linear pots are more expensive than linear ones, and any non-linear function desired can readily been created in the table, which is clearly non-linear as it is shown. I believe that is what is probably meant by the Weber/non-linear comment. So we get right back to the importance of calibrating the TPS sensor so its output is 150 mv with throttle closed so that the ECU inputs the actual physical position of the throttle. That way, the tables for fuel and ignition advance are accurate. As your quote points out, offsetting of the TPS will affect mixture, but it will also affect timing. Therefore, it is a better idea to modify the table than to offset the TPS, unless one studies the table and understands that both factors will change together. Now to review how the idle TPS setting might affect economy in a small way. Let's assume that the ECU interpolates the fuel delivery between the entries on the table (ANYONE KNOW ANY DIFFERENT?). For example, there is a change towards richer, from 1.99 to 4.18 degrees on the table in the range of 900 to 1300 RPM. Therefore, the larger the throttle opening (and with it, TPS voltage) the richer. Conversely, adjusting the idle stop screw for a lower TPS and opening the air bypass screws to obtain the target RPM will result in less fuel consumption at idle. How much? I think the difference will be so small, only a perfectionist would be concerned. I have been accused of that, to which I confess. Since I have already set mine up at 485 mv, I'll leave it there and save a little fuel. A side comment on the two ignition advance tables. I noticed the non-standard table advances the timing more at idle. In my experience, based on the numbers in the table, that will increase efficiency at idle, and require less bypass opening to obtain the target RPM. If I get a tune boy, one of the things I would do is advance the timing at idle from the standard 9 degrees at idle, and also as it shows in the green area. I would expect more power and less fuel consumption for the amount of increased advance shown. Of course, then it is wise to watch for pinging.

It appears to the me that the difference between Mr. Bean's 485 mv at 3.6 degrees and MPH's chart showing 524 mv at 3.6 degrees is explained by Mr. Bean's settings and measurements made without reference to the throttle closed voltage. If his was actually 111 mv instead of 150, that would explain his 485 mv. Therefore, I agree that Mr. Bean's 485 is not a valid number and another datum is needed. Let's look at the MPH chart: Within a small range of throttle opening, the change in mv/degree should be fairly constant. Here's what the math says: Degrees mv mv/degree 3.4 501 3.6 524 115 from 3.4 3.9 567 143 from 3.6, and 132 from 3.4 4.1 579 60 from 3.9, and 111 from 3.4 10.4 1258 108.14 from 3.4 I find it extremely unlikely all these numbers are correct. Assuming 108 is the closest, since it is taken over the largest range, then 150 + 3.4 X 108 = 517 (a difference of 16), and 150 + 3.6 X 108=539 (a difference of 15) These descrepancies suggest that the chart was constructed by measuring voltages, rather than based on the engineering theory, and that the actual TPS voltage was 134-135 mv during the test. If so, the most reliable is the 108.14 number. That gives us a revised table as follows: Degrees mv 0 150 3.2 496 3.4 518 3.6 539 As I indicated previously, it seems that it makes little difference whether one uses anything from 3.2 to 3.6, because the air bypasses will end up compensating for that when the idle RPM is adjusted to the 1000 to 1200 range. On top of that, apparently my tuning, just completed at 485 mv, corresponds to 3.1 degrees, and seems to run just fine. It also explains why my air bypasses had to be opened more than 1 turn. As dlaing pointed out, the MPH chart shows no difference in fuel delivery between 900 and 1300 RPM for the throttle settings in the range of interest. Therefore, it does not seem to matter which of the above TPS voltages one targets for. The air bypasses will simply be opened to whatever it takes to get to the target idle RPM. Since in that range the fuel delivery is constant, using a smaller throttle position will not result in saving fuel, as I had earlier believed when I thought fuel delivery would increase with throttle position (within that range). It still remains that by offsetting the TPS to "trick" the ECU could be used to richen or lean the mixture at higher throttle openings and RPM's above 1300. So where this leaves me is to change the target TPS to 518 at 3.4 degrees. 539 and 3.6 degrees would probably work also, but the lower number provides more margin for error in TPS calibration, to make sure the air bypasses are open a reasonable amount to achieve the idle RPM and make it easy to balance. I propose to set the idle RPM target at 1100 to 1200, and to leave out target air bypass settings. Before I cast this in stone, any further comments?

Here's my take on Mr. Bean's experience: I think it is very unlikely that his throttle closed TPS voltage was zero. It makes sense that it was near 150 mv. When he increased the throttle opening until the TPS was at 525 mv he was opening it farther than it would be at 485, therefore letting in more air. That explains why he had to close down his air bypasses to get the idle RPM right. In order words, holding the idle RPM as a constant, there is an inverse relationship between how far the throttle is opened and how far the bypasses are open. There is no mystery in this. Once the throttle plates are balanced, the more they are opened, the less open the air bypasses will end up to achieve the target RPM. If the throttle plates are opened too much, the air bypasses will have to be closed altogether. So the 485 mv setting happens to be low enough that the bypasses must be opened to reach 1060 or 1100 RPM. The advantage of this is then the bypasses can be used to conveniently balance the vacuums and fine tune idle RPM. Theoretically, although I haven't tried it, the same idle RPM could be reached by keeping the bypasses closed, and adjusting the idle adjusting screw. However, this means that the ability to balance using the connecting rod adjustment at cruise RPM and independently balance at idle using the air bypasses is lost. So here is a proposed summarized procedure to append to the draft procedure for those seeking perfection: A When checking balance at cruise RPM, make any fine correction needed using the connecting rod adjustment. B. Check balance at idle RPM. If OK, done, if not, rebalance at idle using the air bypass screws, and go back to step A.

The die cast valve covers can be anodized black or other colors. Hi quality die castings have a porosity-free skin on the surface. If quality is not very good, there may be "flow lines" where two leading edges of the molten aluminum come together without welding together or other surface defects. These are usually impossible to buff or polish out completely. I would classify the valve covers on my bike as high quality. They are very easy castings to make, whereas the Centauro shift lever castings I have seen are more difficult to make and were of poor quality. They had been sand-blasted, a remedial method commonly used in an attempt to make such defects less obvious. Anodizing is a process whereby the aluminum is the anode, the opposite of plating when it is the cathode. In the process the aluminum on the surface is oxidized in a solution that includes a die to generate the desired color. Black is the most consistent and easiest (except for clear). There is no negative effect on the temperature limit of the original aluminum. Die cast aluminum alloy generally melts at around 1150 F depending on the alloy. Powder coating I am familiar with on diecast parts for automotive sideview mirrors, for example, is baked at 350 degrees F to fuse the coating onto the surface near the coating's melting temperature. Therefore, temperatures approaching that level could cause the coating to melt. If you decide to go with copper plating, they will quickly lose their shine, unless they are clear-coated. For room temperature applications, it is common practice to clear coat brass bathroom fixtures, for example, which can get up to 160 or 180 F on the hot water side. I am not aware of a clear coating that can withstand 350 degrees, and I do not have expertise in this area.

Aluminum is chrome plated by first plating it with copper, then nickel, then chrome. The aluminum is not polished to a mirror finish. It is deliberately left with a matte finish which gives the copper a bettter bond. The copper is then mirror polished prior to the nickel and chrome platiing sequence. Heat is no problem as long when the plating is done well. The aluminum has the lowest melting point. Corrosion resistance is good.

Ditto for me.

Using your numbers, 524 mv minus 150 mv divided by 3.6 degrees equals 104 mv/degree. Therefore a TPS of 485 mv corresponds to 3.22 degrees. It simply means that if the bypasses are successfully opened up enough to obtain the same target RPM as with a TPS of 500mv or 524 mv, it seems to me the only difference is that the setup at 485 mv is leaner than at higher TPS settings. As throttle opening is increased, the bypass airflow is less significant. At some poiint, it becomes insignificant, so fuel/air ratio is the same regardless of the idle setup. Bottom line to me is: 1. For any idle setup, whether at 485 or 524 which has the TPS set to 150mv at full closed, cruise and acceleration mixture is essentially unaffected. Only the idle mixture ratio is affected. 2. Those who wish to modify the mixture over the entire range can do so by deliberately offsetting the TPS from standard calibration. 3. Balancing the throttle plates and bypasses in accordance with the most recent revision of the draft procedure is still valid.

My understanding is that the ECU determines how much fuel to inject based on inputs of engine temperature, TPS, and RPM. Let's assume the engine is warmed up to normal operating temperature. Let's consider what happens when opening the bypass settings from full closed while the TPS stays at .485 volts. As the bypass air is increased, if the RPM increases, it means the engine wants a leaner mixture, but at the same time, as RPM increases injected fuel will increase. On my bike, the vacuum increased along with RPM, so I believe the mixture was improving, towards the lean side. At a constant TPS voltage and throttle position, the more the bypasses are opened, the leaner the mixture. Reading between the lines of the recommended 1/2 turn for the bypasses, and an 1100 RPM idle speed, I suppose the Guzzi techs have the ECU programmed to deliver a slightly rich mixture when the bypasses are set there. If one ends up with bypasses more open than that, keeping the TPS calibration the same, the idle mixture will be leaner, but as the throttle is opened more and vacuum decreases, the contribution of the bypasses will diminish, so at higher RPM or higher loads, mixture will revert to the factory's intended mixture. In my case, when the bypasses ended up at just over 1 turn out each, I was happy to have a little leaner idle mixture, knowing that with the TPS calibrated and throttle plates balanced, I could expect better fuel economy without sacrificing acceleration. Personally, I think it is preferable to balance the throttles at low openings because at, for example, 25% open or more, a degree off balance for the throttle plates is much less significant than at or near idle. In fact, when I balanced the system in accordance with my draft procedure, I found the vacuums balanced out perfectly at 2500 -3000 RPM

I haven't seen any answers to your question above. Hopefully, Pete or another tech guru will reply.

The 10-20 mv higher and inconsistency while running now sounds like electrical noise, vibration of the TPS shaft or both. Doing the 150mv reading while running with right throttle completely closed must be a pain. I see no advantage to having the engine running for this test, except to eliminate a 10-20mv difference, which is a small percentage of a 4.850 range. I only see a 1-2 mv variation in the 485mv TPS voltage while running at 1100 RPM, so maybe my bike has some good grounding and/or less electrical noise radiation.

See my edits in the draft procedure, taking your comments into account. There have been many varying opinions on what voltage to adjust to. I think the target of .485 allows newcomers to have a specific target so they do not have to wonder where to adjust to within a range. I added the comment about readjusting the TPS for those more advanced tuners. On my bike, there was no big difference on voltage readings whether the engine was on or off. Since the reference voltage is regulated, it theoretically should make no difference. However, if the battery is weak enough to drop its voltage below its regulating range when the engine is off, that could be a factor. This could be overcome by connecting a charger to the bike so the voltage is always at the running voltage. I found I did not have to do this. Also, if there is a poor ground at the ECU or in the charging circuit, that could cause a problem. On the CO, I think the "gas analyzer" comment is general enough. Thanks for the comment. I have incorporated it into the draft above.

I found the TPS calibration off by 45 mv. Starting from Jeff from Ohio's procedure, I developed a procedure summary. My goal was to eliminate iterative interdependent adjustments and the effects of any backlash in the connecting rod. My Draft Procedure Summary: First make sure the TPS is calibrated to 150 mv at fully closed as follows: disconnect the connecting rod, back off the right throttle idle screw and choke cam (make sure the choke cable permits full retraction of the cam (it didn't on my bike), then loosen the TPS clamp screws and rotate if needed. + - 5 mv can be obtained with a little effort. Next, close the bypasses, keep the right throttle idle screw backed off to put the connecting rod in tension, removing any backlash, and balance the throttles at idle using the connecting rod adjustment. Screw in the left throttle idle screw if the idle is too low to maintain. Do not use the choke for this purpose, because that would put the connecting rod in compression, introducing backlash. Now adjust the left idle screw for a TPS reading of .518 volts. + - .005 (corresponding to 3.4 degrees physical opening) can be obtained with a little effort. (Some riders have been known to also subsequently physically readjust the TPS (not the idle screw) to lean or richen the entire throttle range. However, loosening its screws and offsetting the TPS to a higher voltage, e.g. .539, will fool the ECU into adding more fuel, but it will also fool the ignition timing table.) Next open the bypasses to obtain the idle RPM at 1100 to 1200 while maintaining balance. Bypasses should be open 1/2 turn or more. If not, back off the idle screw to reduce the TPS in steps of 15 mv and open the bypasses to compensate until they are opened 1/2 turn or more. Check balance at midrange RPM as follows: A When checking balance at cruise RPM, make any fine correction needed using the connecting rod adjustment, then: B. Check balance at idle RPM. If OK, done, if not, rebalance at idle using the air bypass screws, and go back to step A. Option: Adjust the idle mixture trim potentiometer under the label of the computer for best idle quality, or use a gas analyzer if available. However, according to Guzzijack, "not an option on the V11Sport as it uses the 15M ECU - manual adjustment of the idle mixture potentiometer is only applicable to bikes with the P7/P8 or 16M ECUs - 15M idle mixture adjust is only possible via factory or aftermarket software." Once this procedure is completely successfully, in the future, minor changes in idle speed can be made simply by adjusting the left throttle idle screw. Since the throttle plates have been balanced, backlash between them has been eliminated, and bypasses have been properly adjusted to maintain balance at idle, these should be stable for many miles. Comments, anyone?

Do you really mean 4.85 volts at WOT?

MJ signifies Metal Jacket. An added factor of safety. Is sounds like you have no clearance problem.

Good idea, docc. Here's another procedure from the How To section, which seems to be technically thorough. However, note that the "My comments" are my personal edits, for my own file. I would like to see a response to these comments, and any superseding understanding of Jeff's comments with the result being a comprehensive, thorough, anc accurate procedure/explanation. Jeff in Ohio, April 13, 2004 “How to Balance the Throttle Bodies, with pictures, even”, in the How To section allow me to offer these comments. the air bleeds are not there to adjust the idle mixture, that is what the CO trimmer is for in the factory software. Idle Mixture Screw: This is located in the computer under the rubber plug, which is covered by the Moto Guzzi labeled decal. It's a tiny screw on a trim potentiometer; use an eyeglass screwdriver. The full range of adjustment is 270 degrees and clockwise is leaner, CCW is richer. The air bleeds are to be used for idle speed adjustments. A more proper procedure is to: 1. set TPS with everything backed off and disconnected (My comment: this means with the right throttle butterfly closed, idle screw, connecting rod and choke cam backed off) to the correct 150mv value 2. balance throttlebodies using the throttle stop screws with the air bleeds screwed in and the linkage unhooked so that the TPS reads the correct value as indicated in the service manual (3.4 deg +/- .2 deg, roughly 500-525mv) This is so the ECU is now set up so it knows the throttle plates are in the correct position for idle so all the mapping vs. throttle angle works out correctly. Your idle at this point will probably be be BELOW 1000 rpm and rather rough. (My comment: An alternative is to first balance the butterflies with the air bleeds screwed in, but then set the airbleeds to ½ turn open to raise the idle speed to 1100 RPM and check the TPS reading.) 3. open airbleeds and use them to balance to achieve the final appropriate idle speed of around 1100 rpm. Your idle should have smoothed out now. The factory manual goes out of its way to state the airbleed screws are there to set your idle speed. You will find that your airbleeds will end up being around 1/2 turn open as stated in the factory manual. 4. Adjust the linkage so that it can be reassembled without having to open one of the throttlebodies more than the other - that is, the socket on the link should drop back on the ball without having to move anything. 5. NOW rev your bike up and synch using the white knob. You might find that of you took great care in step 4, that the white knob has to be turned very little if any at all. 6. NOW use the factory software and a CO meter to set the correct idle mixture. In a pinch without a CO meter, you can set the trim like a mixture screw on a carb by adjusting it up and down to achieve the best quality of idle. That is why the software is needed - it is used to set the idle mix, NOT the airbleeds.

It's really due to the dedication of people like Greg Field, Pete Roper, dlaing, Ratchethack, and a few others. Another positive factor is that in this forum, people avoid creating a new thread whenever they wish to say something. That provides a convenient way to get a thorough response on an issue, and makes it easier to get the whole story. Two reasons why I personally keep track and stay involved. I believe Moto Guzzi is far better off as a result.