Working on a friends 81 yamaha 650xs. I removed and cleaned the carbs and put them back on but can t remember how the T hose from the petcock to the carbs hook up. Can someone help me

i dont think you need a new carb but if you are already getting one this is fine you need to find out what jets are in it or you can get jet kits for your carb and change them yourself they come with instructions. with it running for a while just fine and then dies this sounds like you may have water in the gas or dirt in the carb bowl to check for dirt get a clean empty water botter clear one put the hose from bottom of carb in bottle and open the bleeder screw on the bottom of the carb bowl if there is dirt or water you will see it in the bottle empty the bowl then turn on the gas petcock let a bit more run through shut of petcock and close the bowl screw , if you see dirt then you should clean the carb remove and rebuild while you are doing this you can install larger jetting good luck

is this the bottom of the carb? if it is then the problem is probably from the overflow. your float and needle valve are probably sticking. take the card apart and clean it well. before putting it back together, make sure the float and needle move freely.
hope this is of help

I'm guessing that the fuel block you refer to is the inner side of the petcock assembly. If this is so, the larger line is the fuel supply and connects to a swivel pipe in between two of the carburetors and feeds all four through internal piping. The second smaller hose is a vacuum line to operate the petcock and runs from one of the rubber carb mounts to the petcock. My 85' model also has four vent hoses running from the top front part of each carb back and down between each one. I hop this helps.

Your float in the bottom of the carb is likely stuck in the up position. The float attaches to a valve that shuts off fuel flow when level is just right. Can you see the little screw at the bottom of the bowl? Do you see the little overflow hose below that? Get a plastic soda bottle, put the outlet of the tiny hose into it. unscrew that little screw a few turns. Do you see fuel coming out? No? then take the back end of a screw driver and tap the bowl of your carb sharply 5 or 6 times. (Make sure the fuel pet **** under the tank is turned on. If you do not see fuel going into your bottle in a minute, shut off fuel at the tank. Screw the bowl drain back in. Remove the larger incoming fuel line that goes from tank to carb and put it into the bottle. Now you will open the petcock a little bit slowly. If you never see fuel come out of the tank, thru that hose, then your screens on the petcock may be clogged. Shut off fuel , Remove the cap on your fuel tank. blow into the line while slowly opening the petcock valve. Hear air bubbling in the tank yet? If you do, shut off valve, remove air pressure from line, point it back into the bottle and reopen the valve. If none of this works, then you need a new petcock valve.

take off the part that goes round the handle bars then take it apart and un srue the cable from the engin transformer.

ALWAYS have a fire extinguisher on hand when working on carburetors.
Remove the water trap bowl at the bottom of the petcock, (gas valve). Is there any water or trash in the bowl? Drain a cup of gas from the tank. Is there any water or trash in the cup? Dump it, clean it and re-mount it, ( not all bikes have a water trap bowl ).

Drain the carburetor. There should be a screw on the lower side of the carb float bowl. Remove the screw then replace it after the fuel drains. Turn the gas back on and wait a minute for the carb to fill with gas. Install a new stock NGK spark plug and try to start the engine. If the bike doesn't start and run properly then shut off the gas and remove the carburetor from the engine.

Remove the float bowl and clean the entire carb with a spray carb cleaner from the auto parts store. Wear protective goggles to avoid getting spray in your eyes. Spray into all the little airways and fittings in the carb. Before putting the slide back in the throat of the carb, move the clip on the jet needle one notch lower. Put the rest of the carb back together, clean the air filter and install the carb. Let the float bowl fill then start the engine. This process should get you back on the road.

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• The only way petrol can get into the crankcase is through the carbs and then into the cylinder and past the rings.
• Drain the gearbox and put in some fresh oil.
• Turn the fuel petcock to OFF.
• Drain the carbs then remove the water trap bowl from the petcock. Does some fuel still get past the petcock valve? Replace the petcock if it does. If the petcock is working properly then remount the bowl.
• From this point forward, ALWAYS shut the gas off when the bike is not running.
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