Has anyone come up with a vent/fix for the carb overflow prob. on the 79 carbs? I know newer carbs vent overflow to ground instead of to cyl then oil then bearings Anyone try drilling an overflow hole and vent tube setup?
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Carb overflow
1979 XS1100 Special (Mad Max, OEM) Current
1980 XS1100 Special
1990 V Max
1982 KZ750 LTD Twin
1986 700 FZR Yamaha Fazer (faster then expected)
1979 XS750 Special (my 1st Special)
1974 CB750-Four
Past/pres Car's
1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8Tags: None
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What happened to the new float needle valves you were getting...? I suppose it could be done, but after replacing my Viton tipped needles, I didn't have any reason to. The old VM carbs had brass tubes in the bowls that were higher than the proper fuel level and drained out the bottom.'81 XS1100 SH
Melted to the ground during The Valley Fire
Sep. 12th 2015
RIP
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Originally posted by XS1100_OEM4ME View PostHas anyone come up with a vent/fix for the carb overflow prob. on the 79 carbs? I know newer carbs vent overflow to ground instead of to cyl then oil then bearings Anyone try drilling an overflow hole and vent tube setup?
if the carbs overflow the floats are sunk or set wrong &/or the float needles & seats ain't sealing.
That's what needs to be fixed.
While it's better to have the overflowing gas run out onto the street instead of finding it's way into the oil pan, it's better yet to fix the root problem.Fred Hill, S'toon
XS11SG with Spirit of America sidecar
"The Flying Pumpkin"
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I was not aware that 80+ carbs did anything different if they overflow. My XS400 which has the exact same carbs overflowed into the cylinders if on the center stand, and onto the ground if on the sidestand. Since my 1100's carbs have never done that to me, I don't know for sure what would happen, but if You look at how things sit, on the sidestand the carbs actually tilt slightly away from the engine, on the centerstand they are tilted towards the engine. I think this has more to do with the issue than what carbs are on the bike. Its one of the reasons I almost always park it on the sidestand, and use the centerstand only when working on it.Cy
1980 XS1100G (Brutus) w/81H Engine
Duplicolor Mirage Paint Job (Purple/Green)
Vetter Windjammer IV
Vetter hard bags & Trunk
OEM Luggage Rack
Jardine Spaghetti 4-2 exhaust system
Spade Fuse Box
Turn Signal Auto Cancel Mod
750 FD Mod
TC Spin on Oil Filter Adapter (temp removed)
XJ1100 Front Footpegs
XJ1100 Shocks
I was always taught to respect my elders, but it keeps getting harder to find one.
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Needles
Originally posted by 81xsproject View PostWhat happened to the new float needle valves you were getting...? I suppose it could be done, but after replacing my Viton tipped needles, I didn't have any reason to. The old VM carbs had brass tubes in the bowls that were higher than the proper fuel level and drained out the bottom.1979 XS1100 Special (Mad Max, OEM) Current
1980 XS1100 Special
1990 V Max
1982 KZ750 LTD Twin
1986 700 FZR Yamaha Fazer (faster then expected)
1979 XS750 Special (my 1st Special)
1974 CB750-Four
Past/pres Car's
1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8
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I think whether the gas goes into the cylinders or into the airbox depends entirely on how the carbs sit as far as orientation on the bike. If they slant away from the engine, then any gas that overflows will flow away from the engine into the airbox and onto the ground, if they tilt towards the engine, the the gas will flow into the head, pooling on the intake valves if they are closed, or into the cylinder if they are open. Of course if it gets into the cylinders it's gonna seep past the rings into the oil.
That's why I park on the sidestand, if it's sitting like that, or being ridden, it will pi$$ all over the ground (this assumes level ground of course), but on the centerstand the rear is is raised enough to tilt them toward the front of the bike rather than the slight tilt to the rear they normally have (unless your stopping). Even better, my garage slops slightly towards the door, making them tilt even more toward the back of the bike.Cy
1980 XS1100G (Brutus) w/81H Engine
Duplicolor Mirage Paint Job (Purple/Green)
Vetter Windjammer IV
Vetter hard bags & Trunk
OEM Luggage Rack
Jardine Spaghetti 4-2 exhaust system
Spade Fuse Box
Turn Signal Auto Cancel Mod
750 FD Mod
TC Spin on Oil Filter Adapter (temp removed)
XJ1100 Front Footpegs
XJ1100 Shocks
I was always taught to respect my elders, but it keeps getting harder to find one.
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Kits
Originally posted by prometheus578 View PostUhm... when you did the carbs, you DID put in new STOCK needles, yes?1979 XS1100 Special (Mad Max, OEM) Current
1980 XS1100 Special
1990 V Max
1982 KZ750 LTD Twin
1986 700 FZR Yamaha Fazer (faster then expected)
1979 XS750 Special (my 1st Special)
1974 CB750-Four
Past/pres Car's
1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8
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Most likely you just got a piece of dirt up in there that stuck a float open. You can try adding soem sea foam to the gas, and or, just ride it a bit and then park it and see what you see. But I would be sure to turn the petcocks off every time you park it.Life is what happens while your planning everything else!
When your work speaks for itself, don't interrupt.
81 XS1100 Special - Humpty Dumpty
80 XS1100 Special - Project Resurrection
Previously owned
93 GSX600F
80 XS1100 Special - Ruby
81 XS1100 Special
81 CB750 C
80 CB750 C
78 XS750
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JAT, sometimes after being compressed, the bowl gaskets will hit the bulbs of the brass floats, causing them to hang up. On some kits, they tend to be a bit larger. When rebuilding these carbs, I usually either trim the gaskets down a bit and/or slightly bend the float bulbs in towards the center to prevent any contact between the two. In line fuel filters are a very good idea.2H7 (79) owned since '89
3H3 owned since '06
"If it ain't broke, modify it"
☮
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Carb's
Originally posted by bikerphil View PostJAT, sometimes after being compressed, the bowl gaskets will hit the bulbs of the brass floats, causing them to hang up. On some kits, they tend to be a bit larger. When rebuilding these carbs, I usually either trim the gaskets down a bit and/or slightly bend the float bulbs in towards the center to prevent any contact between the two. In line fuel filters are a very good idea.1979 XS1100 Special (Mad Max, OEM) Current
1980 XS1100 Special
1990 V Max
1982 KZ750 LTD Twin
1986 700 FZR Yamaha Fazer (faster then expected)
1979 XS750 Special (my 1st Special)
1974 CB750-Four
Past/pres Car's
1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8
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Check your floats to make sure none have fuel inside them. Your piece of crud scenario could be the case, but then again, there is a reason I went so far out of my way to find a way to get Viton tipped needle into 70's carbs. I know it goes against everything you stand for, but stock isn't always best. (although with these bike it is MOST of the time).'81 XS1100 SH
Melted to the ground during The Valley Fire
Sep. 12th 2015
RIP
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No
Originally posted by 81xsproject View PostCheck your floats to make sure none have fuel inside them. Your piece of crud scenario could be the case, but then again, there is a reason I went so far out of my way to find a way to get Viton tipped needle into 70's carbs. I know it goes against everything you stand for, but stock isn't always best. (although with these bike it is MOST of the time).1979 XS1100 Special (Mad Max, OEM) Current
1980 XS1100 Special
1990 V Max
1982 KZ750 LTD Twin
1986 700 FZR Yamaha Fazer (faster then expected)
1979 XS750 Special (my 1st Special)
1974 CB750-Four
Past/pres Car's
1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8
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Originally posted by XS1100_OEM4ME View PostThanks Phil, I will def be installing in line filters and re-check gaskets as i will be R/I carbs again I am picky, ANY leak drives me nuts. I was checking out your bike pic's again, NICE. You are picky too
http://www.xs11.com/forum/showthread...ning+defective2H7 (79) owned since '89
3H3 owned since '06
"If it ain't broke, modify it"
☮
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filters
Originally posted by bikerphil View PostYep, NP. Stay away from these filters as they are NFG...
http://www.xs11.com/forum/showthread...ning+defective1979 XS1100 Special (Mad Max, OEM) Current
1980 XS1100 Special
1990 V Max
1982 KZ750 LTD Twin
1986 700 FZR Yamaha Fazer (faster then expected)
1979 XS750 Special (my 1st Special)
1974 CB750-Four
Past/pres Car's
1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8
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