Honda CX500 & GL500 Forum

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04-20-2009, 3:07 PM Harold Joined on 12-28-2006 Beside Washademoak Lake, N.B. Canada Posts 851 Vacuum Petcock Hose Diagram This is a crude diagram to show what hoses go where on a vacuum type petcock. "People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs." 1978 CX500 1980 CX500 Custom 1981 CX500 Custom 1982 GL500 Silverwing 1975 XL-100 http://www.myspace.com/downwiththebutterfly    Report

04-21-2009, 7:52 AM roundman72 Joined on 03-24-2009 Laporte Indiana Posts 393 Re: Vacuum Petcock Hose Diagram i just always remember the carb one goes towards the front of the bike 82 gl500I 82 xs650 70 cl450 (restoring) 74 cl450 (non runner) 00 Moto Guzzi Jackal (ended up selling)    Report

04-21-2009, 8:16 AM Zorce Joined on 03-11-2009 Marble Falls, Texas Posts 410 Re: Vacuum Petcock Hose Diagram My fuel line for my GL goes into the bottom carb on that diagram and the "airbox" hose goes down to the ground. The CX fuel line in in the middle like that? 1981 Honda Silverwing GL500    Report

04-21-2009, 8:41 AM Harold Joined on 12-28-2006 Beside Washademoak Lake, N.B. Canada Posts 851 Re: Vacuum Petcock Hose Diagram "My fuel line for my GL goes into the bottom carb on that diagram and the "airbox" hose goes down to the ground. The CX fuel line in in the middle like that?" The cx's with the vacuum petcock usually have the fuel inlet line in the middle of the carbs as above. The older ones have the inlet on the left carb body. The vent hose does go to the bottom of the bike not the airbox,, I actually started looking for a picture of the vacuum nipple on the carb, when I could not find one I made this drawing. Whenever someone asks where the vacuum hose is supposed to hook to the carbs, and they are told to hook it to the brass nipple on the right carb, I sometimes wonder if they find the vacuum nipple or the float bowl vent.  I wanted to have a good pic to point them to. Anyone have,, or know of a pic that shows the vacuum nipple clearly? "People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs." 1978 CX500 1980 CX500 Custom 1981 CX500 Custom 1982 GL500 Silverwing 1975 XL-100 http://www.myspace.com/downwiththebutterfly    Report

04-21-2009, 9:21 AM Lambykin Joined on 09-14-2008 Burlington, Ontario Posts 1,076 Re: Vacuum Petcock Hose Diagram I've got a set of GL carbs on the bench - want photos? 1982 GL500 Interstate 1981 CX500 Custom 1985 Pontiac Fiero (2 of 'em) 2005 Honda Accord EX-L V6 Coupe    Report

04-21-2009, 9:29 AM Harold Joined on 12-28-2006 Beside Washademoak Lake, N.B. Canada Posts 851 Re: Vacuum Petcock Hose Diagram  Thanks Lambykin, if you could get a good shot of the vacuum nipple, that would be good.  You can email it to me and I will post it, or if you want you can post it in this thread, whichever you prefer. "People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs." 1978 CX500 1980 CX500 Custom 1981 CX500 Custom 1982 GL500 Silverwing 1975 XL-100 http://www.myspace.com/downwiththebutterfly    Report

04-21-2009, 9:38 AM Lambykin Joined on 09-14-2008 Burlington, Ontario Posts 1,076 Re: Vacuum Petcock Hose Diagram I'll take several shots & post the photos. I have posted photos before in the forum, so it's not a problem. Now if I can only figure out how to post a link! ;-) 1982 GL500 Interstate 1981 CX500 Custom 1985 Pontiac Fiero (2 of 'em) 2005 Honda Accord EX-L V6 Coupe    Report

04-21-2009, 9:58 AM Harold Joined on 12-28-2006 Beside Washademoak Lake, N.B. Canada Posts 851 Re: Vacuum Petcock Hose Diagram  To add a link , copy the url you want to link to, highlight the words you want to represent the link by dragging the cursor over them with the left mouse button pressed, then IF your browser shows the buttons, click on the second from the right in the little toolbar directly above the textbox, a little window will open, paste in the url.  I usually type beyond the words I am going to use as a link before I highlight them,,otherwise anything more I type is added to the link. "People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs." 1978 CX500 1980 CX500 Custom 1981 CX500 Custom 1982 GL500 Silverwing 1975 XL-100 http://www.myspace.com/downwiththebutterfly    Report

04-21-2009, 10:13 AM bri-guy-ga Joined on 06-04-2008 Powder Springs, GA Posts 702 Re: Vacuum Petcock Hose Diagram I don't see this link on IE. What do I do? All I have are smiley face icons below the box. 1982 GL500i (currently being rebuilt from ground up) NO! Try not. Do or do not do. There is no try - Yoda    Report

04-21-2009, 10:40 AM Harold Joined on 12-28-2006 Beside Washademoak Lake, N.B. Canada Posts 851 Re: Vacuum Petcock Hose Diagram Test Link; see photobucket for hosting pics. Test Link Code; [$link=http://i663.photobucket.com/]see photobucket[$/link] for hosting pics. I tried this code in firefox and it works, you could try copying it and pasting it in the textarea(you will have to remove the dollar signs though, $ ), you may be able to tell if it works in the preview. It may not work in Internet Explorer, I can't even log in here with IE, if it does not work,,all I can suggest is that you download Firefox "People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs." 1978 CX500 1980 CX500 Custom 1981 CX500 Custom 1982 GL500 Silverwing 1975 XL-100 http://www.myspace.com/downwiththebutterfly    Report

04-21-2009, 11:23 AM redryder Joined on 01-16-2007 Orange, CA Posts 213 Re: Vacuum Petcock Hose Diagram So I have the vacuum petcock on my 81c.  Before I installed my tank, I opened the petcock to the "on" position and fuel flowed out...  hmmm..   Obviously no vacuum was needed to release the diaphragm.  I hooked up the tank and connected the vac hoses correctly (as pictured here).  I turned the petcock on, allow the float bowls to fill and the bike ran good for ~3 minutes then it died.  Let the bike site for 5 minutes, started it, and again it ran for ~3minutes then died.  I opened up the petcock and found the spring on the wrong side of the diaphragm - so the vacuum was actually closing the diaphragm and cutting fuel flow off *edit* while the engine was running.  I corrected the spring placement, hooked up all the plumbing and all is working as Mr Honda intended.. Just an FYI in case anyone wants to convert their vacuum petcock to a conventional one..  Of course you'll have to diconnect the vacuum line from the petcock and plug it (a golf tee works good). Paul 81 CX500C 79 CM400T (seized) 81 CM400E (next project) 99 CR250 FAQ thread    Report

04-21-2009, 1:17 PM Lambykin Joined on 09-14-2008 Burlington, Ontario Posts 1,076 Re: Vacuum Petcock Hose Diagram As requested, here is the nipple on the right carb where the petcock vacuum should connect. These carbs are from my GL500 Silverwing, but looking at my '81 CX500 Custom, the carbs look to be identical (my CX500 also uses the vacuum-operated petcock). Picture of right-side carb, with the throttle plates facing the camera. This is the side of the carbs that face the engine. Notice the nipple over the top-left throttle intake, just below the phillips screw that secures the top cap. Here's an overhead view - this is much like what you would see from the perspective as if the carbs were installed in the bike. The right-side carb is at the top, and the left-side carb (which isn't pictured) would be at the bottom. You can see the round throttle intake, the nipple, and again, the screw to the top cap of the carb. For quick reference, the nipple is to the left of the phillips screw pictured. Total front view of both carbs - note that the nipple is slightly lower than the top of the carb body: Complete top view of both carbs - throttle side of carbs are pointing down. As you can see, the nipple is just below the screw on the carb on your left (while it's on your left, this is the right-side carb): Hopefully it will be very obvious where the petcock vacuum connects. Sorry my carbs aren't super clean & super-shiny. They are clean on the inside, and work very well, and that's all that matters. :-) 1982 GL500 Interstate 1981 CX500 Custom 1985 Pontiac Fiero (2 of 'em) 2005 Honda Accord EX-L V6 Coupe    Report

04-21-2009, 4:57 PM Harold Joined on 12-28-2006 Beside Washademoak Lake, N.B. Canada Posts 851 Re: Vacuum Petcock Hose Diagram Thanks Lamykin, those pics show it clearly. "People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs." 1978 CX500 1980 CX500 Custom 1981 CX500 Custom 1982 GL500 Silverwing 1975 XL-100 http://www.myspace.com/downwiththebutterfly    Report

04-21-2009, 6:27 PM Lambykin Joined on 09-14-2008 Burlington, Ontario Posts 1,076 Re: Vacuum Petcock Hose Diagram No problem... 1982 GL500 Interstate 1981 CX500 Custom 1985 Pontiac Fiero (2 of 'em) 2005 Honda Accord EX-L V6 Coupe    Report

04-28-2009, 9:29 PM Dash Joined on 08-25-2008 San Francisco, California Posts 628 Re: Vacuum Petcock Hose Diagram Neither carb on my '82 CX500 has a vacuum nipple anyplace on them.  The vacuum source to the petcock comes from the test port screw in the carburetor inlet tract.  The previous owner put a 5mm set screw the he had drilled to make hollow into the port and pushed a rubber hose onto it.  This can't be the factory set up but here else would the vacuum source to the petcock come from? What order are the parts to the vacuum petcock supposed to be assembled?  Mine has a big diaphram with a big tear in it, a hard plastic disc about the size of a U.S. quarter that has rings on one side, a spring, a small aluminum disc smaller than a dime, a weird little rubber thingy that is die-cut. '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

04-29-2009, 6:11 PM Harold Joined on 12-28-2006 Beside Washademoak Lake, N.B. Canada Posts 851 Re: Vacuum Petcock Hose Diagram Here is a link to a parts fiche showing an 81 Custom vacuum petcock, you can also find your 82 model if you look through the site. "This can't be the factory set up but here else would the vacuum source to the petcock come from?" Your bike may have had the carbs replaced with carbs from an older model cx (78-80), which never had the vacuum petcock. "People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs." 1978 CX500 1980 CX500 Custom 1981 CX500 Custom 1982 GL500 Silverwing 1975 XL-100 http://www.myspace.com/downwiththebutterfly    Report

04-30-2009, 1:54 AM Dash Joined on 08-25-2008 San Francisco, California Posts 628 Re: Vacuum Petcock Hose Diagram Well that must be it then -- previous owner must have replaced the carbs on my '82 CX500. These carbs do have an accelerator pump. Guess I'll just live with having a vacuum hose running to the test port. On a good note, I bought a petcock rebuild kit for $16 from KC Engineering here in San Francisco. Once I looked at the new parts, assembling it all kind of just fell into place and it only took me 15 minutes. Now I'm petcocking with the best of 'em. On a frustrating note, I'm getting to be an expert at removing and installing CX500 carburetors. Today I had them completely in and completely out three times. Right now they're out again. I'm going to time myself tomorrow and see how fast I can install them. '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

10-15-2009, 7:58 AM redneckconvert Joined on 10-15-2009 Posts 2 Re: Vacuum Petcock Hose Diagram Hey, this is exactly what I needed. The guy I want to buy an 81' CX500C off of had no clue what that nipple was, he thought it was overflow or something. So naturally he could start the bike up, but he could never get it in gear and get it to drive. Awesome info.    Report

10-19-2009, 12:21 PM wildmanwill Joined on 05-25-2008 Chester County, Pennsylvania Posts 4,034 Re: Vacuum Petcock Hose Diagram Hopefully you can get the bike for a good price... 1983 CX650 Turbo 1982 CX500 Custom Donating Member    Report

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