bike dies after warm up
- Thread starter xb957
- Start date
to answer your question.. no. the fuel system is gravity fed so reguardless of engine conditions, fuel should flow.
the oil around the head is a problem in its own too.
the oil around the head is a problem in its own too.
Hi a.graham,
I took the gastank off and check for a possible blockage, but didn't find any.When I take the fuel line off and open the fuel valve ,gas flows. Could the issue be in the carb? I tried bleeding it with the bleeder valve and even tried running it with the fuel cap off. What could be the problem?
I took the gastank off and check for a possible blockage, but didn't find any.When I take the fuel line off and open the fuel valve ,gas flows. Could the issue be in the carb? I tried bleeding it with the bleeder valve and even tried running it with the fuel cap off. What could be the problem?
It would help a lot if we knew what engine and carburetor you have. People usually assume it is a Chinese 2 stroke but we have no way of knowing that unless you tell us.
If we are talking Chinese engine, the "bleeder valve" you mention tells me you have the NT style carburetor. That isn't a bleeder but a primer of sorts. It simply pushes the float down allowing an over rich condition which sometimes helps on a cold start. If used, you just push t down and hold for a few seconds. It isn't a pump.
Does the engine shut down while riding or just when idling? There is a big difference. If the problem is at idle maybe all you need to do is adjust the idle speed screw in a turn or so. If the engine quits when you're riding you might have a weak ignition problem.
The CDI has been found to be a culprit when this situation shows up. They work fine until warm then start to fail. Rare but it has been reported several times.
You said you confirmed fuel flows from the tank. How steady is the stream when you check it? It must be a steady stream and not dripping or intermittent. Are you using an in-line fuel filter?
As far as the oil around the head, it could be the head bolts aren't tight enough or a bad head gasket. A leaking head gasket will often show up as oil and/or a ticking sound, especially when the engine is cold. If the studs are 8mm the nuts need to be torqued to 120 to 140 inch pounds. You might want to remove the cylinder head and inspect the head gasket. A leaking gasket is easy to see. Look for a dark area extending from the combustion chamber side to the outside diameter of the sealing surface. We also recommend that you replace the chrome acorn nuts with hex nuts. The acorns are notorious for bottoming out on the studs before applying force to the cylinder head.
Use the search feature and read about 'lapping cylinder head' for a better gasket seal.
Tom
If we are talking Chinese engine, the "bleeder valve" you mention tells me you have the NT style carburetor. That isn't a bleeder but a primer of sorts. It simply pushes the float down allowing an over rich condition which sometimes helps on a cold start. If used, you just push t down and hold for a few seconds. It isn't a pump.
Does the engine shut down while riding or just when idling? There is a big difference. If the problem is at idle maybe all you need to do is adjust the idle speed screw in a turn or so. If the engine quits when you're riding you might have a weak ignition problem.
The CDI has been found to be a culprit when this situation shows up. They work fine until warm then start to fail. Rare but it has been reported several times.
You said you confirmed fuel flows from the tank. How steady is the stream when you check it? It must be a steady stream and not dripping or intermittent. Are you using an in-line fuel filter?
As far as the oil around the head, it could be the head bolts aren't tight enough or a bad head gasket. A leaking head gasket will often show up as oil and/or a ticking sound, especially when the engine is cold. If the studs are 8mm the nuts need to be torqued to 120 to 140 inch pounds. You might want to remove the cylinder head and inspect the head gasket. A leaking gasket is easy to see. Look for a dark area extending from the combustion chamber side to the outside diameter of the sealing surface. We also recommend that you replace the chrome acorn nuts with hex nuts. The acorns are notorious for bottoming out on the studs before applying force to the cylinder head.
Use the search feature and read about 'lapping cylinder head' for a better gasket seal.
Tom
It sounds like the tank cap is not venting, loosen the cap and try it. Don't do this with a full tank or fuel could spill on you. Sometimes people have had to drill a small vent hole in the cap.
Hey everyone,
Thanx for all the great advice. I found two problems; one, found a small chunk of teflon tape in the carb jet (who knows how it made it through the filter and two, the CDI on the boot side I suspect was loose. It's not the screw type connection but the spring type which is sqeezed into the wire. Either way it is running again so thanks once again. I am going to invest in a better CDI and carburetor.
Thanx for all the great advice. I found two problems; one, found a small chunk of teflon tape in the carb jet (who knows how it made it through the filter and two, the CDI on the boot side I suspect was loose. It's not the screw type connection but the spring type which is sqeezed into the wire. Either way it is running again so thanks once again. I am going to invest in a better CDI and carburetor.
Glad you're up and running but I hate to see you waste money. You have the best carburetor for a stock engine and the factory CDI will give you everything you can expect from that engine. The weak link is the spark plug boot. Get rid of it and replace it with a good automotive quality boot. That will require that the spark plug retain the top cap. There are spark plug alternatives to the kit plug such as the popular NGK B6.Hey everyone,
Thanx for all the great advice. I found two problems; one, found a small chunk of teflon tape in the carb jet (who knows how it made it through the filter and two, the CDI on the boot side I suspect was loose. It's not the screw type connection but the spring type which is sqeezed into the wire. Either way it is running again so thanks once again. I am going to invest in a better CDI and carburetor.
Use an in-line fuel filter. Clean fuel is all the NT carb requires. Once you do those things I think you'll be happy with your engine. Keep us informed and ask if you have further problems.
Tom
