Carb Troubles

[Anonymous]

I dipped my carbs awhile back and my bike has run great since until recently. I thought it was a coil problem but ruled that out. One cylinder isn't getting fuel, so I checked to see if there was gas in the bowl come to find out there was none. The other bowl had gas. So I pulled the carbs off took apart the one that wasn't getting fuel and dipped it again, reasembled it and installed the carbs. This time it had fuel and the other bowl didn't so I pulled them off again and dipped the other one. Installed the carbs and the other bowl didn't have gas. So after that I pulled apart the petcock and cleaned it same issue one bowl gets gas the other doesn't. If you sit there and bounce the bike both carbs will get fuel but not for long...its a shooting match to see which one will have fuel. I have checked compression and both cylinders have good compression and are with in 1psi of each other. The carbs are the ones that are preset at the factory and no adjustments can be made, other than idle and replacing jets (unless you drill out the plugs). To even get the bike to run I have to have the choke on, and hold the throttle open a bit (if I give it to much throttle it will die). The way I find out which cylinder isn't getting fuel is to pull the plug wire if it stay running with it pulled then thats the one.

Sorry about the length just wanted to be as detailed as possible.

P.S.-I ran a small wire through the jets to make sure they were not clogged.

[Scud]

Could be a couple of things...first, does the tank have rust in it?, if it does it could be clogging the needle valve on either carb or both then when you jostle it it frees it up and allows gas to fill the bowls. Second, your carbs are CV type and under that cap is a needle that adjusts the mixture, it has a rubber gasket that more then likely has been eaten away by your carb dip.

You can drill out the cap...BE CAREFUL... the cap is made of thin aluminum and if you go to deep you will hit the brass head of the needle screw and 'screw' it up. Use a small diameter drill and just barely make a hole, insert a sheet metal screw...just barely ..and use a pair of pliers and remove it (it may loosen and come out while you are drilling), then count the number of turns IN on the screw (do not seat to tightly you may break off the needle...very bad..)and make a note of how many turns so you can adjust them back to that setting when you are done dipping again, if you go that route. Order o-rings from Robert Barr and replace all o-rings in both carbs.

Try that and let us all know the verdict.

Scud

[earlfor]

Re: Carb Troubles

There is nothing wrong with your carbs. As you said, first one float bowl has gas, then it doesnt, then the other has gas and then doesnt. The float needle assembly is sticking. This is what is shutting off the fuel to the float bowl. You shake the carb rack, or shake the bike and the bowls fill. All you need to do is clean the float needle and valve and check/reset the float heights.

Earl


[quote="jayrbaker"]
I dipped my carbs awhile back and my bike has run great since until recently. I thought it was a coil problem but ruled that out. One cylinder isn't getting fuel, so I checked to see if there was gas in the bowl come to find out there was none. The other bowl had gas. So I pulled the carbs off took apart the one that wasn't getting fuel and dipped it again, reasembled it and installed the carbs. This time it had fuel and the other bowl didn't so I pulled them off again and

[SqDancerLynn1]

You need to remove the needle & float assembly The needle seat has a filter that snaps onto it IT may be cloged

[Anonymous]

Could be a couple of things...first, does the tank have rust in it?, if it does it could be clogging the needle valve on either carb or both then when you jostle it it frees it up and allows gas to fill the bowls. Second, your carbs are CV type and under that cap is a needle that adjusts the mixture, it has a rubber gasket that more then likely has been eaten away by your carb dip.

You can drill out the cap...BE CAREFUL... the cap is made of thin aluminum and if you go to deep you will hit the brass head of the needle screw and 'screw' it up. Use a small diameter drill and just barely make a hole, insert a sheet metal screw...just barely ..and use a pair of pliers and remove it (it may loosen and come out while you are drilling), then count the number of turns IN on the screw (do not seat to tightly you may break off the needle...very bad..)and make a note of how many turns so you can adjust them back to that setting when you are done dipping again, if you go that route. Order o-rings from Robert Barr and replace all o-rings in both carbs.

Try that and let us all know the verdict.

Scud

The gas tank doesn't have any rust in it, the o-rings are fine I replaced them the 1st time I dipped the carbs and when I dipped them again, I replaced all rubber parts after each dip.

I was running a good high dollar in-line fuel filter. It was bought at a Yamaha shop in a town in New Mexico, we kept having carb problems while riding ATV's there and the guy at the shop said alot of the gas stations around here have crud in their tanks and it loves to clog carbs. So we bought a few of these nice filters. I haven't had a problem running with it installed, but just to make sure I pulled the filter and ran just straight gas line and still the same problem. The screen that goes up into the gas tank on the petcock is clear.

The screens on the float valves are clean & clear, the float needles & seats are less than 3 months old. I will clean the float needles again and set the float level and see what happens.

Could it be that the bowl will fill at 1st then after the bowl is run dry the float hangs and when I bounce the bike it will become free until it empties again? Its kind of far fetched b/c the floats move very freely, you can take the carbs and tilt them and hear the floats moving. Both floats are new, I replaced them a few months ago b/c one had a hole in it, so I replaced both.

[earlfor]

Which float bowls are the problem. It occurs to me that since the fuel supplu Tee connects between the 2 and 3 carbs and the 1 and 4 are supplied off of the 2 and 3, you may have a plugged fuel tank vent. Its possible that would stop fuel from flowing before all four bowls could fill. Have you tried draining all four float bowls, then taking off the gas cap and turning the petcock to prime for about 20 seconds, setting the petcock back to run and then checking fuel level in the bowls?

Earl

Could it be that the bowl will fill at 1st then after the bowl is run dry the float hangs and when I bounce the bike it will become free until it empties again? Its kind of far fetched b/c the floats move very freely, you can take the carbs and tilt them and hear the floats moving. Both floats are new, I replaced them a few months ago b/c one had a hole in it, so I replaced both.

[Anonymous]

It is just a 2cylinder bike. It just has one tee and two carbs. As to which bowl it is it varies each time. The tee and fuel supply passages to each carb are clean.The petcock only has 2 settings run and reserve it doesn't matter which setting I have it on b/c it does it in both positons.

[Anonymous]

Arggggh! Still not working right after 5 days of screwing with it.

[Jeff Tate]

Assuming the floats were set correctly, can you drain some fuel into a clear clean jar to see if your gas has crud in it?