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Discussion Starter · #1 ·
Just got a CX 500 T that had been in storage, with the gas on, for five years. On starting the engine idles rough and does not like to take the throttle. I have computer lights on W-0-3, with the Fuel System light also. I do not have a shop manual. Does anyone know what the code points to?

Injectors have been cleaned, fuel pump replaced, plugs replaced, wastegate check for sticking, fuel filter installed, and fuel lines replaced.
 

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Smith,

If I understand you correctly, then lights W,0, and 3 are on, right? If that is the case, then your Engine Speed Sensor is shorted, most likely one of the two coils is bad. Good news: it's an easy fix, without having to find a discontinued part from Honda, nor replace it. I have a long detailed article from the old forum where I show you how to repair and rebuild it. You should first test it to make sure. I have a 500 and 650 manual and can probably FAX you copies of the procedure on testing and removing it (it is located inside the water pump housing, and can be removed with the engine still in the frame). In a nutshell, there are two coils on the plate, which trigger timing and injection. If one is out of range, shorted or open, the CX500T will run, but will not throttle up very well. Your bike seems to have these symptoms. If someone has a scanned copy of the service manual that they can e-mail to you, that might work better. But I will be more than happy to FAX you the pages you need to get you started on testing and removal. I can e-mail pic's that I have that show the sensor repairs and the assembly.

My email is hondacxt at yahoo dot com (spelling this way helps prevents spammers)..........Nothing to worry about brother: YOU CAN DO THIS..........
 

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Smith:

Here is the procedure, which I posted on the old forum:





The repair was very simple. I removed the sensor mounting plate from the water pump housing (about an hours work). You will notice two pickup coils on the plate at about the 8 o'clock and 4 o'clock position. One pickup has blue and blue with white leads, the other has yellow and yellow with white leads. No need to disturb the magnet and mounting tang. The pickup coils slide right off the metal tang with just a little effort. Try not to bend the tang, as it could change the air gap spec. The Nippondenso coil is the part that fails anyway, not the magnet. The Denso coils are nothing more than a sealed coil of wire, that when the reluctor on the crank/water pump shaft turns, it induces an AC voltage that the pickup coil sends to the ECM. See for yourself; with the plate on a workbench, have a multimeter hooked up to read AC volts on one of the coils two leads, then simply place a screwdriver near the coil. It should suddenly read about .013- .025 AC volts approx. that means it is working and sending this signal to the ECM for injection and ignition triggering.

The Denso coils on out bikes are IDENTICAL to the crank position sensor/ignition pickup coils on Toyota, Honda and Mazda distributors with fuel injection. Same idea, to trigger injection and ignition. The coil specs are the same also; no more than 250 ohms resistance in the coil. Of the dozen or so I checked at the junkyard with my multimeter, they were all around 150-170 ohms, well within specs. I simply stripped the ends of the wires and joined them to the old coils leads with solder and insulated with heat shrink wrap from Radio Shack. No butt or crimp connectors! Tested it for continuity to make sure there was a good solder joint and reinstalled the water pump housing and then onto the bike. Fired right up with no fault code! Rode it for a few hours with no problems. I actually took three sensors from the junkyard as spares, since the other coil probably may fail soon anyway. I took pictures of what I did. Another lesson here is that the CX500T will run poorly if only one coil fails; IT NEEDS THEM BOTH!!! It may be different on the CX650T, as a few other posts have pointed out. After this little venture, I am convinced that any obsolete sensor on our bikes (P1,Pb,Pign, ect) can probably be repaired with a little brainstorming and ingenuity.
 

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Discussion Starter · #4 ·
I found the Turbo Manual download after I posted. Yes it does point to the speed sensor. After omh checking the the unit one pickup did check open. Do you know if this pickup can be aquired new, at the auto supply?
 

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Yes,

you can buy them new - I picked up two last year from the US - still to be installed.

I have the same problem, this was after I bought the bike and found it was not running correctly.



Also read your writeup with the pictures HomerRod, nicely done.



I find getting access to the area is not easy, so do you have any hints on doing this, or what needs to be removed for better access??



thanks
 

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Discussion Starter · #7 ·
Thanks for the info. I checked at the auto parts store today and they can order the sensors (PN LX 579) for $49.00 each. High price but at least I can get them. The bike is apart with the water pump housing ready to come off (outer pump plate removed). I will continue to disassemble the bike today. I hope to not damage any components in this process. I will check on the price of the BWD, maybe less expensive.



Update: Got the water pump and speed sensor housing removed. Looks like the water pump shaft seal has been leaking-the speed sensor cavity is very rusted. I have the speed sensor plate screws soaking in break free at this time. When the speed sense/water pump inner plate was removed the drive to the camshaft end did not seperate and the roll pin connection, it was so rusted the the drive on the end of the cam shaft came off with removal. This drive assembly is not indexed to the camshaft end. The drive can go on in any of 360 deg., it will still sense speed but it can rotate on the end of the camahaft. Any ideas?
 

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"Update: Got the water pump and speed sensor housing removed. Looks like the water pump shaft seal has been leaking-the speed sensor cavity is very rusted. I have the speed sensor plate screws soaking in break free at this time. When the speed sense/water pump inner plate was removed the drive to the camshaft end did not seperate and the roll pin connection, it was so rusted the the drive on the end of the cam shaft came off with removal. This drive assembly is not indexed to the camshaft end. The drive can go on in any of 360 deg., it will still sense speed but it can rotate on the end of the camahaft. Any ideas?"



The camshaft did not break, did it? As long as the camshaft is intact, and only the sensor rotor lobe pin rusted away, then you are OK.

The lobe is held in place by a solid pin and only aligns in the correct position. The pin goes into the cam first and the lobe then slips over the pin into the notched area on the lobe. If the pin is missing or rusted away, just get another pin at the local hardware store. You may have to trim or modify it, but I have done that myself because of a rusted out pin. No problem there. While you are in there, replace the water pump mechanical seal. You can buy one from Honda, pt# 19127-657-023, about $46. Or you can use the Yamaha seal (as I have done several times), Yamaha pt# 11H-12438-10-00, about $18 as of two years ago. It fits perfectly, and may be easier to get.

BTW, can you do me a favor? While you have it disassembled, can you measure the impeller collar for me? It is the slip on collar that goes behind the sensor rotor lobe. I need the outside diameter and the overall length, inches or mm's are OK. I know this is an odd request, but last year when I was replacing the seal, I lost the collar, and made one from a bronze bushing at the hardware store. I want to make sure it is within proper specs & size. Thanks!!!
 

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Discussion Starter · #9 ·
"Update: Got the water pump and speed sensor housing removed. Looks like the water pump shaft seal has been leaking-the speed sensor cavity is very rusted. I have the speed sensor plate screws soaking in break free at this time. When the speed sense/water pump inner plate was removed the drive to the camshaft end did not seperate and the roll pin connection, it was so rusted the the drive on the end of the cam shaft came off with removal. This drive assembly is not indexed to the camshaft end. The drive can go on in any of 360 deg., it will still sense speed but it can rotate on the end of the camahaft. Any ideas?"



The camshaft did not break, did it? As long as the camshaft is intact, and only the sensor rotor lobe pin rusted away, then you are OK.

The lobe is held in place by a solid pin and only aligns in the correct position. The pin goes into the cam first and the lobe then slips over the pin into the notched area on the lobe. If the pin is missing or rusted away, just get another pin at the local hardware store. You may have to trim or modify it, but I have done that myself because of a rusted out pin. No problem there. While you are in there, replace the water pump mechanical seal. You can buy one from Honda, pt# 19127-657-023, about $46. Or you can use the Yamaha seal (as I have done several times), Yamaha pt# 11H-12438-10-00, about $18 as of two years ago. It fits perfectly, and may be easier to get.

BTW, can you do me a favor? While you have it disassembled, can you measure the impeller collar for me? It is the slip on collar that goes behind the sensor rotor lobe. I need the outside diameter and the overall length, inches or mm's are OK. I know this is an odd request, but last year when I was replacing the seal, I lost the collar, and made one from a bronze bushing at the hardware store. I want to make sure it is within proper specs & size. Thanks!!!
 

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Discussion Starter · #10 ·
"Update: Got the water pump and speed sensor housing removed. Looks like the water pump shaft seal has been leaking-the speed sensor cavity is very rusted. I have the speed sensor plate screws soaking in break free at this time. When the speed sense/water pump inner plate was removed the drive to the camshaft end did not seperate and the roll pin connection, it was so rusted the the drive on the end of the cam shaft came off with removal. This drive assembly is not indexed to the camshaft end. The drive can go on in any of 360 deg., it will still sense speed but it can rotate on the end of the camahaft. Any ideas?"



The camshaft did not break, did it? As long as the camshaft is intact, and only the sensor rotor lobe pin rusted away, then you are OK.

The lobe is held in place by a solid pin and only aligns in the correct position. The pin goes into the cam first and the lobe then slips over the pin into the notched area on the lobe. If the pin is missing or rusted away, just get another pin at the local hardware store. You may have to trim or modify it, but I have done that myself because of a rusted out pin. No problem there. While you are in there, replace the water pump mechanical seal. You can buy one from Honda, pt# 19127-657-023, about $46. Or you can use the Yamaha seal (as I have done several times), Yamaha pt# 11H-12438-10-00, about $18 as of two years ago. It fits perfectly, and may be easier to get.

BTW, can you do me a favor? While you have it disassembled, can you measure the impeller collar for me? It is the slip on collar that goes behind the sensor rotor lobe. I need the outside diameter and the overall length, inches or mm's are OK. I know this is an odd request, but last year when I was replacing the seal, I lost the collar, and made one from a bronze bushing at the hardware store. I want to make sure it is within proper specs & size. Thanks!!!
 

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Discussion Starter · #11 ·
The aft end of the camshaft has a collar the goes over the camshaft (this is where the unit seperated on me) at this point the drive will go on the end of the camshaft in any of 360 deg, no index pin. The section of the speed sensor/water pump drive with the roll pin index is aft of this collar, and this is rusted together. Soaking in break free). I have not found anything in the MM that address this component. The seperated section is not broken (no sign of fracture metal) it is machined to fit over the camshaft, but does not index.



I will mic the section of the bushing that you need measurements for when I can break it free of rust. You have probally never seen the section of the camshaft drive past the camshaft engine oil seal, this is where the collar goes, it runs on the seal to the aft camshaft.
 

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I was lucky enough to get a spare motor and frame the other day - was told the motor was low mileage, and had plenty of compression - but has sat outside for 12 years under a tarp - I'm not having a go at the seller either here.



I bought it (not fully paid for yet either) as a source of spare parts for my bike which shows a lot of signs of being abused during its lifetime.



Stripped motor out of frame - gradually took some parts off - cleaned, packaged & labelled for future use. So I thought I would get to see how the sensors were on this motor - see attached link - then I discovered the motor has plenty of compression - turning from the front bolt with plugs in - it is really strong - takes two goes to get it past TDC leaning on my ratchet. but motor has a broken camshaft - not really expected or probably known by the seller either..



some photos to see how it was repaired (badly)..



http://s870.photobucket.com/albums/ab262/81custom/cx500Turbo/
 

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Discussion Starter · #13 ·
Thanks for the pictures. Where the camshaft end is broken off in the drive to the induction unit (where the speed sensors are), mine has just pulled the machined end off the camshaft itself. Mine appears to be repairable. I'm thinking a good cleaning and then reinstalling the end with red locktite. The only drag on the entire unit is the water pump. I am also thinking the sensors do not have to be indexed to the engine, just rotated to operate properly. The speed sensor mounting plate has the angle of firing built into the mount, all the two sensor do it sense the camshaft speed and send this information to the computer. Speed is Speed? Am I all wet?
 

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There is a broken cam picture on photobucket. Is that your picture? If so, I wish I had better news for you. The cam will need replacement, which means removing the motor. You may be able to repair it in place, by splicing a sleeve over it and then pinning in place. Another option is to join it back together with JB Weld, and only if you join the two pieces with a threaded stud first (don't rely on just the JB Weld). If you can slowly drill into the cam pieces and then thread the stud in until they seat together, with the JB Weld in between. It may not even be possible, since the cam is a casting and may be internally brittle, but the outside is probably case hardened. The better repair is cam replacement.
 

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Discussion Starter · #15 ·
I found a mark on the cam piece where it came off. I have turned the motor to F1 on the right cly and checked the placement of the inductor coil, it appears to be in the correct location. The aft end that came off is a press fit, (as installed at the factory) the only drag on this unit is the water pump. I plan to install the seperated section with red locktite. The seal was a real problem, I have one coming from Pervis bearing $7.50. The Honda shop showed on interest in even looking for a match in their stock. So much for keeping the old stock running from Honda. All the parts should be in hand next week.
 

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Most CX camshafts have a pin to locate that rear end of the camshaft, even though the naturally aspirated camshafts have no need of accurate angular position, being only there to drive the water pump impeller.

The turbo NEEDS an accurate angular alignment of that rear portion, because the Ne sensor has to generate an accurately timed pulse to tell the ECU how the motor is accelerating/decelerating.

WE have found out - by much trial and error - that even the Ne sensor coils MUST be connected with the correct polarity, to give the correct wave-front to the ECU.

Your two camshaft bits should show evidence of an assembly/location pin.
 

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Discussion Starter · #17 ·
I have installed the camshaft end in line with the marks made when it was removed, lets hope this is the correct placement. The camshaft water pump drive end on my bike was not pined. I installe dthe camshaft end with red locktite and it has cured for two days. I now have all the parts in hand to put the bike back together. The sensors have been replaced and wired properly as per a post in this section. Lets hope it runs or I will have a pretty good parts bike.
 

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Let us know how you make out. I thought my sensors were wired in correctly, per posts on forum etc. I had a no start condition that was resolved by carefully troubleshooting the wiring connector for the speed sensors by swapping things until I had a combination that worked. Hopefully you photo'd and or wrote down what color wires you connected to what colors, etc.
 
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