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many owners have the fuel petcock issue with the octy series design. the diaphram had 4 holes in it. what is it that seals the on and reserve setting so it doesnt leak when disco'd from fuel lines and tank off bike. if it works off of vacuum, what seals it if it has open holes. what is it that normally needs replaced? i need to take mine apart. the last time i had it apart, the diaphram looked good, no rips or holes. i dont think its sealing correctly. also i was filling up the float bowls on one side cause when i disco'd the lines to re-orient them on carb 1, 2, the prime line leaked all the fuel out. yes i am aware that prime dumps fuel into the bowls, but they are connected to the octy? i guess i just dont get it!
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Last edited by mjpxs11sh; 07-24-2011, 09:52 AM.Max
81 XS1100SH Black Beast Mutt
Kerker 4/1
stock carbs and air box.
78 headlite, handle bars,
1 set of ea-160/85mph guages,
crash bars, cruise control
Other 2 Wheelers
78 XS1100E jet kit, Kerker 4/1, air pods, jet kit-RIP
94 CBR1000F jet kit,Two Bros pipe, K&N Filter -
The "PRIME" hoses are supposed to bypass the "octy". This is so you can fill the bowls before starting the bike. If plumbed correctly, once the engine starts, vacuum should open the "octy" to allow fuel to flow in the "ON" position.
"ON" taps run through the "octy", "PRIME" taps bypass the "octy".
Marty (in Tampa)Marty (in Mississippi)
XS1100SG
XS650SK
XS650SH
XS650G
XS6502F
XS650E -
There should be a fuel line diagram either on the underside of the seat or one of the sidecovers IIRC. If you don't have a manual, find a post by Catatonic Bug and download the manual from his link. It will be in there...
Yeah, that wasn't one of their better ideas....Fast, Cheap, Reliable... Pick any two
'78E original owner - resto project
'78E ???? owner - Modder project FJ forks, 4-piston calipers F/R, 160/80-16 rear tire
'82 XJ rebuild project
'80SG restified, red SOLD
'79F parts...
'81H more parts...
Other current bikes:
'93 XL1200 Anniversary Sportster 85RWHP
'86 XL883/1200 Chopper
'82 XL1000 w/1450cc Buell, Baker 6-speed, in-progress project
Cage: '13 Mustang GT/CS with a few 'custom' touches
Yep, can't leave nuthin' alone...Comment
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Crazy Steve
thanx Marty and Steve, i pulled the tank and heres what i have:
off=no flow
on=no flow
pri=frt outlet flow
res=rear outlet flow
same on both petcocks. isnt the fuel supposed to be no flow in res?
last nite i had fuel in the air box, looks like carb #2, cause i left the prime on for carbs #1, #2. do i have a needle seat issue? it should shut the fuel off, right? i hate to take those carbs back off, butMax
81 XS1100SH Black Beast Mutt
Kerker 4/1
stock carbs and air box.
78 headlite, handle bars,
1 set of ea-160/85mph guages,
crash bars, cruise control
Other 2 Wheelers
78 XS1100E jet kit, Kerker 4/1, air pods, jet kit-RIP
94 CBR1000F jet kit,Two Bros pipe, K&N FilterComment
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With the tank off and no lines connected, you should get no flow when 'off', flow out the front hose connection on 'prime', and flow out the rear connection on either 'on' or 'reserve'. No flow in the 'on' position means the fuel level in the tank is too low.
And yes, if you're getting fuel in the airbox, the float valves are leaking...
Fast, Cheap, Reliable... Pick any two
'78E original owner - resto project
'78E ???? owner - Modder project FJ forks, 4-piston calipers F/R, 160/80-16 rear tire
'82 XJ rebuild project
'80SG restified, red SOLD
'79F parts...
'81H more parts...
Other current bikes:
'93 XL1200 Anniversary Sportster 85RWHP
'86 XL883/1200 Chopper
'82 XL1000 w/1450cc Buell, Baker 6-speed, in-progress project
Cage: '13 Mustang GT/CS with a few 'custom' touches
Yep, can't leave nuthin' alone...Comment
-
allright, that makes sense. thats how much fuel i guess i lost. so when the bike is not running and no vacuum, the fuel is only shut off at the octy, not at the petcock. i was under the impression from other posts that there should be no flow at petcock in the on/res position, tank off. i think i need to give my brain a break!
Max
81 XS1100SH Black Beast Mutt
Kerker 4/1
stock carbs and air box.
78 headlite, handle bars,
1 set of ea-160/85mph guages,
crash bars, cruise control
Other 2 Wheelers
78 XS1100E jet kit, Kerker 4/1, air pods, jet kit-RIP
94 CBR1000F jet kit,Two Bros pipe, K&N FilterComment
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That's true if you have a standard tank, as those have the vacuum valve built-in to the petcock. Much less complicated design, but unfortunately those won't fit the special tank....Originally posted by mjpxs11sh View PostI was under the impression from other posts that there should be no flow at petcock in the on/res position, tank off. i think i need to give my brain a break! 
Fast, Cheap, Reliable... Pick any two
'78E original owner - resto project
'78E ???? owner - Modder project FJ forks, 4-piston calipers F/R, 160/80-16 rear tire
'82 XJ rebuild project
'80SG restified, red SOLD
'79F parts...
'81H more parts...
Other current bikes:
'93 XL1200 Anniversary Sportster 85RWHP
'86 XL883/1200 Chopper
'82 XL1000 w/1450cc Buell, Baker 6-speed, in-progress project
Cage: '13 Mustang GT/CS with a few 'custom' touches
Yep, can't leave nuthin' alone...Comment
-
CORRECT! Octy is the shutoff point.Marty (in Mississippi)
XS1100SG
XS650SK
XS650SH
XS650G
XS6502F
XS650EComment
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Crazy Steve
ok! youve just thawed out my brain freeze! ya know when u have a bunch of guys and their ideas, u have to interpret all of the things they say, and then analyze ur own situation and make an educated guess of what makes sense, brain freeze, sometimes. thanx Guru, u the man! ur not Crazy, its the rest of the world.
and thanx Marty!Last edited by mjpxs11sh; 07-24-2011, 12:05 PM.Max
81 XS1100SH Black Beast Mutt
Kerker 4/1
stock carbs and air box.
78 headlite, handle bars,
1 set of ea-160/85mph guages,
crash bars, cruise control
Other 2 Wheelers
78 XS1100E jet kit, Kerker 4/1, air pods, jet kit-RIP
94 CBR1000F jet kit,Two Bros pipe, K&N FilterComment
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