How do you route fuel and vac lines when using fuel on/off valve?

Jesush91 · 09-01-2017, 12:10 AM

I would love a picture as to how I should route fuel and vacuum lines on my gy6 150cc scooter. Its a 2005 model vento phantom r4i clone. I recently picked it up for $30 and put in a new top end as the scooter had no compression when i got it. Also, if i may add i have a k&n type cone filter because the scooter didn't come with a stock air box. To further add to the mix, the scooter came with a free flowing exhaust. I tried turning on the scooter but its hard to start and when it does start it runs at high fluctuating rpm's then dies off eventually as i try calming it down by turning idle screw clockwise. This is how things are routed right now. I deleted the fuel petcock and in its place put a fuel on/off valve, and i have the vac hose from the valve cover blocked off using a screw. I know little about these and would like to know how to get it running right. If i may add, yes that's a new brand carb and the main jet is a size 115.
Also, i dont know how to add a picture here. Please help me figure that out

Jesush91 · 09-01-2017, 12:56 AM

Since i cant upload my picture from my iphone, i will describe how i have things set up. From the fuel tank runs the gas hose to the fuel on/off valve. From the valve the hose goes through a brass sintered fuel filter. From the filter the hose goes to the fuel inlet on the carb. As for vacuum hoses, the vac hose from the carb i routed it to go to the intake manifold barb. Finally, i plugged the vac hose running from the valve cover.

Roscoe · 09-01-2017, 12:47 PM

This explains it pretty well. but I'd do a home made catch can or just a hose leading down low for the crankcase ventilation. The engine crankcase needs a vent or it will build up pressure and cause oil leaks or force the oil past internal seals.... and you don't want that.

Jesush91 · 09-09-2017, 12:50 AM

Ok, so i checked that all bolts were tight on the engine. All the gaskets are new. Engine will only run if i spray in some seafoam deep creep penetrating lube into the intake and will rev, but as soon as i let off the throttle completely, it dies. The scooter does same exact thing with the old carb it had on it that I meticulously cleaned and with a brand new carb too. So i know it is a fuel flow issue, and from what I've worked on 2 stroke dirt bikes, it's probably running too lean. I'm new to 4 stroke engines. Regularly, this condition in a 2 stroke tells me either the carb is bad or there is an air leak. Engine does not leak oil and all bolts are tight and the gaskets are new. This has me scratching my head quite a bit. Some help would greatly be appreciated

rks · 09-09-2017, 09:28 AM

Easy enough to pull fuel line from barb on the carb, then open your manual petcock and check the flow rate. Could be some crud in the tank, restricting the flow.

I assume that you adjusted the valve gaps after installing your top end kit.

As Roscoe eluded.......no vac lines attach to the valve cover.....that is a breather hose, and must remain open.

Jesush91 · 09-09-2017, 06:09 PM

Quote:

Originally Posted by rks

Easy enough to pull fuel line from barb on the carb, then open your manual petcock and check the flow rate. Could be some crud in the tank, restricting the flow.

I assume that you adjusted the valve gaps after installing your top end kit.

As Roscoe eluded.......no vac lines attach to the valve cover.....that is a breather hose, and must remain open.

1。Fuel flow looks good but hell im not the scooter i dont know how much it needs. Im using a sintered fuel filter one of those see thru ones with the filtering filament being a ton of teeny little brass balls. I will remove the filter and see how that affects the scooter, will report results when i work on scooter after work today.

2。valve clearances for both intake and exhaust were set by me at .005" when i installed the top end kit.

3。i simply led a hose from valve cover all the way to somewhere above the gas tank as i saw thats what people do in place of installing an oil catch can.

Jesush91 · 09-14-2017, 06:14 PM

So, i removed the fuel filter and connected fuel hose from tank straight to the carb and the scooter ran the same. Since fuel hose is see through, i saw that i was getting good flow of gas no bubbles in the libe so the filter i had in place wasn't restrictive and there appear to be no blockages of fuel to limit flow. So scooter will only start if i spray lubricating oil in the intake and keep the throttle engaged. If i let go at all, the scooter dies and will not restart unless i throw in another squirt of penetrating oil spray. Problem has me real confused especially since i invested a good chunk of cash on the top end kit plus in valuable time to carefully install it

Roscoe · 09-15-2017, 08:58 AM

sounds like a vacuum leak and/or a bad carburetor. Might want to also check the valve clearance again and make sure the camshaft timing is spot on. Simplified the carburetor has four modes...cold start, idle, mid-range and power. I'd be checking the cold start enrichment and idle speed/fuel mixture adj. If that doesn't get it running right try cleaning the carb and if that doesn't work ... new carburetors are cheap for GY6s.

Jesush91 · 02-28-2018, 07:28 PM

Quote:

Originally Posted by Roscoe

sounds like a vacuum leak and/or a bad carburetor. Might want to also check the valve clearance again and make sure the camshaft timing is spot on. Simplified the carburetor has four modes...cold start, idle, mid-range and power. I'd be checking the cold start enrichment and idle speed/fuel mixture adj. If that doesn't get it running right try cleaning the carb and if that doesn't work ... new carburetors are cheap for GY6s.

ok, so it's been quite a while and after tinkering this vento r4i clone still isn't running. So, you mention timing maybe being an issue. That's the part that confuses me because im able to neatly make sure the camshaft middle hole is pointing straight up when i place the chain over it no sweat, however, I'm not sure if I'm getting the crank exactly where it needs to be.

When i attempt to put the flywheel right on the T mark, what happens is the flywheel moves a little clockwise, seemingly because the way the crankshaft weights are, gravity wants to pull them down so I can't get the flywheel to stay exactly with the T mark being pointed at by the notch on the flywheel cover to point exactly at it. So, knowing what TDC looks like, i try my best to get the piston exactly at its topmost position before the crankshaft wants to move the piston a couple degrees when I let go of the flywheel.

What does any one suggest is going on? In youtube videos the guys that do the timing portion put the flywheel in perfect position with the notch pointing straight at the T mark without the crank moving right after they put it in that position.

Jesush91 · 03-06-2018, 10:06 PM

One thing is for sure. When I get projects, I like to finish them. I refuse to junk this gy6 scooter. I want to make it run right because I need to learn and be able to move on and get this scooter scooting on out the door.

Jesush91 · 03-07-2018, 02:25 PM

Ok, so to get the crank from moving from the T mark, i jammed a flathead screwdriver between the nub on the flywheel case and the flywheel to keep flywheel from moving with the nub pointing RIGHT at the T line on the flywheel. After that I decided to remove the chain off the camshaft gear and reposition it after getting the cam gear to be pointing in the right middle and the 2 smaller ones line up with the head.

Tried starting up the scooter using the starter, no luck. Tried spraying wd-40 in intake manifold, nothing. New top end so compression is there. Spark is strong. Fuelis there. No firing though at all now. This has me puzzled.

09-01-2017, 12:56 AM	#2
Jesush91 Join Date: Aug 2017 Posts: 9	Since i cant upload my picture from my iphone, i will describe how i have things set up. From the fuel tank runs the gas hose to the fuel on/off valve. From the valve the hose goes through a brass sintered fuel filter. From the filter the hose goes to the fuel inlet on the carb. As for vacuum hoses, the vac hose from the carb i routed it to go to the intake manifold barb. Finally, i plugged the vac hose running from the valve cover.
	0

09-09-2017, 12:50 AM	#4
Jesush91 Join Date: Aug 2017 Posts: 9	Ok, so i checked that all bolts were tight on the engine. All the gaskets are new. Engine will only run if i spray in some seafoam deep creep penetrating lube into the intake and will rev, but as soon as i let off the throttle completely, it dies. The scooter does same exact thing with the old carb it had on it that I meticulously cleaned and with a brand new carb too. So i know it is a fuel flow issue, and from what I've worked on 2 stroke dirt bikes, it's probably running too lean. I'm new to 4 stroke engines. Regularly, this condition in a 2 stroke tells me either the carb is bad or there is an air leak. Engine does not leak oil and all bolts are tight and the gaskets are new. This has me scratching my head quite a bit. Some help would greatly be appreciated
	0

09-14-2017, 06:14 PM	#7
Jesush91 Join Date: Aug 2017 Posts: 9	So, i removed the fuel filter and connected fuel hose from tank straight to the carb and the scooter ran the same. Since fuel hose is see through, i saw that i was getting good flow of gas no bubbles in the libe so the filter i had in place wasn't restrictive and there appear to be no blockages of fuel to limit flow. So scooter will only start if i spray lubricating oil in the intake and keep the throttle engaged. If i let go at all, the scooter dies and will not restart unless i throw in another squirt of penetrating oil spray. Problem has me real confused especially since i invested a good chunk of cash on the top end kit plus in valuable time to carefully install it
	0

09-15-2017, 08:58 AM	#8
Roscoe Join Date: Nov 2016 Location: N. of Texas and S. of Kansas Posts: 252	sounds like a vacuum leak and/or a bad carburetor. Might want to also check the valve clearance again and make sure the camshaft timing is spot on. Simplified the carburetor has four modes...cold start, idle, mid-range and power. I'd be checking the cold start enrichment and idle speed/fuel mixture adj. If that doesn't get it running right try cleaning the carb and if that doesn't work ... new carburetors are cheap for GY6s.
	0

03-06-2018, 10:06 PM	#10
Jesush91 Join Date: Aug 2017 Posts: 9	One thing is for sure. When I get projects, I like to finish them. I refuse to junk this gy6 scooter. I want to make it run right because I need to learn and be able to move on and get this scooter scooting on out the door.
	0

03-07-2018, 02:25 PM	#11
Jesush91 Join Date: Aug 2017 Posts: 9	Ok, so to get the crank from moving from the T mark, i jammed a flathead screwdriver between the nub on the flywheel case and the flywheel to keep flywheel from moving with the nub pointing RIGHT at the T line on the flywheel. After that I decided to remove the chain off the camshaft gear and reposition it after getting the cam gear to be pointing in the right middle and the 2 smaller ones line up with the head. Tried starting up the scooter using the starter, no luck. Tried spraying wd-40 in intake manifold, nothing. New top end so compression is there. Spark is strong. Fuelis there. No firing though at all now. This has me puzzled.
	0