Fuel Starvation

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Fuel Starvation

05 Sep 2013 11:51
#604996
Finally have her running, ( Put about a hundred miles on her last night, tons o fun!)but have a sporadic fuel delivery issue...I have replaced tired original vacuum petcock with the re-pop Zuki unit from Z-1. Anyone had problems with these flowing enough go-juice? I am down to either A: insufficient vacuum to fully open diaphragm due to slightly low compression. or, B: Gas cap vent clogged. Re: A....If I can lay my hands on a vacuum guage, what reading should I have? Re: B. Are there servicable/replaceable parts inside the gas cap, or, could I simply take a blow out nozzle on a compressor to the keyhole? )(I am concerned about tearing something up in there!)Currently am riding on the "prime" setting, but still acts up once in a while. On the "run" (vacuum assist) petcock setting, it wants to sputter every so often. tried running with the tank cap open, seemed to help somewhat, so I am leaning that way...Kinda hate to have this manifest itself at the wrong time, potentially problematic...Spell that "squashed like a bug, LOL!" Thoughts?
1978 KZ650 B2
Former rides...1976 CB360T, 1985 Shadow 700, 1985 GPZ750Turbo

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  • nickleo373
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Re: Fuel Starvation

05 Sep 2013 11:55
#604998
Do you have an inline fuel filter that could be getting clogged up?
1981 KZ550C LTD
"If you ain't first, you're last"

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  • koolaid_kid
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Re: Fuel Starvation

05 Sep 2013 11:56
#604999
They are usually easy to clean, as they normally have two screws inside the cap that you can remove to clean the vent the proper way.
1983 GPz 750
810 Wiseco, Kerker, K&N, DynoJet S3, Accel, Progressive, etc.

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Re: Fuel Starvation

05 Sep 2013 12:07 - 05 Sep 2013 12:10
#605002
Yup, brand new inline filter! Problem is sporadic...Begs yet another question, though...once a filter is clogged, wouldn't it STAY clogged? Fresh professional re-build on the carbs. Just outta the shop.Thanx Koolaid, I have seen the screws inside cap, Reckon I'll take me a little look-see!Thanx again, all!
1978 KZ650 B2
Former rides...1976 CB360T, 1985 Shadow 700, 1985 GPZ750Turbo
Last edit: 05 Sep 2013 12:10 by Grumpy Ole Artist. Reason: Response to subsequent suggestion

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  • koolaid_kid
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Re: Fuel Starvation

05 Sep 2013 12:40
#605007
Yes, it would stay clogged. Did you purchase the proper type of filter? One for a gravity feed system, such as a lawn tractor, is what you want.
1983 GPz 750
810 Wiseco, Kerker, K&N, DynoJet S3, Accel, Progressive, etc.

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  • Grumpy Ole Artist
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Re: Fuel Starvation

05 Sep 2013 13:01
#605012
My mechanic used the standard filter he always uses for bikes, quads, etc. (And he IS one of the good ones, LOL!)Thanx, though!
1978 KZ650 B2
Former rides...1976 CB360T, 1985 Shadow 700, 1985 GPZ750Turbo

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  • Beaner242
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Re: Fuel Starvation

05 Sep 2013 14:11
#605025
Filter on the petcock itself smashed? Had this happen once on a bike.
1982 KZ1000K LTD Chopper

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Re: Fuel Starvation

05 Sep 2013 14:23 - 05 Sep 2013 14:27
#605032
Brand new re-pop suzuki petcock, MUCH slimmer than original was, and a MUCH easier unit to get into tank, in-tank filter is perfect...Good thought, though! Can't wait to get home and try taking apart the tank cap...see what's what under there! (All right, mebbe just a SHORT country roads ride before I disable her...LOL!) Anything gonna jump out at me from behind those two screws under the filler cap? (Springs, etc)
1978 KZ650 B2
Former rides...1976 CB360T, 1985 Shadow 700, 1985 GPZ750Turbo
Last edit: 05 Sep 2013 14:27 by Grumpy Ole Artist. Reason: Added further question

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  • 650ed
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Re: Fuel Starvation

05 Sep 2013 17:04 - 05 Sep 2013 17:21
#605056
Assuming your gas cap looks like this:

Attachment 00007.jpg not found



the underside should look like this:

Attachment 00001_2013-09-05-3.jpg not found



if you remove the 3 screws you will find this:

Attachment 00002_2013-09-05.jpg not found



if you remove that center screw the metal piece with the brown papery thing comes off. Here's what that piece looks like from the underside:

Attachment 00003_2013-09-05.jpg not found



There is a spring under that piece; it sits between it and the underside of the gas cap like this:

Attachment 00004_2013-09-05.jpg not found



It's all pretty straight forward to take apart and re-assemble. If you get curious and decide to take apart the latch mechanism be sure to take note of how the spring that controls the little chrome keyhole cover is positioned. Here's what it looks like:

Attachment 00006.jpg not found



Here are the pieces that comprise the latch mechanism. If you take it apart take a couple pictures as you go along so you can get all the little parts back where they belong. Ed

Attachment 00005_2013-09-05.jpg not found

1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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Last edit: 05 Sep 2013 17:21 by 650ed.
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Re: Fuel Starvation

05 Sep 2013 17:21
#605064
Could not IMAGINE anything more helpful! Color pics, even... the FSM hasn't got those! Thanx so much! (Hopefully it's a spider's nest in there, or something visible!)LOL! Thanx again!
1978 KZ650 B2
Former rides...1976 CB360T, 1985 Shadow 700, 1985 GPZ750Turbo

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  • slayer61
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Re: Fuel Starvation

05 Sep 2013 18:18 - 05 Sep 2013 18:19
#605079
650ed wrote: Assuming your gas cap looks like this:


the underside should look like this:


if you remove the 3 screws you will find this:


if you remove that center screw the metal piece with the brown papery thing comes off. Here's what that piece looks like from the underside:


There is a spring under that piece; it sits between it and the underside of the gas cap like this:


It's all pretty straight forward to take apart and re-assemble. If you get curious and decide to take apart the latch mechanism be sure to take note of how the spring that controls the little chrome keyhole cover is positioned. Here's what it looks like:


Here are the pieces that comprise achmentthe latch mechanism. If you take it apart take a couple pictures as you go along so you can get all the little parts back where they belong. Ed


Ed do you take your bike apart every time somebody has a question about this or that? ;) That's VERY kind of you... We appreciate it! Paul
Don't be ridiculous! It's only a flesh wound!

[strike]Wife's little bike... 1984 GPZ 550 Kerker and DynaJet stage I kit[/strike]
Wife's BIG bike......[strike] 1981 GPZ 1100 Kerker and [strike]factory FI[/strike] Mikuni RS34s W/ K&N pods[/strike] SOLD
Last edit: 05 Sep 2013 18:19 by slayer61. Reason: jus cuz

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Re: Fuel Starvation

05 Sep 2013 18:20
#605081
Of course. ;) Thank goodness no one has asked about the crankshaft! :woohoo: :woohoo: Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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