1985 Limited Edition 2022 Work Period

[Rednaxs60]

If I were to have the cylinder heads refurbished again, I would be taking a shim measurement before any cylinder head work and one after. This would give an indication whether a shim adjustment may be needed. Will be doing a shim measurement on the 1200 carcass engine I'm putting back together.

Regarding this 1200 carcass engine, have honed the two worst cylinders and the cylinder surface is not bad, but not pristine. Number 2 cylinder is pretty good, but number 4 cylinder - well nothings perfect. Going to go with this as I'm fairly certain that there are engines out there that operate just fine with a lot less love put into the cylinders.

Going to ride the bike with the rebuilt engine for a while and if all goes well, no engine change. Be putting the 1200 carcass engine cases together, tape off the cylinders and put in the crawl space. Nice and dry there.

Have found two '85 Limited Edition FI models here, one on the lower mainland, and one in town here. Asking price is not bad, but will monitor. Have a soft spot for these bikes, but no room to store.

 

[Rednaxs60]

More thoughts on the work I've done. Took the bike out for a road test, not too bad a ride, but still felt a stumble/misfire at low RPM. Just before I returned, had an annoying error code, misfire and then the code went away. Changed out the TPS for one I know is good, road test and all seems to be well, but still had that stumble/misfire at low RPM. The engine was extremely smooth at speed.

I remember noticing that the engine sound was different on the first start after the rebuild, then it returned to what I was used to. Never paid it any mind, but in hindsight, it was telling me something. I mentioned in an earlier post that #2 cylinder spark was weak. Again never paid it no never mind.

#1 and #2 cylinder use the same coil. #1 cylinder will cause a significant RPM change when the plug boot is removed, #2 very little RPM change. Not going to chase the coil aspect regarding change sides and such.

Going to look at the stumble/misfire from the ignition circuit. Approximately 12 VDC in, out to the spark igniters that are controlled by the ECU. The 12 VDC in to the coil is a common wire between the left and right coils so the 12 VDC signal to the right coil should be good, and is because #1 cylinder fires well.

Have the coils from the 1200 carcass that I brought back from Ontario. Notice that the coils are different. The coils installed have no polarity markings, the carcass coils do. The Supplement for the bike indicates that polarity is not an issue, think this is true as the left coil functions well.

To test my thoughts, going to make up a coil, leads and boots, disconnect the right coil, connect the test coil into the circuit and test the engine firing. Easier to do this before removing the installed coils, not easy to get at.

I had changed the 12 VDC supply to the coils early on in my ownership. I disconnected the original 12 VDC supply as it shares power with several components. The new wire was a true 12 VDC supply, not sharing power with any other component(s). Will check the power on the OEM circuit first.

The coils from the 1200 carcass engine are DW82-TR1 with polarity markings:


Spec out at 3.5 Ohms primary resistance - manual indicates 2.7 +/- 0.3 Ohms. Secondary resistance at the coil is 14.3/14.1 Ohms, will check again once the test circuit is together. Secondary resistance with wires and boots is supposed to be in the 24 +/- 3.9 Ohm range. Secondary resistance without the boots attached is supposed to be in the 19 +/- 2.7 Ohm range.

More to follow.

 

[OldWing SEI]

I had a similar experience with the coils, I used a flashlight, to test the firing and there were some dropouts. The measuring of the primary and secondary contacts was ok. After the change of the coil, everything was fine. You never know what happenes inside the coils, when they warm up while operating. Good Luck

 

[Rednaxs60]

Checked the Gr/Gl sensor air gaps as well. Adjusted the Gr sensor air gap, not out much but something to ensure is correct.

Testing the coils for primary and secondary resistance. Have three sets, one installed, 1200 carcass set and an aftermarket offshore set. The installed and carcass sets are the same DW82-TR1with polarity markings. The aftermarket have no polarity markings.

Checked the primary and secondary windings. The installed and 1200 carcass coils are practically the same, the aftermarket are not close. Primary resistance around 3.5 Ohms, secondary approximately 14.5 Ohms - no plug wires attached.

Contacted RMStator in Quebec. A small company that has coils, regulator/rectifiers, stators and such. It has new coils for the 1200 - $43.00 each with polarity markings, primary resistance 3.2 Ohms. 15% off if you buy two. This company has stators for the carb models but not the FI models; however, does rewind stators.

The engine operates best with the coils from the 1200 carcass, but there is still a slight miss. The 1200 carcass coils have the engine idle fluctuate between 940 and 980 RPM in 20 RPM increments. Thinking the digital readout is too precise, but the analogue readout is not. The installed coils (original) idles the engine about 100 RPM higher, but has that slight miss as well.

The original and 1200 caracss coils use the same new plug wires and new plugs. The engine sound when plug wires are pulled is more consistent with the 1200 carcass coils. Testing with the original coils, #2 cylinder is the weakest of the four when plug wires pulled.

When I balanced the cylinder banks, the vacuum gauge indicates 8-9 in vacuum. This is in the red zone just shy of good. The vacuum gauge indicates that if the engine vacuum is in this range, the valve timing could be off. Wondering if one tooth could be affecting the right cylinder head valve timing. Will use the right cylinder back as the guide for checking the timing. T1 mark on the flywheel will be close no matter what.

Timing setup will be next on the agenda. Everything is so close.

 

[pidjones]

I seem to remember in the kOhms region for secondary resistance.

 

[Rednaxs60]

You are correct. Should have mentioned 14.5 kOhms.

Would have been easier to check the timing marks when I had the air chamber out, but have to do one thing at a time or will never be able to isolate the issue. This is on the agenda for this weekend.

 

[Rednaxs60]

Today was a good work day. Front fairing off to have better access to steering and wiring. Checked the Torque on the steering column - all's good.

Found some small wiring issues with some of the connectors I have installed. New pins and good to go. Will finish a couple tomorrow.

Checked the engine timing. Flywheel mark at T1 is as per OEM manual, and the timing pulleys indicating "UP", all is well again. Here are the pics of the left/right timing pulleys. Don't think I can be any closer to exact timing:

Since I had the timing covers off and have a set of the cylinder head covers from the 1200 carcass engine for comparison, checked the timing marks and these are the same. The arrow for the right side timing mark indicates where the cylinder head cover timing mark is, left side is easy to see. Right side is damn near spot on.

Will get the front buttoned up, coolant in and the wiring issues repaired tomorrow. Will use the coils from the 1200 carcass engine as these coils are the most stable of the two sets.

Have one more TPS ready for install. This will be on my troubleshooting list. Getting good at changing the TPS out and calibrating. Will pick the best of the three to use for road test.

Have the Ns sensor from the 1200 carcass. It's an OEM original. Will take resistance readings and check against what I have installed. The Ns sensor installed is the harness from a 1986 Aspencade the uses two sensors as PG sensors. I have the external connector split so I can use one or the other sensor. The '85/'86 FI models can use a sensor in the upper or lower position. May change but it will depend on access.

I am just about out of items to verify correct. Once I have the engine started and warmed up, the last issue I can think of is maybe a weak ECU. Have two spares, I know bit of a hog, but one was purchased as a spare, the other came with the 1200 carcass. Will change the ECU to determine if It could be an issue, probably not, but need to rule it out.

 

[Rednaxs60]

The time and energy I have spent trying to track down the idle issue with the engine does give credence and a good defence for the motorcycle shops to not want to work on older motorcycles. Time, and a good plan to track down an issue is not inexpensive. Then add the cost to source a part, purchase and install. The issue with sourcing the part, if it's an old, used part, it's an old, used part.

The benefit of what I am doing is learning more about the '85 Limited Edition FI system. It's more agricultural than the 1800 FI system, but this is a good thing. The more intricate the system, the more can go wrong and diagnosing an issue is compounded as well.

I do feel a bit like the technicians of today in that the only way to diagnose an FI fault is to change out part(s) - need to determine your own diagnostic plan, but the manual does give guidance in how to check the part(s) to determine if the part(s) meet the OEM requirement.

Having mentioned the above, will continue my quest for the Holy Grail of the '85 Gold Wing FI system.

 

[Rednaxs60]

Did some additional research from a while back in 2017. I was browsing the CX500 forum and found a forum thread on replacing the PB sensors with Suzuki inlet air pressure (IAP) sensor as an alternative for the Honda PB sensors. These are being used on the CX500T and CX650T bikes with good success. The part is:

Brand: DENSO
Type number: 100798-5630 Suzuki ordering number 15620-35F00
Suzuki description: Sensor Boost, IAP (inlet air pressure) sensor

I did some tests on these Suzuki IAP sensors and compared the readings with the Honda OEM PB sensors. The results were reasonably close and linear. My test apparatus was rudimentary, so the readings were close enough.

To do this test, the power source for this was 3 - AA batteries in series giving me 4.8 VDC. I hooked up a test circuit with multimeter. Here are my readings, read in 3 columns - inches of Hg/Suzuki sensor - VDC/Honda OEM PB sensor - VDC:

0 inch of Hg/3.45/3.63
5 inch of Hg/3.1/3.14
10 inch of Hg/2.65/2.59
15 inch of Hg/2.18/2.0
20 inch of Hg/1.73/1.43
25 inch of Hg/1.26/0.88

I also checked the vacuum at the PB sensors and at approximately 3000 RPM the vacuum to the sensors is 10 to 12 inches of HG and remains steady at these vacuum values as RPM increases. At 12" of Hg - Suzuki sensor - 2.46 VDC.

It was mentioned on the CX500 forum that the PB sensors influence the engine operation up to approximately 3000 RPM, after which the PB sensors are no longer in play. This comment elicited a few responses where the owners were experiencing idle and low engine operation RPM stumbles, and that when the Honda PB sensors were changed out for the Suzuki IAP sensors, the low RPM stumble went away. There were posts regarding the Honda PB connectors, and new connectors with the Suzuki IAP sensors got rid of the idle and low RPM engine operation stumble.

I had a set of these installed from 2018 until January this year, and the Suzuki sensors worked well. Changed these out for the Honda OEM PB sensors from the 1200 carcass. Will be going back to the Suzuki IAP sensors. Will make a new connector set and may splice into the wiring harness.

A fellow on the CX500 forum took one of the Honda OEM PB sensors apart and found that the manufacturing of this part was very rudimentary. One of the issues that was found is that the internal construction/connections was less than stellar (they took one apart) and since the connections were not soldered, the internal connections would come apart such that vibration would cause the PB sensor to fail. This is a good hit/miss scenario when troubleshooting.

This is the Suzuki IAP sensor connector diagram:

I believe I posted this information back in 2017, but it has been 5 years and a repost is always good. Another piece of the puzzle to explore.

 

[Rednaxs60]

Went back into another forum and found a thread I started way back. Found this web site address and it is a good explanation of the MAP sensor: Manifold Absolute Pressure MAP Sensors. A good read for those with n '85/'86 FI Gold Wing.

 

[Rednaxs60]

Read the above web site again, been a while, and like the information presented and how it is presented. As mentioned will be installing the Suzuki IAP sensors when I start to reassemble the bike. Have checked the Ns (crank) sensor as installed - resistance is in the test range. Checked the Gr/Gl sensors - on the rear of the right cylinder head - resistance is in the test range.

Did some additional digging and found articles regarding the reed valves that are used. These are generally the last item that is checked, and in my case I can understand because of the location and there are no test points. Will have to remove the air chamber to test, or to install test points.

The inlet air control system is a passive air in system. Air is drawn in from the air chamber through an inlet air control valve (IAC valve) that has an internal bimetal strip that is powered from the same circuit as the fuel pump. Fuel pump on, power goes to the IAC valve.

To get my thoughts in order, did a drawing of the 4 stroke cycle to relate it to the reed valve working(s). Intake stroke - intake valve open, reed valve is caused to open and air flows into the cylinder. Compression - intake/exhaust valves closed, reed valve is closed, no air flow into the cylinder. Power - intake/exhaust valves closed, reed valve is closed, no air flow into the cylinder. Exhaust - exhaust valve open/intake valve closed, reed valve is closed, no air flow into the cylinder.

The reed valve for each cylinder bank is cross connected with the adjoining cylinder at the injector holder. A vacuum hose goes from this cross connection up to the respective PB sensor. I have replaced all the vacuum hoses so none are blocked or cracked.

When I balance the cylinder banks, best vacuum has been in the 8 to 9 inch Hg range. The vacuum gauge(s) indicate that this is low and could be caused by a valve timing issue, or vacuum leak(s). The article posted above indicates that engine vacuum at idle should be well over 10 inches of Hg. The timing is spot on so I'm ruling that one out. There are no vacuum leaks that I can see, nor from an o-ring perspective as I have used engine quick start to spray all connections that are visible.

I mentioned in another thread a while back that the '85 FI system ECU uses the Speed Density and Alpha-N mapping to control fuel and ignition timing with a MAP - manifold absolute air pressure sensor. The MAP sensor is different from a MAF - mass airflow sensor in that the ECU uses the MAP sensor in conjunction with the other system sensors and "estimates" the air flow instead of measuring airflow directly with a MAF sensor. A MAP sensor is less affected by vacuum leaks.

Up to approximately 3000 RPM the FI system uses a Speed Density mapping to control the engine. Speed density mapping uses the PB (MAP) sensors with engine RPM, throttle position, coolant temperature and ambient air temperature to estimate how much air is entering the engine and with this, the ECU controls the amount of fuel entering the engine and the engine timing. Once pats the 3000 RPM range, the PB sensor signal to the ECU is a constant, and is not used by the ECU in the Alpha-N mode. The two key elements in the Alpha-N mode are throttle position and engine RPM as the ambient air temp should be consistent, as should the coolant temperature. These latter two inputs can change and as such, are always considered.

I have digressed a bit, good refresher.

Still need to think about the reed valve, but will get some test points installed.

Checked a few other threads regarding engine vacuum, and from the videos that have been posted, the vacuum appears to be north of 10 in Hg. Have to get mine out of the red zone.

 

[Dusterdude]

Can you delete the reed valves like i did on my fi vulcan?

 

[Rednaxs60]

Can you delete the reed valves like i did on my fi vulcan?

This depends on if we are speaking the same language. Did you remove the PAIR system, or did you remove the inlet air system for combustion? The PAIR system is to inject air into the exhaust to add more air into the exhaust system to ensure that almost no unburnt gases get out the exhaust - an emission standard requirement.

The inlet air system I am dealing with is allowing combustion air into the cylinders on start, idle and when the throttle plates are closed to decelerate. Honda found on the '82/'83 turbo FI models and the subsequent '85/'86 FI models that without this extra air, the engine would starve for combustion air and all sorts of neat things would happen.

The difference between the '85 FI IAC system and the newer IAC systems is the '85/'86 FI IAC system is passive, the newer systems are an active system that use a servo motor controlled by the ECU to control the IAC valve, instead of engine vacuum to draw air through a reed valve.

The best I could hope for is to find NOS reed valve assemblies, dreaming in technicolour, or replace the reed valves and IAC valve with a servo activated IAC valve. Don't know if I could integrate this type of system into the '85 FI system.

 

[Dusterdude]

Yes,honda calls it a pair system,does the same thing

 

[Rednaxs60]

This is a modern invention for environmental regulation and emissions requirements. Did not exist, or if it did, was not incorporated into the '85/'86 FI models.

 

[Rednaxs60]

Need to update my progress so I don't forget what I have done and what I viewed. Took the air chamber out yesterday afternoon/evening to get at the reed valve assemblies. There are no parts available if you had to repair a reed valve assembly, just used parts and you would probably have to purchase a complete air chamber assembly to get the used reed valve assembly.

The reed valves are very easy to work on. Take out, remove the reed valve cover, remove two screws to get at the reed petal itself. The reed is a very thin metal strip that goes in one way only. Modern day reed valves are generally fibreglass or carbon fibre.

It is held on with the same 2 screws as the reed valve stop plate:


There was some carbon deposit around the reed sealing face. You can see the blackened portion in the above photo. The sealing face of the four reed petals was coated with a carbon/oil film deposit as well. The carbon/oil film on the sealing face indicates to me that there has been significant blow by in this engine form some time before rebuild because air is drawn into the IAC system from the air chamber that the engine vents to.

I did a rudimentary test of the reed valve assemblies when I first had the reed valve assembly covers off. Blew into the reed valve assembly and listened for air to flow. The reed petals were sticking because you could feel a pressure build up - like blowing up a ballon, then the reed petal would open and the pressure would go away.

No need for comments on this part of the test procedure. I then sucked on the air inlet tube to determine how the reed petal(s) were sealing. The reed petals seem to be sealing very well. I removed the reed petals, inverted these and noticed that the reed petal was proud of the reed valve assembly sealing face. Where the reed valve stop plate and reed petal attach to the red valve assembly sealing face, the reed petal and reed valve stop plate have one side chamfered. This ensures that you do not install the reed petals incorrectly. Have read that a slight, very slight back flow of air past the reed petal is normal.

Cleaned up the reed valve assembly sealing face(s) and the reed petals:


Reassembled the reed valve assemblies, used Honda Bond 4 off the mating surface of the reed valve assembly cover to ensure a good seal. Will be installing these on the air chamber today as well as installing the air chamber.

The throttle plates are clean, air passages proved clear.

Having finished this part of the investigation into the low RPM/idle stumble, not much left except the ECU.

Have tested for resistance IAW the OEM Supplement: Tw, T1, Gr/Gl, Ns sensors - all in spec. Injectors have been cleaned, flow tested and checked for impedance. Fuel pressure has been checked for static and dynamic pressures, both good. Engine compression good, in the 160 PSI range. TPS is calibrated. Engine cylinder banks balanced. Coils tested for primary and secondary resistance - in spec. New plug wires will be used, and new plugs. Plug cap(s) resistors checked for resistance - good. Engine timing spot on. may look at the valve shimming once more, but with the engine compression being good, shouldn't need to.

Will do a cylinder balance once more. Will have a second vacuum test point near the PB sensors to do some cross checking.

 

[Rednaxs60]

Yes,honda calls it a pair system,does the same thing

Did additional looking. The 49 state and CA '85/'86 FI models are different from the Canadian versions. These have a secondary air system to meet the state environmental legislation, the Canadian version(s) do not. The 49 state and CA FI models have the IAC system for additional combustion air.

The air chamber vacuum and air supply passages in the throttle bodies are different. Checked the air chamber from my bike and the throttle body throats do not have any additional ports for air in/out (?). Have sealed off the potential secondary air passages to mitigate any issues because of these.

The cylinder heads are different. The heads for the 49 state and CA FI models have secondary air supply system ports in the top of the head to accept the secondary air supply tubes, the Canadian version(s) do not:

This is a pic of the Canadian cylinder head. Notice the absence of the secondary air supply system ports:


I'm thinking that the secondary air supply system adds air to the exhaust side of the cylinder head, in essence the equivalent of the modern day PAIR system.

 

[Dusterdude]

Cool

 

[Rednaxs60]

Very cool. Learn something everyday. Was wondering when I would make a statement about the difference, not that I ever do that.

Was at it again today. Have the bike buttoned up to a test platform state. The Suzuki IAP sensors installed, using the original coils - tested all four and chose the ones that tested the best, happen to be the original coils.

Started the engine, let it run fuel through the system. Connected the vacuum gauges to the cylinder banks, and to the connection at the PB sensors.

The idle is much improved, didn't hear that annoying "stumble" but that could be a ruse . The cylinder vacuum is better. The left side has the best, be easier to balance the cylinder banks once the front fairing is back on and I have some gauges to watch.

When I pull the plug caps on the right side, there is a definite engine RPM change, not so much on the left - more subtle but does happen. I will check the connections tomorrow before I start to put the pieces back in place.

Will change the ECU after everything is back together. Last piece of the mystery.

 

[Rednaxs60]

Intend to swap the PB sensors today to determine if these were an issue.

Mentioned the vacuum was better, going to check the injector holder(s) o-rings - the ones between the head and injector holder, as these o-rings sometimes come out of the o-ring groove, just happens. Will be able to see with the small borescope through the injector hole.

The ECU change will be this morning as well.

Curious as to why the difference in the RPM change from the other day when I was testing the two coil packs.