Carb Sync/Aux Tank

[sr73087]

I just purchased a carb sync tool from motion pro and will be syncing the carbs later this week. My first question is what vacuum port do I use? 2nd question, is it worth purchasing an auxiliary fuel tank for this procedure?

[92xjunker]

Year of the bike would help some. There are 4 ports you need to connect to. You can make a temp tank from any fuel safe container, even the fuel tank can be used if possitioned on a stand next to the bike.

[shpielers]

Aux tank might make it easier, but I've gotten along fine without ever using one.

Each of the tubes coming off the sync tool needs to be hooked up to a sync port.
For calibrating the tool, you're supposed to use the port on the carb that controls idle. In this case, that's where the idle set screw goes to, which = carb #3. I don't honestly know if that matters a lot or not. It's easy enough to get to #3 so I've just always done it like the instructions said.

[sr73087]

Year of the bike would help some. There are 4 ports you need to connect to. You can make a temp tank from any fuel safe container, even the fuel tank can be used if possitioned on a stand next to the bike.

1999 GSX750F

Aux tank might make it easier, but I've gotten along fine without ever using one.

Each of the tubes coming off the sync tool needs to be hooked up to a sync port.
For calibrating the tool, you're supposed to use the port on the carb that controls idle. In this case, that's where the idle set screw goes to, which = carb #3. I don't honestly know if that matters a lot or not. It's easy enough to get to #3 so I've just always done it like the instructions said.

I was just worried that the ports I would be using are the capped vac ports at the top of the carbs and 1 of those is being used to open the diaphragm in the fuel petcock. Are sync ports in a different spot?

[92xjunker]

http://katriders.com/vb/showthread.php?t=106237

[sr73087]

Thanks 92. But I am not sure what they mean that it is not the same as the petcock vac port. Does #4 carb have an additional port?

[shpielers]

Not on a Post kat, use the petcock vac. Line.

[92xjunker]

+1

[sr73087]

How do you keep the petcock open to feed fuel without the vac hooked up to the tank? Vacuum tee?

That is why I was saying possibly the auxiliary tank.

[92xjunker]

Aux tank

[arsenic]

Put the petcock on prime, done.

[sr73087]

So technically you can run on prime since the needle should only allow more fuel into the bowl if the float level drops correct? So what is the point in having it be vacuum operated?


Thanks again guys. Super responsive, I really appreciate the help.

[92xjunker]

Prime is to fill the bowls but, it can be used to run the bike. The vac line is used to shut the fuel off when not in use. This prevents the crankcase from filling with fuel when the float needles go bad and the engine is not running or you have an incident.

[arsenic]

Let me make this as simple as possible without a technical description. When the petcock is in "ON" or "RES", fuel only flows when vacuum is present. Meaning the engine needs to be running and the vacuum hose needs to be installed for fuel to flow. On "PRI", fuel just flows. As long as your floats heights are properly adjusted and the float needles are working correctly, they still regulate the amount of fuel coming in. If your float mechanism is not working correctly, you just created a lot more work for yourself.