plenum or petcock

Discuss everything about Honda GoldWing. Feel free to ask any question related to GoldWing.

Moderators: CYBORG, Oldewing, robin1731, Forum Moderators

Post Reply
User avatar
robin1731
Membership Admin
Membership Admin
Posts: 21724
Joined: Mon May 29, 2006 8:31 am
Location: Decatur, Indiana

Re: plenum or petcock

#16

Post by robin1731 »

ifm61 wrote: Tue Jun 28, 2022 10:29 pm yup, i read the Randakks post on 'common' mistakes made when attempting this, and stopping reading after 30... hence the seasoned pro comment
I know a guy. ;) lolol
1976 Goldwing Super Sport
1985 Honda Elite
1976 KZ900 Dragbike
1992 ZX7 Dragbike (KZ900 style motor w/NOS)
and a rotation of various purchases
Randakk approved Carb Rebuilder
User avatar
gltriker
Honored Life Member
Honored Life Member
Posts: 5053
Joined: Fri Sep 24, 2010 9:11 pm
Location: central NY State

Re: plenum or petcock

#17

Post by gltriker »

robin1731 wrote: Wed Jun 29, 2022 1:27 pm
ifm61 wrote: Tue Jun 28, 2022 10:29 pm yup, i read the Randakks post on 'common' mistakes made when attempting this, and stopping reading after 30... hence the seasoned pro comment
I know a guy. ;) lolol
Definitely, a "Seasoned Pro" guy tumb2
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
ifm61
Billet Alum. Member
Billet Alum. Member
Posts: 281
Joined: Thu Oct 23, 2014 8:44 pm
Location: canada

Re: plenum or petcock

#18

Post by ifm61 »

for sure Cliff, i promise. incidentally I appreciate the edit on an earlier post. 'glaringly obvious' is the name of the lead character in the movie of my life. played by Brad Pitt obviously...
User avatar
gltriker
Honored Life Member
Honored Life Member
Posts: 5053
Joined: Fri Sep 24, 2010 9:11 pm
Location: central NY State

Re: plenum or petcock

#19

Post by gltriker »

tumb2 yeah, although I do that occasionally when addressing a posed to the group question, after I recognize its been seen, removing it soon afterwards is good form.
I haven't been riding my trike for 2 years. If I can help others with their ride, it's good for my head. ;)

Brad Pitt, eh?..
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: https://nakedgoldwingsclub.com/forum/page/Welcome

previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
User avatar
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Re: plenum or petcock

#20

Post by ericheath »

Before throwing in the towel, you need to determine what is leaking. Your description certainly sounds like a leaking float needle, but could be a carb-to-plenum gasket, a fat oring which seals the fuel port from carb to plenum, or it could be the plenum seal.

You’ve observed step one of diagnosis, turning the fuel off causes it to run better for a short time. To determine what is leaking, you need to go a step or three further. Each case will eventually require removal of the rack eventually, but not necessarily a full strip down rebuild, even though it is highly recommended so you aren’t doing it again next year.

1. Suspend a liter or more of fuel six feet above the bike, by-pass the fuel pump by hooking the inlet going from your source to the carb rack direct. A longer hose is helpful. (I’ve done this just bypassing the the fuel pump and having a full tank of fuel, but it might not generate enough working pressure to simulate the pumps pressure.)

2. Remove the air cleaner cover and air box and filter. Dry off the floor of the plenum. Cut and place a piece of paper towel or absorbent paper in the floor of the plenum so it sits flat on the floor. With the bike level, turn the fuel on with a flashlight handy and observe whether fuel shows up along the centerline of the plenum floor or towards one of the carburetors. If it’s along the centerline, it’s your plenum gasket.

You’re probably done, but the other checks could rule out other issues.

3. Undo the eight bolts holding the intake elbows so the rack can slide each way. Remove the elbows. They require heating the rubber and an up and down motion to get them started. (Worst part of the job)

4. Remove the two screws holding each carb cap, then remove, mark/label and keep together each cap and slide.

5. You should now be able to slide the rack towards each side enough to gain clear view into the carb throats. If not, you might need to undo the choke cable and throttle cables at the rack. No need to remove them from the bellcrank yet. (But likely)

6. Make sure each throat is clean and dry and the rack is level. Have your flashlight handy, and turn the fuel on, looking into each throat for the first sign of fuel. You’re trying to determine if fuel comes up through the brass jet(s) first or if it comes from the area between the jets and plenum. I’ve had all three.

If it comes from the jet first, it’s your float needles. If it comes from the plenum side, it’s your carb-to-plenum seal.

The plenum seal and carb-to-plenum seals can be replace without a full tear down, but the float needles will require bowl removal, float removal which is tedious if the pin the float rests on is stuck, and getting the seat for the needle out is often no picnic either.
DCEB43AE-70B6-4C0A-8B5A-7C8E0A1E5021.jpeg
DCEB43AE-70B6-4C0A-8B5A-7C8E0A1E5021.jpeg (371.59 KiB) Viewed 303 times
C26209C0-65C8-4AC5-8AF4-A706EF172B11.jpeg
C26209C0-65C8-4AC5-8AF4-A706EF172B11.jpeg (374.99 KiB) Viewed 303 times
The linkages will allow the racks to fold like an accordion to replace the plenum seal or the carb inlet seal at the plenum.

There is an offset connector for each choke mechanism. It will likely fall out if doing the carb-to-plenum seals. Get them back in place before reassembly. It only takes six tries. A piece of tape might help if you can get your finners in there.

Rebuilding the carbs is very doable, but requires care. My first set resulted in a destroyed rack of carbs. The PO gave them a head start with stripped float bowl screws. I broke a tower for the floats, and committed many faux pas along the way. There are good vids available now.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
ifm61
Billet Alum. Member
Billet Alum. Member
Posts: 281
Joined: Thu Oct 23, 2014 8:44 pm
Location: canada

Re: plenum or petcock

#21

Post by ifm61 »

appreciate you chippin' in mate but first mention of the carbs having to be removed and that towel got chucked in... don't have the room, light, tools, experience or inclination. banjaxing the carbs with the best of intentions will just leave me with a duff bike stuck in a doll house.
i'm willing to try a Seafoam flush (or the Berryman B12 if i can get my hands on any) running out the fuel in the carbs repeatedly in the hope whatever is stuck will dislodge.
should that fail, i'll pull the plugs and crank the engine and whichever hole gas sprays out of should indicate which carb has a stuck float. i can then drain that bowl and see if it makes a difference.
i'll also remove the air box and hope to see a dry plenum floor.

if none of that works, its the phone book and me passing on my findings to someone who knows what they're doing. sure, $$$, but sometimes you just gotta bite that bullet
User avatar
pidjones
SUPER BIKER!!!!
SUPER BIKER!!!!
Posts: 3237
Joined: Wed May 22, 2013 4:06 pm
Location: East TN

Re: plenum or petcock

#22

Post by pidjones »

Just beware of "mechanics" that don't really know these carbs. Too many have taken their GoldWings to folks that have never worked on one, only to be stuck with a bill and barely-running bike.
"Love 'em all.... let God sort 'em out!"
Ex 2006 GL1800 - the Black Pearl SOLD! to make room for:
2021 Can-Am Spyder RT Limited Dark Chalk Metallic
1975 Red GL1000 project - ex Pistol Pete project
1972 Triumph T150V Trident rescue - finished and FOR SALE!
1976 Yamaha RD400c
1978 GL1000 with '75 engine - the Hunley
Ex 1978 GL1000
Ex 1979 GL1000
Ex '79 CB750F rat bike
Ex '86 SEi
Ex '77 GL1000
Ex '76 RD400
Ex '72 Penton 125 set up for flat track
Ex '73 RD250
Ex '68 TR6C - chopped
redglbx
Gold Member
Gold Member
Posts: 1116
Joined: Tue Jun 02, 2020 8:39 am
Location: NW Indiana,

Re: plenum or petcock

#23

Post by redglbx »

As PID says ! I have redone a number of carbs that “experts” have supposedly done that had wood screws & sheet metal screws holding things together ! I have a 80 1100 currently that a friend took to an “expert” and payed a lot of money to and had it sit in their shop for months only to get it back in barely running condition with wood screws holding the bowls on. Currently it won’t run at all but it will pop.. just piss’s me off to see this kind of stuff.

The “expert” is a self proclaimed GW all knowing guy, he just effed these carbs up ! I hope they are salvageable going to need a bunch of helicoils at the least.
Red 1976 oe owner
1976 LTD restored
1980 CBX , in the que, to fix the ignorant heavy handed owner
1981 CBX
1977 CB750 K7
2014 FJR OE owner, sold
1980 GL1100
1984 GL1200 naked
1969 CL350, in the que
User avatar
pidjones
SUPER BIKER!!!!
SUPER BIKER!!!!
Posts: 3237
Joined: Wed May 22, 2013 4:06 pm
Location: East TN

Re: plenum or petcock

#24

Post by pidjones »

redglbx wrote: Fri Jul 01, 2022 8:06 am The “expert” is a self proclaimed GW all knowing guy, he just effed these carbs up ! I hope they are salvageable going to need a bunch of helicoils at the least.
Helicoils are cheap on Amazon. Well, not true Helicoils, but if you have a true Helicoil kit they go in with the same tools.
"Love 'em all.... let God sort 'em out!"
Ex 2006 GL1800 - the Black Pearl SOLD! to make room for:
2021 Can-Am Spyder RT Limited Dark Chalk Metallic
1975 Red GL1000 project - ex Pistol Pete project
1972 Triumph T150V Trident rescue - finished and FOR SALE!
1976 Yamaha RD400c
1978 GL1000 with '75 engine - the Hunley
Ex 1978 GL1000
Ex 1979 GL1000
Ex '79 CB750F rat bike
Ex '86 SEi
Ex '77 GL1000
Ex '76 RD400
Ex '72 Penton 125 set up for flat track
Ex '73 RD250
Ex '68 TR6C - chopped
ifm61
Billet Alum. Member
Billet Alum. Member
Posts: 281
Joined: Thu Oct 23, 2014 8:44 pm
Location: canada

Re: plenum or petcock

#25

Post by ifm61 »

it's in the lap of the gods, just like everything else. if my semi-articulate knuckle dragging methods won't work, i'll have to leave 'er into a shop and put my faith in someone who may or may not give a flyin' one. but that's the nature of the beast when you've reached the apex of your 'limit:' in all its connotations...
ifm61
Billet Alum. Member
Billet Alum. Member
Posts: 281
Joined: Thu Oct 23, 2014 8:44 pm
Location: canada

Re: plenum or petcock

#26

Post by ifm61 »

tonight i thought i'd run out the gas in the float bowls with the petcock off, then when the idle started to dwindle, turn it back on for a second or two, then off again and repeat a couple times.
that thing ran for ages. ages. in the 'off' position. farted, spluttered, and smoked like philip rothman if i revved it still in 'off' but kept running... how much do those float bowls hold for crying out loud? or is there something else amiss...
User avatar
Whiskerfish
President
President
Posts: 36853
Joined: Thu Feb 16, 2006 9:34 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
Location: Norfolk Va

Re: plenum or petcock

#27

Post by Whiskerfish »

Under power like when you leave a gas stop with the petcock off you can usually get 2 or 3 miles before it dies. Not that I have ever done that :oops: :oops: :oops: :oops:
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
redglbx
Gold Member
Gold Member
Posts: 1116
Joined: Tue Jun 02, 2020 8:39 am
Location: NW Indiana,

Re: plenum or petcock

#28

Post by redglbx »

Sure glad that I’ve never done that 🙄🙄😳
Red 1976 oe owner
1976 LTD restored
1980 CBX , in the que, to fix the ignorant heavy handed owner
1981 CBX
1977 CB750 K7
2014 FJR OE owner, sold
1980 GL1100
1984 GL1200 naked
1969 CL350, in the que
User avatar
Lucien Harpress
Honored Life Member
Honored Life Member
Posts: 4077
Joined: Sat Dec 24, 2011 11:41 am
Location: Michigan

Re: plenum or petcock

#29

Post by Lucien Harpress »

Yeah, GL carbs last a while. My KZ? She'll only get about 200 feet.
1997 Valkyrie- Light Cutomization, but Too Busy Riding
1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete

All advice I give is only valid until an expert corrects me.
User avatar
Sagebrush
Run Executive
Run Executive
Posts: 6465
Joined: Wed Aug 15, 2007 10:35 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/album269/
Location: Raleigh, NC

Re: plenum or petcock

#30

Post by Sagebrush »

If it were me in your situation I would find a mechanic with enough skills to remove and replace the carb rack. I would then send the rack to Robin for rebuild. The only thing that you may have to do is synch the carbs once they are reinstalled.
Dean Spalding
Raleigh, NC

"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe." - Albert Einstein

'82 Yellow GL1100
'81 Blue GL1100

My Gallery
My 1100 Build Thread
Post Reply
  • Similar Topics
    Replies
    Views
    Last post

Return to “GoldWing Tech Discussions”