Author Topic: Johnie's 76 GL1000 Sulfur Yellow Build  (Read 21971 times)

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Offline Johnie

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #525 on: July 06, 2024, 05:57:15 PM »
I have a question for you GL1000 guys. I have to change the petcock on my 76...quite different than all those CB750 ones I'ver done. My original drips fast on the off position. My service manual in the fuel section says nothing of this part replacement. Can you enlighten me on what I'm going to find like how do the 2 lines enter the petcock? I decided to buy new as I have not had much luck rebuilding them. Thanks much fellas...greatly appreciate all the help.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline Don R

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #526 on: July 06, 2024, 08:02:20 PM »
 If I recall correctly, the 2 lines are welded to the inside of the tank, protrude a tiny bit maybe and the petcock seals over them. So, it's just a bolt-on deal like a regular gas tank. 
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline BenelliSEI

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #527 on: July 07, 2024, 06:09:37 AM »
If I recall correctly, the 2 lines are welded to the inside of the tank, protrude a tiny bit maybe and the petcock seals over them. So, it's just a bolt-on deal like a regular gas tank.

Also from memory, Don’s description is spot on.

Offline Johnie

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #528 on: July 07, 2024, 07:23:45 AM »
Excellent...I didn't want to go into it blind. Mine is the OE with the screws. I saw some guys have the rivets in place of the screws. Thanks again...should fire this up soon. The petcock should be into my dealer this coming week. Got all the wife's projects done...for now...LOL
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline Don R

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #529 on: July 07, 2024, 07:45:26 AM »
 It should be an easy swap.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline MauiK3

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #530 on: July 07, 2024, 07:48:00 AM »
We are all waiting to see/hear results.
1973 CB 750 K3
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Offline Lucien Harpress

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #531 on: July 11, 2024, 09:07:51 AM »
Yup, 1000 petcocks are super simple.  As stated, the inlet pipes are welded (brazed, actually) into the tank itself, so everything under the petcock is flush, with just 4 holes- two screw holes, two fuel holes.  Just be sure there's no paint on the sealing surface and you're good.

The petcock itself is super simple too.  Once you get the little front plate off (you have the version with screws, so that's the hardest part done) you've got the lever, a little wavy spring washer, MAYBE another flat washer, and the rubber donut seal.  No real "gotchas" anywhere.
-1970 CB750 K0
-1980 KZ1300
-1976 Yellow GL1000
-1965 CA77 "Dream"
-1997 Valkyrie
-1975 Velosolex

Offline Johnie

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #532 on: July 11, 2024, 10:48:16 AM »
Gosh that was the easiest petcock I ever installed! No leaks either. Thanks guys. Ordered a new gas cap gasket and currently have the cap in Evaporust. Will clear the cap vents too. Then once this heat breaks I will move the bike outside and fire it up. I bought a battery operated gas syphon unit at Harbor Freight last week. That thing is slick and was $12 cheap. No more mouth syphoning for me...LOL.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline BenelliSEI

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #533 on: July 11, 2024, 01:47:40 PM »
Have you examined your fuel pump? My neighbours 1975 ‘wing was acting strangely last week, like it was running out of gas. The rubber diaphragm had turned to sludge…. He hadn’t ridden it for about five years. Ran well for a few days and then the pump died. No individual parts available, he’s waiting for a new one.

After he order/paid for one it occurred to me that a small, electric Facet pump used to be a common modification…… kept my mouth shut, but worth remembering if yours goes south.

Offline Johnie

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #534 on: July 11, 2024, 02:27:40 PM »
I have not examined my fuel pump. It hasn't been run for 20 years. No fuel in it yet. It was stored dry. Info I found on the NGW site says rebuilding it is "not a job for a beginner". I don't have the machinery or set up to do what is required to rebuild mine. Checked with my dealer and I can still get the OEM pump so I'm going to go that route. At least to have it in my stock. Here's a question for you guys...if the diaphram is bad will it get rubber junk into my nice clean carbs? Or is there no way that will happen if I decide to try it as is first.
« Last Edit: July 11, 2024, 03:42:59 PM by Johnie »
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline BenelliSEI

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #535 on: July 11, 2024, 06:50:23 PM »
Johnie….. The pump should easily drive gas through a nice big automotive style filter (diaphragm pumps blow much harder than they suck). I’d stick a clear one between the pump and the carbs and see what comes out?

Leave it on for a while. My neighbours bike ran great for several days and then the pump dissolved. Like yours, it sat dry for quite a while.

Offline grcamna2

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #536 on: July 11, 2024, 08:38:33 PM »
Install the NOS pump and you're done  ;)
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Lucien Harpress

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #537 on: July 12, 2024, 02:24:58 AM »
The stock pumps are pretty bulletproof.  Even so, if they go bad your first indication is usually fuel staining down a weep hole on the backside.  As for the diaphragm disintegrating and ruining your carbs?  Possible I'm sure, but I've never seen anyone have that problem.  The fact you can get replacement pumps new is a huge bonus.

(Sidebar, my yellow GL actually came with an electronic fuel pump.  They're nice in the fact you don't need to spin the motor over to "prime" the pump.  That said, I did swap mine back to the original cam-driven pump for originality, and both work just fine.)
-1970 CB750 K0
-1980 KZ1300
-1976 Yellow GL1000
-1965 CA77 "Dream"
-1997 Valkyrie
-1975 Velosolex

Offline Johnie

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #538 on: July 12, 2024, 11:25:06 AM »
Hey John thanks for steering me to check the fuel pump diaphragm. Definitely cracked. Glad I got the new OE coming.
« Last Edit: July 12, 2024, 11:34:19 AM by Johnie »
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline BenelliSEI

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #539 on: July 12, 2024, 11:43:57 AM »
Good you checked! My buddy’s probably looked like that, before it dissolved.

Offline Don R

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #540 on: July 12, 2024, 12:28:16 PM »
  Aside from the size, that looks just like the diaphragm I just took out of my Holley mechanical fuel pump from my 40 chevy. It was both clogging the carb and leaking gas. Last year all of the fuel lines needed replacing so I kind of saw it coming.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline BenelliSEI

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #541 on: July 13, 2024, 05:57:05 AM »
  Aside from the size, that looks just like the diaphragm I just took out of my Holley mechanical fuel pump from my 40 chevy. It was both clogging the carb and leaking gas. Last year all of the fuel lines needed replacing so I kind of saw it coming.

What’s annoying is you can’t buy parts. Only the complete pump.

Offline grcamna2

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #542 on: July 13, 2024, 07:35:55 AM »
  Aside from the size, that looks just like the diaphragm I just took out of my Holley mechanical fuel pump from my 40 chevy. It was both clogging the carb and leaking gas. Last year all of the fuel lines needed replacing so I kind of saw it coming.

What’s annoying is you can’t buy parts. Only the complete pump.

Yes.  >:(
I could only hope that someone who has worked on Honda cars,boats,etc. might recognize that pump and have a different parts break-down which shows the diaphragm as a separate part #.  ::)
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline MauiK3

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #543 on: July 13, 2024, 07:47:17 AM »
There has to be some equivalent somewhere!
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Lucien Harpress

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #544 on: July 13, 2024, 07:58:48 PM »
The naked Goldwing guys have been looking into this for a while, and while they can be rebuilt, it involves getting a diaphragm from a larger pump, cutting it down, and transferring over the central metal parts.  This involves drilling a rivet rather precisely, which is where most of the difficulty lies.  Even then, the rebuilt pumps have a higher than average tendency to leak.

End of the day, it's a lot of work to get a so-so result, especially when brand new pumps are still available from Honda.  Guys who want a working fuel pump for cheap usually thrown on an electric one, and guys sticking to period correctness either spring for the new one, or grab used off eBay for $20.
-1970 CB750 K0
-1980 KZ1300
-1976 Yellow GL1000
-1965 CA77 "Dream"
-1997 Valkyrie
-1975 Velosolex

Online scottly

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #545 on: July 13, 2024, 08:46:34 PM »
When a mechanical fuel pump leaks, it can pump gas right into the crankcase, diluting the oil big time. :o
Don't fix it if it ain't broke!
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Offline Johnie

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #546 on: July 14, 2024, 05:09:20 PM »
Those are excellent write-ups about the fuel pump issue guys.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline Johnie

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #547 on: July 15, 2024, 02:51:54 PM »
Got the new fuel pump on and noticed below it on the back of the head is an open threaded hole that goes back and inch and stops. Any idea what this is and is it an issue?
« Last Edit: July 15, 2024, 02:53:27 PM by Johnie »
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline Lucien Harpress

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #548 on: July 15, 2024, 03:42:24 PM »
The head castings are identical, and can be swapped left/right.  I think the timing belt plate gets screwed to that if it was on the other side.  Nothing to worry about.

-1970 CB750 K0
-1980 KZ1300
-1976 Yellow GL1000
-1965 CA77 "Dream"
-1997 Valkyrie
-1975 Velosolex

Offline Johnie

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Re: Johnie's 76 GL1000 Sulfur Yellow Build
« Reply #549 on: July 15, 2024, 03:54:32 PM »
Oh man thanks Lucien. I thought maybe it was for some aftermarket accessory or something.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA