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05-10-2009, 9:47 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 83 cx650T sputtering/popping/bogging below 4000 I have a 83 650TC and I've had it for two years now. I am hoping that I can pick someones brain to try and sort a problem out that has been a real pain. My bike is in very good shape with 75000 kilometers on it (46000miles) Right from the time I bought it it has had a popping/sputtering/bogging at lower rpms(below 4000) and sometimes above 4000. Even idling it will miss frequently. The turbo works fine and when it gets past the 4000 mark it goes like shit with only a few misses as it goes to 7-8000rpms. Heres what I've checked and confirmed to be good or made no difference. -fuel system is spotless -I've changed coils with my 84 CX650E - changed spark igniters with same bike -removed spark plug resistors -changed spark plugs -ran a good fuel system cleaner through it. -checked orifices on throttle body-clean - all related hoses good condition -changed fuel pump and injectors( I have original spares) -no error codes on CPU - Compression above 140 on both and within 10% of eachother -All electrical connectors appear to be in good repair and properly connected -Checked engine coolant, air temp, cranshaft angle, and engine speed sensors. All check good according to the shop manual. -When you turn the key on the fuel pump runs for the 2-3 seconds as per spec. Fuel pessure has NOT been confirmed. -Injectors click when throttle opened fast with ignition ON. -Air filter clean. -Changed TPS with one from a 500(supposed to be interchangeable according to the local Honda shop) - It has a new battery. What I was going to check next is the reed valves in the intake for cracks or broken sections, then throttle butterflies for syncronization and also intake leaks on the throttle body itself. My first suspicion was the engine coolant sensor, as when the engine is cold it will start faster and, in neutral, will rev from idle up to 3-4000 almost flawlessly.(when hot it cranks quite a few times before it lites and when it does it has to be throttled for a few seconds before it will idle more smoothly), After the engine starts to get warm the problem raises it's ugly head. After noticing this it put a 0-2500 ohm manually adjustable potentiometer in place of the sensor outside of the motor that can be adjusted by hand. The only way I can get the bike to run halfway good is to leave it at 2500 ohms all the time simulating a cold engine. (The only real difference is that the bad bogging disappears and the popping/backfire goes away also) If I back it down to 2-400 ohms as per manual when the engine is hot the bike starts to POP, sputter badly and bog badly. It will still perform above 4000 after giving it lots of throttle to get past these symptoms. Now about 2% of the time the engine will go up through the revs and gears pretty much flawlessly but at the next light it will go back to the same issues. If it was the CPU then the symptoms would be there 100% of the time. In my case there are small windows of smooth performance which leads me to think that it's something mechanical or a sensor. I have only had one error code a few times from the CPU and it's saying the Crankshaft angle sensor, but it seemed to check out according to the manual. This code appeared with the potentiometer set 2500 ohms. Now I have read lots of post about the engine speed sensors failing and being rebuilt/changed. Anyone have any dealings with the angle sensor. Any help anyone can give me would be very appreciated. Thanks for taking the time to read this and consider any remedies for my CXTC. Cheers Stephen    Report

05-12-2009, 6:54 PM showkey Joined on 03-02-2007 Northern IL Posts 70 Re: 83 cx650T sputtering/popping/bogging below 4000 You really covered most of the common problems. I think I would check fuel pressure, sounds lean and by fooling the coolant temp sensor you are forcing it richer by increasing injector duration to the "cold setting".. You could try fooling the fuel pressure regulator by disconnecting the vacume line, this forces the pressure to high limit all the time, that is assuming the pump and regulator is capable of putting full pressure and volume????? Back to checking fuel pressure, volume and fuel pressure regulator?        CX500T 1982 (3) Transalp 1989 GL1100 1983 XL250R 1987 NT650 1988 TRX250 1986 CT90 1972 C70 1981 XR250R 1994    Report

05-13-2009, 8:14 AM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 Thanks for your input. Fuel pressure or the regulator has been a thought of mine also. Although when I changed the fuel pump it didn't change a thing. The regulator has been something that I have wondered about. How do I determine if it's the regulator, and are there any still available? Once I disconnect the vacume line I'm assuming that I have to plug it with something while testing. What are the chances that the regulator is physically stuck? Thanks again Stephen    Report

05-13-2009, 3:04 PM George in Indiana Joined on 03-03-2006 Posts 954 Re: 83 cx650T sputtering/popping/bogging below 4000 You've hit just about everything it seems. Since you didn't list it, I'm gonna ask...is your valve lash set correctly? Try a leak down test yet? I've read threads in the past where regular CXs have had issues similar to yours when the valves were too loose or too tight. As the engine warmed up tolerances changed and the bike would act differently, but still crappy. If you set the lash, run the bike a while and check again, is the gap still the same? I've heard that the 650T has issues with cam lobe pitting and premature wear. Although unlikely, I wouldn't totally rule out the ECU either. Capacitors dry out causing tolerances to change as they warm up during use. If you could get a hold of a spare, it wouldn't hurt to try it. CX500 TURBO CX650 TURBO '04 GSX1300R Hayabusa    Report

05-14-2009, 9:08 AM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 I did set the valves about 3-4000Km(2000-2500 miles) ago They were very slightly out when I checked but I readjusted anyway. The cam doesn't show any signs of pitting that I can see. My 84E has had the gaps out but never worked like this, only a little noisy. The turbo pretty much works the same all the time lately. The smooter running at first start seems to be slipping away.    Report

05-14-2009, 12:29 PM TurboDan Joined on 03-06-2006 Griffin, GA Posts 92 Re: 83 cx650T sputtering/popping/bogging below 4000 Have you checked the resistances of the spark plug wires? The resistors in the spark plug boots go bad sometimes. Make sure the spark ignitor modules under the left side cover have clean and good electrical connections. Check you wiring harness for intermittant shorts or opens, especially the grounds. If you cannot locate problems with any of these items my experience has been the ECU is the culprit. The 650T has the ignition controls in the ECU while the 500T had a separate ignition controller mounted under the seat. The CXT has three fuel filters, one in the tank, the main filter, and the nylon cone where the large fuel hose connects to the fuel pump. There is a brass micro-screen at each injector inlet. Dan Topping Diesel Tech Program Coordinator Griffin Technical College Griffin, GA owner CXTC's Parts & Accessories, Inc    Report

05-14-2009, 1:08 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 In my original posting I said that I took the resistors out but what I forgot to mention is that I put bran new wires on it but it didn't do anything for the problem. The ignitors as per my first posting have been ruled out as I switched them out with my 84E as they are the same. As far as the wiring harness goes I have gone over that quite extensively with it being still in the bike. All connectors look good and the grounds have been confirmed as good. Short of going after a replacement CPU I would like to confirm if the fuel regulator is the problem or rule it out. I'm running out of things to check. Any advice on how to check the regulator?    Report

05-14-2009, 5:01 PM TurboDan Joined on 03-06-2006 Griffin, GA Posts 92 Re: 83 cx650T sputtering/popping/bogging below 4000 On the banjo bolt for the high pressure fuel line to fuel pump connection, there is a small bolt with an aluminum washer. This is the port to which you connect a fuel pressure gauge. It will indicate the fuel pressures you have at different operating conditions. The Honda CXT shop manual spells out the procedures. You can take the hose between the regulator and manifold and use a pressure/vacuum pistol to chnage the settings and watch for the appropriate changes in the fuel pressure. If you happen to need a regulator I can lay my hands on several. I also have several ECUs. Dan Topping Diesel Tech Program Coordinator Griffin Technical College Griffin, GA owner CXTC's Parts & Accessories, Inc    Report

05-14-2009, 8:18 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 Thanks I will give it a try and let you know. It will probably be a while before i get to it as we are in the middle of moving over the next week. Good to know there are still parts out there. How much for the reg. and ECU Thanks Stephen    Report

05-14-2009, 8:20 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 Also does the reg work on both vacume and positive pressures, and what are the values I should be putting it under? I guess it's probably in the shop manual right!! Stephen    Report

05-31-2009, 6:39 PM Don in Oz Joined on 03-10-2006 Melbourne, Australia Posts 546 Re: 83 cx650T sputtering/popping/bogging below 4000 Stephen, You should be using a range of pressures at least from + 18psi to -8psi to test the regulator.  This regulator is VERY difficult to alternate-source, owing to the large threaded end which screws into the fuel rail.  Many regulators that you think might do the trick are not rated for positive pressure to this limit, and they usually rupture the diaphragm on the first motor run-up on boost. Don. GL500I, CX500TC (2), CX500EC (2), 1982 CX500C. GL1000, 1976 CB550F, CT110 (2), XL125S (2), 1973 CB175K6. Kwaka Z250C1 (2). Suzuki GS450SX, DR250SJ, GS125ESD.    Report

05-31-2009, 8:03 PM showkey Joined on 03-02-2007 Northern IL Posts 70 Re: 83 cx650T sputtering/popping/bogging below 4000 I am confused I thought we were talking about fuel pump pressure that will be about 38 PSI and changing the vacume line attached to the pressure regulator will cause the fuel pressure to change. 18 to -8 are you talking about manifold pressure??? CX500T 1982 (3) Transalp 1989 GL1100 1983 XL250R 1987 NT650 1988 TRX250 1986 CT90 1972 C70 1981 XR250R 1994    Report

06-01-2009, 4:30 AM Don in Oz Joined on 03-10-2006 Melbourne, Australia Posts 546 Re: 83 cx650T sputtering/popping/bogging below 4000 The way you test the fuel-pressure regulator is to vary the manifold pressure inlet line over - say -8 to +18 psi - whilst supplying the fuel inlet port with petrol from an EFI fuel pump, being careful to allow the fuel outlet of the regulator easy dumping of the relieved fuel back to the supply tank.   The fuel pressure between the pump and the regulator ( the fuel "rail") should hold steady at 36psi for 0 psi (atmospheric pressure) at sea level, and should climb to 54 psi at +18  psi pressure into the manifold pressure inlet, and drop to 28 psi when -8 psi is applied to that manifold pressure inlet.   Your fuel pump MUST be capable of at least  80 psi static pressure for operating the bike at full boost, to be sure of getting the 54 psi you need for delivery of the necessary fuel flow. If your bike has a fully operational fuel system, it's easier to do all this with the bike's fuel system assembled on the bike - measure the fuel pressure at the point Dan says, and use a vacuum/pressure pump with gauge attached to the manifold pressure inlet tube to the regulator Don. GL500I, CX500TC (2), CX500EC (2), 1982 CX500C. GL1000, 1976 CB550F, CT110 (2), XL125S (2), 1973 CB175K6. Kwaka Z250C1 (2). Suzuki GS450SX, DR250SJ, GS125ESD.    Report

06-01-2009, 7:52 PM showkey Joined on 03-02-2007 Northern IL Posts 70 Re: 83 cx650T sputtering/popping/bogging below 4000 Ok...........thats a much better explanation, and very complete test more comprehensive than the shop manual test.  If a hand vacume-pressure pump is available he should be able "move the regulator" and watch the pressure gauge and get a close guess if the pump is OK.  I would guess if the pump was faulty the concern might be above 4000 RPM not below 4000.  CX500T 1982 (3) Transalp 1989 GL1100 1983 XL250R 1987 NT650 1988 TRX250 1986 CT90 1972 C70 1981 XR250R 1994    Report

06-04-2009, 11:25 AM fixer_27 Joined on 06-04-2009 Posts 2 Re: 83 cx650T sputtering/popping/bogging below 4000 Hi Guys, I'm new here, so if this post comes out weird, bear with me.  I'd like to suggest some reasons, one of which is a total shot in the dark. The reasonable thing to check is wiring and/or sensors with respect to vibration. I'm not sure how advanced this ECU is, but it may ignore trouble if the sensor goes back into range within a certain time, or it may have to fault many times in succession before a code is stored, and if the sensor becomes "good" it erases the count, thus not setting a code. I think the key is that the bike runs better cold. The ECU uses a different fuel map during cold operation, right? Like a substitute choke.  Either that enrichment is masking the problem when the bike gets warm, or the ECU is flat out ignoring the sensor input of the bad sensor when you fake cold operation.  This was my shot in the dark since I don't know the bike: does it have an oxygen sensor?  Most ECU's ignore the O2 sensor until the engine warms up, so the engine has no fuel management feedback.  The ECU may be using a different timing curve as well, or it may ignore the crank angle sensor, or "pad" it's input. Finally, maybe something silly like a vacuum leak leaning out the bike?  I figure that would show up as all-around bad performance, though. Scott.    Report

06-04-2009, 3:34 PM CXTURBOBOOST Joined on 05-02-2007 Lincoln, NE Posts 440 Re: 83 cx650T sputtering/popping/bogging below 4000 You are using modern day FI troubleshooting on a bike that was made in '83 and the R&D started in '78... No oxygen sensor on this baby... Pete    Report

06-08-2009, 6:22 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 Well I am finally moved and didn't have internet for the last couple of weeks. I tried taking the vacume/pressure tube off of the regulator and it mad a difference. It didn't default to a high limit but the fuel pressure probably did increase( still haven't confirmed pressure yet) at idle because normally the reg would be under a vacume, but when disconnected it would be at atmospheric. The bike now works better at lower RPM's and once you get into 4000 and above it now starts to pop and miss as it did before prior to me putting the POT in place of the coolant sensor. Also at idle if I pinch off the return line to the tank(with vacume hose still disconnected and POT turned to 2500 ohms) the engine starts to stall and the fuel pump shuts off. All these symptoms lead me to the conclution that the reg is the culpret. It has to be. I think for what ever reason the reg is out of range or is notchy. With manipulating the coolant sensor and the taking off the reg tube, the resulting symptoms say reg problem. If any of you could review my postings from the beginning to let me know if I am thinking straight or not would be appreciated.    Report

06-09-2009, 3:25 PM showkey Joined on 03-02-2007 Northern IL Posts 70 Re: 83 cx650T sputtering/popping/bogging below 4000 When you pinch the return fuel line to the tank the fuel pressure is going to increase to max output maybe 80 PSI....so the engine would being very very rich for idle......My guess thats why the engine stalls. I am a little suspect of the POT in replace of the coolant sensor.....I know resistance is resistance but???? I still think it lean, root cause of lean, reg, pump, sensor???? Also be very careful pinching without a gauge.........I did see on a car a line fail during a so called test with a 100 psi of pressure, the car and the tech were never the same. CX500T 1982 (3) Transalp 1989 GL1100 1983 XL250R 1987 NT650 1988 TRX250 1986 CT90 1972 C70 1981 XR250R 1994    Report

06-09-2009, 5:34 PM Don in Oz Joined on 03-10-2006 Melbourne, Australia Posts 546 Re: 83 cx650T sputtering/popping/bogging below 4000 Mate, Go buy yourself a fuel pressure gauge and DO the test - it will save you a lot of "ifs and buts" - and it will also give you the real facts on your fuel pressure regulator, instead of a lot of guess-work. I'm probably talking about a $30 gauge, while you're talking at least $100 for a regulator - which route is more cost-effective? Don. GL500I, CX500TC (2), CX500EC (2), 1982 CX500C. GL1000, 1976 CB550F, CT110 (2), XL125S (2), 1973 CB175K6. Kwaka Z250C1 (2). Suzuki GS450SX, DR250SJ, GS125ESD.    Report

06-13-2009, 2:28 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 I will. Thanks for everyones input. I will let you all know as soon as it's confirmed and how it works once I get a new FPR in place. Stephen    Report

06-17-2009, 7:33 AM wildmanwill Joined on 05-25-2008 Chester County, Pennsylvania Posts 4,034 Re: 83 cx650T sputtering/popping/bogging below 4000 Where are you located Stephen? Just wondering if someone might be near you... (Also you can add your location to your profile so that it shows up all the time) 1983 CX650 Turbo 1982 CX500 Custom Donating Member    Report

07-19-2009, 8:13 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 Well I just purchased a fuel reg off Dan Topping, Thanks Dan!! I will let everyone know what it works like after. If it isn't the reg then at least I have two regs and one more thing off my list of things that are NOT the problem. Here's hoping and a little prayin!! Stephen    Report

10-05-2009, 11:22 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 Well I put the reg in and nothing changed. I did however get an error code pointing to the engine speed sensors a couple of times. Has anyone got any advice on this?? At least i'm getting lots of spare parts. Stephen    Report

10-06-2009, 5:41 AM CXTURBOBOOST Joined on 05-02-2007 Lincoln, NE Posts 440 Re: 83 cx650T sputtering/popping/bogging below 4000 If you are getting a speed sensor code, it could very possibly be the problem....Especially if the water pump seal has gone out at some time and corroded the pick-up coils. I would clean and replace the coils to see what happens.... Insurance either way....    Report

10-06-2009, 8:33 AM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 are the pick ups still available or how do I clean them? I read somewhere that the coils are the same as whats used on 90's honda cars and other japanese cars of that era. They will fit in with a small modifications. Any info on this? My water pump seal does leak once in a while. I have checked the specs on the coils and they are what the shop manual says they should be. Could it be a problem only when the bike is running? Stephen    Report

10-06-2009, 3:39 PM CXTURBOBOOST Joined on 05-02-2007 Lincoln, NE Posts 440 Re: 83 cx650T sputtering/popping/bogging below 4000 NO NO.... Clean the housing and paint the pieces on the sensor (Base and "forks").... Replace the coils with new.... Pete    Report

10-06-2009, 6:35 PM HomerRod Joined on 07-21-2006 Posts 223 Re: 83 cx650T sputtering/popping/bogging below 4000 Stephen: One cardinal rule that I always followed as an Ford dealer tech (years ago!!) is this: "bad part does not mean a code, and a code does not mean bad part". Simply put, NEVER assume that a sensor is good, just because there is no ECU code or it passes the basic measurment test. One simple way to test the CX sensors is to start the bike, let her run at idle and warm up a few minutes. The shut her off, and disconnect the sensor plugs on the right side ONE AT A TIME ONLY. Restart, and you will see the "Fuel Warning" light illuminate as it supposed to. However, it the bike then runs normally, then you have found the culprit sensor, which probably measured within specs! (bad part doesn't mean code). The sam can be said about coils, wire and plugs. I never trusted the primary and secondary resistance measurements. Tap it,wiggle it, move it, shake the wires and watch the measurements move slightly. Take a know good coil and new wire and substitute it, again ONE AT A TIME. When the problem goes away, you've found the culprit. At the dealership we had the luxury of installing a new part from our shelf just to confirm our suspicions. I always kept a few spare coils, wires and sensors in my toolbox. We would charge the customer for 1.0 hour labor to diagnose, and I would usually find a rough idle or running problem in 10 or 15 minutes, unless there was a SERIOUS problem. Give it a try and let us know. And remember, YOU CAN DO THIS........    Report

10-06-2009, 8:37 PM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 I will let you know if it works. It will may be a while before I get to it as my wife is sick and we have two kids that have dance etc. etc. Time to myself with the bikes is very hard to get. I will get to it though! Stephen    Report

02-23-2010, 7:31 AM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 Well I figures it out. it was the engine speed sensors. one of the magnets under the mounting tangs was broken and with the mechanical seal broken the whole sensor assembly was very rusty and gross looking. i painted the plate and cleaned up the pickups so it looks like new. i epoxeyed it back together and it ran flawless. i am trying to get a replacement from Dan Topping but haven't heard back from him. what a difference!!!!!. thanks for everyones help. stephen    Report

02-25-2010, 7:25 AM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 The magnet was what I epoxeyed back together.    Report

02-25-2010, 1:17 PM Doward Joined on 05-11-2008 Alachua, FL Posts 814 Re: 83 cx650T sputtering/popping/bogging below 4000 Congratulations :) 1978 CX500 motor + 1980 CX500C frame    Report

05-11-2010, 10:57 AM IAWOESIWAK Joined on 05-11-2009 Vancouver Island Canada Posts 29 Re: 83 cx650T sputtering/popping/bogging below 4000 Well I thought I had it. After about 2 hrs. it went back to it's old self. I dug into it again and found that the tiny pin that locks the reluctor(triggers engine speed sensors) in place was too short and wore one side of the cut away groove in the reluctor like a slope. This translated into about 3-4 degrees of movement in the reluctor itself. As you can all appreciate this causes all kinds of timing issues. I couldn't fix the reluctor so i made a new pin, a bit longer so there is absolutely NO PLAY in the reluctor ant more. It has been weeks now and all is good. What a pleasure to ride. It wasn't the magnet after all!! Happy Motoring and thanks to all for advice and info. Stephen    Report

05-11-2010, 11:00 PM Don in Oz Joined on 03-10-2006 Melbourne, Australia Posts 546 Re: 83 cx650T sputtering/popping/bogging below 4000 Stephen, Thanks for that update - it's also something to look out for when putting the Ne sensors back in. Don. GL500I, CX500TC (2), CX500EC (2), 1982 CX500C. GL1000, 1976 CB550F, CT110 (2), XL125S (2), 1973 CB175K6. Kwaka Z250C1 (2). Suzuki GS450SX, DR250SJ, GS125ESD.    Report

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