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Author Topic: Pre efi - GV 250 Fuel Lines  (Read 463 times)

hogrider

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Pre efi - GV 250 Fuel Lines
« on: May 28, 2018, 05:11:26 PM »

Newbie here, trying to assemble a motorcycle that was disassembled by someone else, no pics to go by, read the manual already.

I cant get it to start, spark is there, plugs are moist with gas, engine is cranking

I cant figure out where a black fuel line ~170mm connects, it has a clip on one side.

- The fuel tank bleeder is connected
- The Carb bleeder is connected via Y between both carbs
- AIS is removed, front cylinder to AIS is blocked off
- Crankcase breather is connected

I have three gray fuel lines connected;
small gray with spring -> fuel filter -> fuel pump inlet
170mm gray from P on fuel pump to second cylinder for pulse
170 mm gray from Fuel pump out to Carb Inlet at Y

Anyone kind enough to share a picture of how these lines are routed on their motorcycle?

Thanks

I wasn't able to find any pictures in a previous thread, so a new one :)
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Christianleon266

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Re: Pre efi - GV 250 Fuel Lines
« Reply #1 on: May 28, 2018, 05:30:23 PM »

http://korider.com/index.php?topic=29458.0

You need Air, Fuel, Spark, Compression and timing to make an engine run, so look at timing and compression if all else seems fine.

That being said, to answer your question regarding lines, The carbs have vent lines coming out of the top of the bowls (Or between carbs near the top of the diaphragm, depends on year), a single fuel inlet towards the rear cylinder, and drain lines at the bottom of the bowls. Vent lines go to atmosphere (or air filter, i run pods.), drain to bottom of bike and inlet to the outside of the pump. The pump lines consist of an inlet coming from the fuel filter/ tank, Vacuum line from carb boot, and outlet to carbs. AIS is deleted, so no vacuum lines or air lines should be connected.

Your description leads me to believe that you have your fuel pumping fuel to the vent lines at the "Y", rather than the single inlet nipple at the end of the rear cyl. carb, potentially flooding the carbs and cylinders.
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2007 Kawasaki KX250F
1984 Yamaha Virago
1982 Honda V45 Sabre
1996 Kawasaki ZX6R
2009 Kawasaki Ninja 250
1984 Honda V65 Magna (Favorite)
1982 Kawasaki KZ750E
2005 Suzuki M50
1983 Honda Goldwing Aspencade
2007 Hyosung GT250R
1991 Honda ST1100 (current)

hogrider

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Re: Pre efi - GV 250 Fuel Lines
« Reply #2 on: May 28, 2018, 06:43:27 PM »

Thank you  ;D

Appreciate the quick feedback, I have attached left and right sides with the fuel tank removed.

From the left side, the thin bleeder lines from carb go down on left side, you are not referring to those, correct?



From Right side, you are saying that the gray line should connect to the carb on brass inlet, understood.
So the plastic T on right side connects to where? Is that also a bleeder line, that I should connect the long black line to?
 Where should the other end of the carb T be connected?


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Christianleon266

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Re: Pre efi - GV 250 Fuel Lines
« Reply #3 on: May 28, 2018, 07:01:11 PM »

Blue is carburetor float bowl vent lines, should route to right and go to atmosphere (connect to nothing.)
Red is fuel line from carb, to pump, to filter then tank.
Purple is vacuum lines for AIS, petcock, and pulse pump.
Green is drain from bowls.
Yellow is AIS air supply line.

Credit to Caligonetx for his photo, I do not have a camera otherwise I would take a photo of my carbs.

« Last Edit: May 28, 2018, 07:10:38 PM by Christianleon266 »
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2007 Kawasaki KX250F
1984 Yamaha Virago
1982 Honda V45 Sabre
1996 Kawasaki ZX6R
2009 Kawasaki Ninja 250
1984 Honda V65 Magna (Favorite)
1982 Kawasaki KZ750E
2005 Suzuki M50
1983 Honda Goldwing Aspencade
2007 Hyosung GT250R
1991 Honda ST1100 (current)

hogrider

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Re: Pre efi - GV 250 Fuel Lines
« Reply #4 on: May 28, 2018, 11:37:20 PM »

Thanks again for the image, I was able to fix the issue I had before.

Switched lines, black is fuel pump output -< carb input

Float drains connected via T to Gray bleeder

Added some Seafoam via dropper to each cylinder and added seafoam to fuel pump, getting partial ignites/misfires ...

Checked spark plugs, sparks are strong, around 440 rpm

still cant get the firing to sustain, its close, yet no idea why its not starting
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Christianleon266

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Re: Pre efi - GV 250 Fuel Lines
« Reply #5 on: May 29, 2018, 12:26:45 AM »

Check for vacuum leaks, any holes at the intake boots or vacuum lines. Clean the carbs too, should be a given with any bike. I don't see any boot clamps on those carb venturis either in the photo, or an air filter. Try choke, no choke, covering air holes, etc.
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2007 Kawasaki KX250F
1984 Yamaha Virago
1982 Honda V45 Sabre
1996 Kawasaki ZX6R
2009 Kawasaki Ninja 250
1984 Honda V65 Magna (Favorite)
1982 Kawasaki KZ750E
2005 Suzuki M50
1983 Honda Goldwing Aspencade
2007 Hyosung GT250R
1991 Honda ST1100 (current)

hogrider

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Re: Pre efi - GV 250 Fuel Lines
« Reply #6 on: May 29, 2018, 11:31:23 PM »

Carbs are clean, gas mix spraying out of cylinder with the spark plugs off when cranking.

The boot clamps are on, somehow did not show with the camera angle. The airbox side mount on carb was loose and I could not get enough leverage to get the airbox to slide lower.

So vacuum is one line to fuel pump from rear carb boot, and nothing from front cylinder.

Got the rear cylinder to fire with the front open and airbox off, (front cylinder is misfiring so was choking the rear via airbox)

To get the airbox on, I had to remove the mounting bolts and lower the engine to get carb and airbox together on it.

Is there a less cumbersome way to do that?

After this I plan to take the front head apart and see if the cams are aligned properly.  I thought the alignment was to spec with tappet clearances (~0.12mm in, 0.24mm exhaust, spark plugs new NGKs with 0.8mm clearance) but will redo everything as I cant quite figure it out.

After cleaning and lapping the valves, I had aligned rear cylinder to TDC and then the front, the cam lobe positions were similar in degrees, but with the backpressure I see through the front carb, suspect that is not the case.

Are the front cam lobe positions different from rear cylinder? I got ` (ex) ' (in) positions if I remember correctly 16 pins apart ...
« Last Edit: May 30, 2018, 01:50:18 AM by hogrider »
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Christianleon266

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Re: Pre efi - GV 250 Fuel Lines
« Reply #7 on: May 30, 2018, 02:01:27 AM »

What does a compression test say? Does your bike have a manual petcock (Knob to turn off or on) or a vacuum petcock (square looking diaphragm with vacuum port on top).

Also, now that I think about it, fuel shouldn't really be spraying out of the spark plug holes. Could be too rich. You crank long enough on a running bike with the kill switch on  and youll have  a no start for awhile.

I'm aiming towards compression now, or an improper fuel mixture next.
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2007 Kawasaki KX250F
1984 Yamaha Virago
1982 Honda V45 Sabre
1996 Kawasaki ZX6R
2009 Kawasaki Ninja 250
1984 Honda V65 Magna (Favorite)
1982 Kawasaki KZ750E
2005 Suzuki M50
1983 Honda Goldwing Aspencade
2007 Hyosung GT250R
1991 Honda ST1100 (current)

hogrider

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Re: Pre efi - GV 250 Fuel Lines
« Reply #8 on: May 30, 2018, 02:41:08 AM »

Don't have a compression test tool.

Manual petcock, have some fresh gas in tank and petcock set to reserve position.

 The fuel spray was due to my adding a few cc of gas/seafoam mix to carb to get the engine to start firing,  richer than what carb would feed (to isolate carb flow), and was able to get the ignition started and vacuum line (connected to rear cylinder) to get the pulse for gas into carb (working ok)

Don't use the kill switch, (always leave it on, don't hold starter either once its running)

Covering front carb inlet even with spark plug out provides a considerable back pressure, same for spark plug cavity.

With spark plug in front cylinder, the smoke was coming out from the carb backwards, causing me to suspect the valve timing.

Would compression cause a backup in carb from cylinder?

I didn't have the idle screw in far, so the rear cylinder was running at a higher rpm (like a broken throttle wire, will calibrate that later)
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Christianleon266

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Re: Pre efi - GV 250 Fuel Lines
« Reply #9 on: May 30, 2018, 02:50:08 AM »

Not timing, but poor clearances, or no clearances at all. If you have tight or no clearance on the valves, you get a valve that potentially never seats, which translates to no compression, no running and pressure on the intake where air is pushed back up.

Leave the spark plug in, carbs off and spark plug wire off and grounded somewhere (dont want a backfire on your hand lol). Place your hand on the intake, relatively close but not sealed. should feel some suction but no or very very little back pressure.

Check your clearances, there are plenty of threads on how to do it floating around here.
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2007 Kawasaki KX250F
1984 Yamaha Virago
1982 Honda V45 Sabre
1996 Kawasaki ZX6R
2009 Kawasaki Ninja 250
1984 Honda V65 Magna (Favorite)
1982 Kawasaki KZ750E
2005 Suzuki M50
1983 Honda Goldwing Aspencade
2007 Hyosung GT250R
1991 Honda ST1100 (current)

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