Honda CX500 & GL500 Forum

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03-08-2010, 6:51 AM PT-13Pilot Joined on 08-25-2009 Belle Missouri Posts 54 About to throw in the towel 82 GL500 Been a while since I've posted. The 82 GL500 I bought last summer to fix up is finally getting some attention again. Unfortunately, I'm about to throw in the towel, having running issues and can't for the life of me get it fixed. It's had this problem since I got it, and figured my usualy anal retentive tweaking would fix it, it has on many other old Hondas, but not this one. It runs rich, really rich, to the point it is not rideable. Here's a list of things I can think of that would affect it. That being said, it will start right up on both cylinders and idle fine all day if you let it. Any ideas appreciated, I'm about to the point of parting it out, out of spite. Carbs cleaned, new seals, needles, accelerator pump, cutoffs, etc. Float levels at as close to 15.5 as possible. Jets and all correctly installed. I've cleaned a ton of carbs on the 4 CB900C's I've owned, never had a problem getting them to run like a sewing machine. Carbs synced. Pilot screws played with from all the way in to 4 turns out, just trying. Slides clean and free. Choke's work fine and not stuck on in any way. New air filter, and removing it makes no change. Electrical: Every wire, connection, ground, etc, cleaned and corrosion proofed. I do this just because. New OEM spark plug caps and new wires. 3 new sets of spark plugs. 2 sets of coils, 2 sets of spark units. Has strong spark. New battery. Charging system strong, pulls 14.5 volts at anything above 1500 RPM's. Checked timing idling, spot on. Haven't got a good reading above that, tired of oil in the face and making some sort of window hasn't worked. Fuel shutoff rebuilt and obviously works fine. Fuel filter inline to carb. Fresh gas, tank clean. Engine: Bike has 6900 miles. Compressions both 170 PSI, valves adjusted. No leaks. No oil in coolant or coolant in oil. Exhaust has no restrictions. What it does and things I've tried: It will idle and rev on the center stand. It falls on it's face between 3000-6500 RPM's but you can throttle past it. It will rev to 8500 and will stay there if you let it. So mechanical advancer isn't stuck. I've had bikes that had one stuck and they won't run above 3000 period. If you get on the bike and try to take off, it immediately falls on it's face off idle and floods. Dry black sooty plugs. Start it up again, it will eventually idle fine again. Shuting off fuel helps. If you shut off fuel till it runs well again, nail it, and take off. She takes off like a rocket untill the bowls run out. 1st gear to 9K and accelerates hard just for a few seconds. Still thinking something in carbs. Verified they are the right carbs bodies. All stock jetting with factory jets & internals other than soft parts replaced. No signs of drilling the jets or anything shade tree. I'm at my wits end. I've spent countless hours and a lot of money on it. I have a beautifull 81 CB900C and I've lost all interest in this GL. I want it running or want it gone. Any ideas appreciated. Otherwise opening the carb drains and lighting a match is starting to seem like a good idea. 1982 GL500I 1981 CB900C    Report

03-08-2010, 8:03 AM Blue fox Joined on 04-18-2008 COLUMBIA, MISSOURI Posts 1,533 Re: About to throw in the towel 82 GL500 Gosh, it sounds like you have tried most everything, and some things twice.  It is still pointing to a carb issue I think.  If it is running rich and flooding, with black sooty plugs, it can't be electrical.  I have a possible solution, I picked up a set of carbs for a GL500 off the bay last year.  They were listed as for parts only, but I took them apart and cleaned them the best I could at the time.  I didn't have a ultrasonic then, so just the standard stuff.  Anyhow, they may or may not be good, but if you wanted to try them, I would be willing to help out another guy in Misery.  Just let me know and we can figure out details. I wonder if maybe a PO has put the wrong float needles in and that is upsetting the fuel delivery?  I had a CX last year that wouldn't run right at speed either.  I took a 2 foot long clear tube and attached them to the drain ports of the float bowl.  Then looped them up and tied them above the carbs.  Opened the drain screws a turn or two.   When it started to run screwy, I could check the fuel level immediately by just comparing the level of the fuel in the lines to the carb float bowl.  The level should be slightly below the seam of the bowl/carb body.  I can't remember exactly what was finally wrong with my carbs, but this helped isolate the problem. Blue Fox 1983 GL650I, 79-CX500C, 1980 CX500C, 82-GL500I, 82-GL1100, 76-CB550, 81-CB750C, 73-CB350F, 71-CT90,    Report

03-08-2010, 8:18 AM PT-13Pilot Joined on 08-25-2009 Belle Missouri Posts 54 Re: About to throw in the towel 82 GL500 Blue, Thanks for the offer, I'd be glad to take you up on your offer. Let me know what you need for them. I checked the fuel level with the tubing like you talk about, and it's right around the seam. At least some oem and aftermarket wise, the GL and my CB900 use a lot of the same parts. I have alot of spares for it. I've even tried swapping floats and new float needles from my stash. No go. End result is the same. I even tried a spare set of floats, trying to lower the fuel level artificially by adjusting them. Just ran crappier, and still rich. I don't have an ultrasonic either. But the inside of these are really nice. For the tiny passages I use a blow gun with a small inflation needle (like for a basketball), with the tip ground to a point. .020 safety wire for all the small holes, and compressed air and blow gun for the rest. Also, a soak of brass parts in Hoppes #9 makes them look like new. They are obviously clean enough to flow too much gas! If you want, email me direct crjella at charter dot net. Thanks a bunch for the offer. CJ 1982 GL500I 1981 CB900C    Report

03-08-2010, 9:50 AM Blue fox Joined on 04-18-2008 COLUMBIA, MISSOURI Posts 1,533 Re: About to throw in the towel 82 GL500 I may disassemble them again before I ship them out. And run them thru the ultrasonic for awhile just to make sure they are as clean as I can get them.  That may take a day or two.  As far as payment, let's just see if they help first.  I don't even remember how much I payed for these, but it wasn't much, under $20 I think.  I'll e-mail you for a shipping address and other details.  Glad to help.  Blue Fox 1983 GL650I, 79-CX500C, 1980 CX500C, 82-GL500I, 82-GL1100, 76-CB550, 81-CB750C, 73-CB350F, 71-CT90,    Report

03-08-2010, 6:23 PM timk Joined on 02-26-2008 Hubbard Oregon Posts 519 Re: About to throw in the towel 82 GL500 Note or disclaimer: I have not disassembled these carbs before,.. I thought there were 2 sets of jets (idle set and run set?) and 'If' I remember, someone had put them in the incorrect locations during a rebuild... Couple GL's and CX650 ... everythings in work....    Report

03-08-2010, 7:29 PM Spacetiger Joined on 05-16-2009 Chantilly, VA Posts 1,353 Re: About to throw in the towel 82 GL500 I thought there was someone on the site last year that had a leaking fuel problem that was coming from the petcock or accelerator pump on one of the carbs(?). As soon as the bad side was traced, the poster was able to back into which carb and where the excessive fuel leak was coming from. Does anyone remember who this was? 90 PC 800 (commuting steed) 82 GL500I (50+mpg, great bike) 66 BMW R 50/2 (No brakes/HP) 80 CX500C (Loved this bike) 74 CB360 (Fun; but too small) 79 CX500D (40,000+ mi in 3 years) 76 CB550 (step up from 200cc) 74 KZ200 (1st bike!)    Report

03-08-2010, 7:36 PM BillRod Joined on 11-09-2009 Richton Park, IL 33 miles SW of Chicago Posts 350 Re: About to throw in the towel 82 GL500 I know very little about these carburetors. My experience has been with Yamaha's and I know that the needle in the slide has a taper where it goes into the main jet. The top of the needle has 5 groves and a single "C" clip that can me moved from grove to grove. If you move the "C" clip up on the needle it leans the mixture by lowering the needle. If moved down on the needle it richens the mixture by raising the needle. The slides also have a cut away on the side that is away from the engine. Years ago Yamaha had a 2-cylinder engine that you could actually swap the slides from one carburetor to the other. The problem was to do this you would have to rotate the slide 180 degrees and the cut away would then be toward the engine. We had a customer come in with his bike saying it needed a tune up. Every time we would start it, it would run for a few seconds and flood out. When we took the carburetors apart we discovered the customer had done exactly what I have described above. When reassembled correctly the bike ran fine. It is funny how the owners never want to tell you what they did before they gave up and brought it to a dealer. Like I said, I know very little about these carburetors but if the needle can be raised or lowered it will effect the mixture. If the slide is in backwards it richens the mixture dramatically almost like a choke. In the Yamaha carburetors slides can be purchased that have a different cut away for tuning purposes but most tuning that I have ever seen was with the “C” clip on the needle. I hope this helps as this problem seems bizarre. BillRod 71 years old (April 1939) Richton Park, Illinois Just bought 1982 GL500 Naked 13,000 miles Never worry about theory as long as the machinery does what it is supposed to do.    Report

03-08-2010, 8:02 PM Blue fox Joined on 04-18-2008 COLUMBIA, MISSOURI Posts 1,533 Re: About to throw in the towel 82 GL500 I don't think the CX or GL carbs have the notched needles in the secondary.  If I remember correctly, you can't change the mixture without putting a small washer under the needle seat.  I think this may also restrict the movement of the needle too.  It will not have the wobble needed to move up and down in the jet properly.  And the "black banana" only allows the slide to go in one way.  The slot on the slide accepts the tab on the banana.  Blue Fox 1983 GL650I, 79-CX500C, 1980 CX500C, 82-GL500I, 82-GL1100, 76-CB550, 81-CB750C, 73-CB350F, 71-CT90,    Report

03-08-2010, 9:12 PM kenglong Joined on 06-04-2006 Albuquerque, NM Posts 266 Re: About to throw in the towel 82 GL500 The carbs from my '83 GL650 are currently off the engine and sitting in a box until I get around to putting everything back together. If it would help, I would be willing to disassemble and post pictures of any part you need to see. My carbs are absolutely stock. Ken in Albuquerque '83 GL650 Silverwing    Report

03-09-2010, 7:35 AM Dash Joined on 08-25-2008 San Francisco, California Posts 628 Re: About to throw in the towel 82 GL500 Sounds to me like your carb needle valves aren't seating properly.  Turning off the fuel petcock makes your bike temporarily run better because gasoline isn't flooding into the carbs. '67 Honda Dream '70 Moto Guzzi Ambassador '75 Suzuki GT250 '76 Goldwing '81 GL500 Silverwing '82 GL500 Silverwing <--just bought it 16 Mar 2010 '90 Yamaha XT350 '91 Kawasaki KDX200    Report

03-09-2010, 9:19 PM BillRod Joined on 11-09-2009 Richton Park, IL 33 miles SW of Chicago Posts 350 Re: About to throw in the towel 82 GL500 I have to agree that the only thing left are the carb needle valves. I read somewhere that they very seldon wear out and that non Honda replacement parts are shorter than the originals and can cause problems. It would be interesting to see the original and replacement side to side. BillRod 71 years old (April 1939) Richton Park, Illinois Just bought 1982 GL500 Naked 13,000 miles Never worry about theory as long as the machinery does what it is supposed to do.    Report

03-10-2010, 7:07 AM PT-13Pilot Joined on 08-25-2009 Belle Missouri Posts 54 Re: About to throw in the towel 82 GL500 I agree on the needles. Problem is I have several OEM needles. They are old and hard, but for comparison purposes I couldn't see a difference. And if they weren't sealing, they'd overflow. And I haven't had any of that. I polished the seats. I also polish the float pivot pins so there isn't any friction. I even took an old set of floats and adjusted them to artificially lower the fuel level in the bowls, just a last ditch effort. It just ran worse, and didn't make the difference I'd hoped for. Blue is sending me some carbs to play with. I'll see what happens. Hopefully good things. It's nearly done otherwise. 1982 GL500I 1981 CB900C    Report

03-17-2010, 11:22 AM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 1,899 Re: About to throw in the towel 82 GL500  PT-13Pilot wrote: I checked the fuel level with the tubing like you talk about, and it's right around the seam. Am I the only one that thinks the fuel level should be about a cm lower than this? Your symptoms really sound like at least one bowl is overfilling. Try checking where the float valves open. Turn off the fuel, remove one float bowl, lay a big rag across the back of the engine below the carbs, hold the float up and turn the fuel back on. No fuel should flow (duh). As you lower the float, the fuel should start to flow when the upper surface of the float is just about parallel to the carb body. If it flows while the float is higher than that you have found the problem. Mr. Honda ('83 GL1000/Dnepr) summer The Famous Eccles ('84 GX650EI/Velorex700) winter WHY I HAVEN"T BEEN AROUND MUCH LATELY    Report

03-23-2010, 9:00 PM OLD MAN CX500 Joined on 02-02-2010 Posts 164 Re: About to throw in the towel 82 GL500 I checked the after market needles are the same lenght as the oem parts, I also have floats that do a dive when the engine is running when shut off they hold the gas good hit the start botton and down they go this may be your problem    Report

03-23-2010, 9:45 PM Panther Joined on 05-09-2006 Las Vegas, NV Posts 1,264 Re: About to throw in the towel 82 GL500 I think I remember a post a few years ago about the three jets in these carbs They had mixed the Slow jet with one of the others. Gave some very similar problems to yours. They are what, a #112, a #45 and a #78. Mix in the 78 or 112 into your 45 spot and you can imagine how bad it might run. But I would bet you have the 112 and 78 backwards. I think the 78 is the main and the 112 is something for the midrange. aka off idle to 3/4 throttle area. I would also check your floats to make sure they are actually sealing right. The vibrations from a running motor can cause them to let the fuel get a bit higher. My first though was a "heavy" float, but if you have swapped them out, I don't think that is the problem. Where is that picture that shows the carb passages and stuff? Peace & Light >^..^< .......... '83 GL650swi "My Little Grey Lady" '82 GL500swi parts bike '78 DT175 '86 LS650 Milady's bike    Report

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