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Post by mgreenfield on Jul 17, 2006 21:29:03 GMT -5
Friends, ...I'm pleased to be here, and understand this is a great forum for scoot topics. Here's mine.
I recently bought a Roketa Jamaica-150 "in the box" from countyimports.com.
It was very!!! difficult to get started from a dry tank, and I think this was because of the vacuum operated fuel valve and long tubing to/from this valve. I got in running (finally), but last time I ran the scoot, it would die after riding a few minutes.
This happened several times, and each time I pulled the fuel line off the carburetor, ....bone dry. It's as if the fuel valve is shutting off again after a while eventhough the engine is running.
Any thoughts on this???
ALSO, I note that the line delivering fuel to the carburetor has a 'T' in it, and there is a line from this 'T' to the intake manifold ahead of the throttle plate. What's this line for. Surely it's not to just dump raw gas into the carb.
Many thanks, and I look forward to participating with you-all on this forum!!
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Post by bob on Jul 17, 2006 21:42:51 GMT -5
It sounds like you are pulling the vacuum line off. The fuel valve should have 3 hoses going to it. One from the gas tank, one to the fuel filter(make sure it is pointing the correct way) then to just above the bowl on the carb. These two should be 180 degrees apart. The third hose should be at 90 degrees and go to the "T" then the manifold and the carb. At least thats the way it is on my Bandit. You can look at www.oregonvintage.comBob |
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Post by 90GTVert on Jul 17, 2006 21:44:04 GMT -5
Nope, you've got it mixed up a bit. There is a vacuum line from the intake to a "T", then from the "T" one goes to the right side of the carb (Vacuum for the CV carb) and the other side goes to the fuel pump to open the shutoff and operate the pump. There is a fuel line from the tank to the pump and from the pump to the carb, which is connected on the left side of the carb. These pumps are not very efficient when you have a low fuel level or any sort of vacuum leak. I'd replace all fuell and vacuum lines as well as the filter and spark plug, first thing. Chinese rubber products are not very good and it will save you some grief down the road. Personally, I remove the pumps and replace them with electric pumps and I have no delivery problems at all. Stan Friends, ...I'm pleased to be here, and understand this is a great forum for scoot topics. Here's mine. I recently bought a Roketa Jamaica-150 "in the box" from countyimports.com. It was very!!! difficult to get started from a dry tank, and I think this was because of the vacuum operated fuel valve and long tubing to/from this valve. I got in running (finally), but last time I ran the scoot, it would die after riding a few minutes. This happened several times, and each time I pulled the fuel line off the carburetor, ....bone dry. It's as if the fuel valve is shutting off again after a while eventhough the engine is running. Any thoughts on this??? ALSO, I note that the line delivering fuel to the carburetor has a 'T' in it, and there is a line from this 'T' to the intake manifold ahead of the throttle plate. What's this line for. Surely it's not to just dump raw gas into the carb. Many thanks, and I look forward to participating with you-all on this forum!! |
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Post by ryan_ott on Jul 17, 2006 21:44:38 GMT -5
that t is for the vaccum line, make sure they are connected
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Post by Twigster on Jul 18, 2006 10:10:52 GMT -5
I had the same problem. I've bypassed my fuel Vacuum petcock & ran a straight "gravity feed" line with the fuel filter directly to the carb. Works great! No more fuel starvation. Still thinking of adding a electric fuel pump in the near future.
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Post by Jacine on Jul 18, 2006 15:04:59 GMT -5
I replaced the plastic tees with brass barbed tees from Ace hardware. From the difference in performance, I think there was probably a small vacuum leak at one of the tees. In this heat, the rubber tends to expand at a different rate than the plastic, and the connections are not tight enough.
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Post by subarutech on Jul 18, 2006 19:56:11 GMT -5
hello mgreenfield,i also have the same scooter with the same problems at first.it is in your best intrest to take out the under seat storage tray,seat and cross bar to the seat mount,remove fuel tank to gain access to fuel lines and carburator.what i found on my scooter was the vent hose for cylinder head to air cleaner box twisted and collapsed.vent hose for tank left off and tank vent tube capped off.fuel line from tank to carb pinched on side of tank.i finally decided to remove the vacuum hose and cap them off and am now using a electric fuel pump.best thing i have done yet.heres a link. scootdawg.proboards59.com/index.cgi?board=tipsandtricks&action=display&thread=1152021224 |
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Post by 90GTVert on Jul 18, 2006 23:35:00 GMT -5
Did you have a gravity feed system with a vacuum shut off, or one of the actual pumps? I'm curious about this because I was wondering if the pump was even needed on the under seat tank systems. I love the electric pumps on the Touring models, but on those, the tank is below the carb so you have to have some sort of pump. Stan hello mgreenfield,i also have the same scooter with the same problems at first.it is in your best intrest to take out the under seat storage tray,seat and cross bar to the seat mount,remove fuel tank to gain access to fuel lines and carburator.what i found on my scooter was the vent hose for cylinder head to air cleaner box twisted and collapsed.vent hose for tank left off and tank vent tube capped off.fuel line from tank to carb pinched on side of tank.i finally decided to remove the vacuum hose and cap them off and am now using a electric fuel pump.best thing i have done yet.heres a link. scootdawg.proboards59.com/index.cgi?board=tipsandtricks&action=display&thread=1152021224 |
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Post by mgreenfield on Jul 19, 2006 7:57:43 GMT -5
Friends, ....many thanks for your responses.
1/ First chance I get, I'll redo all the tubing to put quality rubber in there on tight fittings.
2/ The fuel supply is gravity feed from the tank to a little vacuum diaphragm operated shut-off valve. From there fuel goes to the carburetor. Again, it's all gravity feed. I can pull the vacuum line off the intake manifold, suck on it, hear the valve "pop" open, and get fuel flow without the engine running. Nice to know this if I ever run the tank dry. I could pipe direct from the bottom of the tank to the carb, but then I'd depend on the carburetor float valve to shut off all fuel flow, and that's not very reliable. Would hate to open the garage door some morning and find a gallon of gas on the floor.
3/ I removed the gas tank, AND the heat shield under the gas tank to get to the crankcase vent tube, which was crimped closed, AND which caused the oil to squirt out the filler when I tried to check oil level with a hot engine. I checked other tubing for crimps then.
4/ Couple of you were right. I did have a tube or two mis-identified. Here's the engine compartment tubing "shopping list" as I see it now. One vacuum tube from intake manifold to exhaust emissions control air valve. One vacuum tube from intake manifold to 'T'. Leads from 'T' to carb CV diaphragm chamber, and to fuel valve. Finally, one tube from carb float bowl to fuel valve. This is the only one with fuel in it.
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Post by Jacine on Jul 19, 2006 8:44:49 GMT -5
If you can color code the tubing. Vaccuum line, small cooling line and fuel lines of different colors make it easier to work on.
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Post by subarutech on Jul 19, 2006 18:03:53 GMT -5
Did you have a gravity feed system with a vacuum shut off, or one of the actual pumps? I'm curious about this because I was wondering if the pump was even needed on the under seat tank systems. I love the electric pumps on the Touring models, but on those, the tank is below the carb so you have to have some sort of pump. Stan gravity feed system with a vacuum shut off.tank above carb obviously with this set up.just bought my wife a roketa bali 150 and will put electric pump on that also.just like the fact of having a constant fuel supply.dont have to rely on vacuum set up |
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Post by mgreenfield on Jul 20, 2006 10:11:48 GMT -5
Fuel tank is under the seat with gravity feed to the vacuum-operated fuel off/on valve. From the valve it continues via gravity feed to the carburetor. No pump.
I have a Suzuki Burgman400 with the fuel tank low under the center hump. This has an in-tank electric fuel pump. When you turn on the ignition, you can hear it whir for a few seconds as it pressurizes the fuel injection system. This is an entirely different animal.
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