CX500 GL500 650 Global

Yeah go for good old GeorgeFix. I use them quite a bit. or
Sirius Consolidated Inc
both seem like great places for me.

I pulled the plugs and they were all black and carbony. It cleaned right up with a brass brush and some brake cleaner. That tells me its running to rich. correct? I also drained the tank into a container with 2 layers of paper towel over the opening. I got a bit of brown residue so looks like it wasn't rinsed enough. Weird part is I couldn't get the petcock to flow. I hooked up to both fitting and tried vacuum and pressure and nothing. On reserve I got a little out, but nothing on main. I took the petcock completely apart and didn't see anything obviously dirty, but cleaned it all up with brake cleaner just the same. I pulled the carbs and without seperating them took out everything I could and cleaned every opening with carb and brake cleaner. No real filth, but its clean now. I also didn't notice much in the way of gas in the bowls and don't think I spilled much out. The petcock drain was full though. Will put it back together after rinsing the tank for quite a while. Will it be ok to flush with water then coat it with coke? I don't want anymore rust in this thing. I pulled the idle screws out and reinstalled them all the way and then backed them out 1 1/2 turns is that right? Without a rebuild kit and some smaller screwdrivers for inside the jets thats all I could get clean tonight. If this gets it going I will go for a complete tear down after I get a spare set of carbs to play with while I work out the other bugs. Is there a way to rough sync them on the bench?

Yes, it is running rich, but why? The needles and floats seem to be my first thought.

Ok, try this on the tank. Drain it out and go get a gallon of muratic acid at a home supply store or a pool supply store. Pull the petcock and plug the tank with a rubber plug. Fill the tank with 50/50 mix of the acid and water, and let it sit over night, or at least 24 hours. Do this out side and try not to breath the fumes. After the soaking, pour it out into a safe plastic container. Rinse it out vigorously with a water hose. You can put the gravel in there while you do it too. You can use this solution to dissolve rust on other parts later. After I did this, I poured WD40 in the tank and got it coated inside so it would not rust. Rinsing with gas would work too. I have not used the coke, so I can't comment on that. Shep could tell you better.

I do not have a vacuum petcock on my bikes, so I can not help with a diagnosis on it, but it sounds like this is a major problem that is hitting you in the face. Not sure what you mean by the petcock drain.

To get the carbs closely synced on the bench, hold a light on the intake side of the carbs, (choke side) and let the light shine through so you can see it under the throttle plates. Adjust the balance screw so that there is as close of a even gap under each side as possible. This has always resulted in a very close sync, and starts well for an off the bench setup.

1 1/2 turns is Ok. you can go one way or another from there. You will probably have to turn it out to 2 or more if it keeps running rich.

What do you mean by small screw drivers for the jets?

I will get the acid and pour it and a gallon of water into the tank and let it sit and do its thing. Then do the WD40 thing. Will this acid/water mix be safe for chrome or aluminum parts, later?

The carbon wasn't baked on or anything, just sitting there. It came right off, so I don't think it has been running rich for very long and I never noticed black smoke from the exhaust like you would normally expect.

When I removed the jets from inside the bowls there was another brass looking part inside the carb under the jet. There are two jets, one sitting on a removable fitting that goes down to the piston and the other. Well under that other one I saw what looked like a removable brass part. From my parts fiche I think its #23 (main nozzle). I didn't have a small enough screw driver to get that one out. I will have to see about a thin screwdriver that when I get the acid.

Petcock drain is that little cup under the valve where the screen sits. I also pulled the valve covers and everything is nice clean and oily.

Bad new, George doesn't stock a carb kit for the GL500, just CX's.

The 112 jet goes in the Brass holder.The 78 goes into the carb.
What type of float needle valve do you have?Does it have a small metal spring on it that slots onto the float?
If so then george's kits are the same as that.There are only really two types of carbs used on these bikes with very minor differences e.g one uses a white/Cream/Brown float that has a float needle that doesn't use a small spring and the other type are black floats with the spring float needle.





Also back to basics.All internal combustion engines require Ignition/Compression and fuel.All these have to be nominal to work correctly.

Thanks Shep.
I have the orange/brown float with a float needle like the top picture. It seems the carb kit is mostly o rings, as I understand its best to reuse the jets and valves. The only specific part is the bowl gaskets.

According to Randakk the later CX's and GL500s are the same, just the carbs are spaced slightly further apart. If I get a '82 CX500 kits all the o rings should fit. He does make a nice looking kit though.

Yes to be honest unless your O-rings/jets are really damaged the kits are not needed.You can use a thin smear of RTV on the carb bowl seals but you have to wipe off ALL the excess as you don't want any getting into the bowls.One of my CX is done this way with no problems.What I did was put a thin smear under the seal in the bowl groove .Then wiped the excess.This raised the seal that had become flattened with age.
The only really nasty little O-rings are the ones that go on the idle screw.If they are OK I'd re-use what you have for now

I am going to go with the assumption that you have done the acid/water thing before and that it won't hurt my tank (ie. burn holes in it). I guess if I left it there for a week it might do some damage, but a day or so should be fine. Will get some tonight and see what sort of muck I can get out of there.

Well did the acid/water thing and left it sitting overnight outside. Came out this morning and found two wet trails on the driveway. Looks like the acid ate a couple of pinhole sized holes on the underside where the outside and bottom parts of the tank come together toward the seat end of the tank. Looks like now I have to get a tank liner. I have had good success with POR before so may give that a shot, I might also have some left from my last car project. Any other suggestions? Other than that the sucker looks real clean and shiny. Will let you know how bad the leak is tonight when I have time to get into it more.

Years ago on my Norton's tank I had a seam leak at the weld where the tank had,"Chattered" against the frame because the rubber protector had perished.I mixed up some Polyester resin(Stuff you use with fibreglass matting for car/dent repairs) and poured that in and left the tank at the correct position/angle so the resin would collect at the point where the leak was and then left it in the warm in the house over night to cure.

A pal of mine years ago also had a small rust hole under the bottom of his BSA tank.He cleaned around the rust hole/wire brush etc then stuck a piece of Exhaust alloy repair tape over it and then painted over it with some Poly Resin.Then stuck a bigger piece of Innertube rubber over it.

Both worked a treat