Pressure Test Carb Bank

[rugguy]

Had trouble cranking after sitting for six weeks. Tore it down and took carbs apart and cleaned. Reassembled and she started and ran like a champ on the first try.

Problem: Major fuel leaks (is there any other kind?) from both sides of carb bank under 1 & 2 carb. Suspect bowl gasket problems. Will tear down again this week. Ordered new gaskets.

Question? Is there a way to perform a positive pressure test on the carb bank on the bench? I sure would like to find any and all leaks BEFORE I put her back together.

Thanks...ready to ride.

[signart]

Check for fuel rail "O" ring leaks.

[rugguy]

Thanks signart....I ordered the fuel rail "o" rings a few minutes ago from redeye.

[Challenger]

I set the tank on a chair and ran a fuel line to the carb bank siting on the floor, pulled vac on the petcock with a vac gun and let it set for an hour. Found a fuel rail o-ring leaking.

[rugguy]

Ok Challenger, thanks for the info. I have done a lot on engines but never this. I want to make sure I do it right.

I will:
set the tank higher than the carb bank
connect the fuel line to the "t" and the lines that supply the fuel rail

So do I put the vacuum between the petcock on the tank and the fuel line?

[Attic Rat]

To check the float bowls for leaks you take a clear piece of thick plastic and place it over the float bowl. You then open up the drain screw and pull a vacuum on the float bowl. If it holds vacuum the gasket is good if it doesn't the gasket needs to be replaced. If you order the float bowl gaskets from Rich (Red Eye ) he will supply the plastic piece.

[rugguy]

Thanks Attic Rat...I ordered them from him today. The gaskets are all getting replaced regardless. I am concerned about leaking at the fuel line "t's" on the fuel rail. Ordered that set from him too. But was hoping to be able to "bench test" the whole system before I put it back in. Leaking air is one thing...leaking fuel is another. Especially with 7 gallons in the I/S tank right between my legs.

[Bighead]

You got a special tank?

[rugguy]

Oops....I shouldn't have said over 7 gallons. But 6.87 with the reserve is close enough to 7 for me.

[Bighead]

Changed your post? You said over 7 gallons. I was just curious because I wanted one without having to put a belly tank on.

[rugguy]

I did change it....I got ahead of myself there with the "over 7 gallons" part. But I'm sure you'd agree, regardless of how much fuel your tank holds, you don't want it igniting while you're riding. Our any other time for that matter.

[Bighead]

No doubt but would rather it flame up with a full tank than 3/4 empty BLOOOOOOOOIE! It would go.

[rugguy]

Gonna break something!!!

Today, I fired up the beast just to make sure it would start. Cranked like a champ and mysteriously the fuel leaks have temporarily disappeared (I read a thread about cold weather leaks disappearing). But, I am still changing out all of the gaskets as soon as they arrive.

But like any normal man, being as the specter of a fiery death was reduced, and it was clear and 70, and the bike was running, I took it for a spin around the n'hood. After 30 seconds it began to miss slightly and run a little rough. After a minute the whole thing was bogging down and growling. Stopped, waited as long as a man will wait for anything, a whole 30 seconds and fired it back up. Still running like garbage. Limped back to the garage.

Brief history. 22k. Took it to Colorado where it sat for six weeks without running. Would not crank. Came back, tore down the carbs and cleaned everything. Cranked Saturday night after reassembly and ran great but fuel leaking from front of both sides of carb banks (1&2 carbs). Parked, ordered all new gaskets, then today came.....

Carbs cleaned
Fresh fuel w Seafoam (not too much)
Oil and filter change
New coolant
Fuel petcock "on"
Choke fully "off" (checked choke linkage position to verify)
No vents hoses kinked (that I can see)
Hot spark to all new plugs

Any ideas? Other than hire a real mechanic?

[Thunderbolt]

Clean everything up again when you get all your pieces n parts.  Crud gets in the lines over time and when you put it all back together it will get dislodged and clog the slow jets again.  Had it happen to me.  The ethanol does a good job of cleaning the tank and lines and depositing it in all the smaller orifices.  Seafoam or Techron will help, but since you are taking it apart again anyway.....  Before you fill the tank next time do as suggested and locate the tank where you can check for leaks, but leave all the drains open and let some fuel run out of all the carbs before you close them to do the leak check.  That will help to further flush the lines.

[Thunderbolt]

Also you might have kinked the vent line as the reason for the crappy running on your checkout cruise.  You know the one on the rear of the tank.  I usually pull on the bottom of the line as I seat the rear of the tank.

[rugguy]

Reassembled and no leaks...thanks to redeye and his carb and fuel rail gaskets. Now I am chasing a skip that you can really hear at idle. When you get on the throttle it seems to disappear but that could be the other five cylinders making up for it. I am going to run a couple of tanks of fresh gas with Seafoam through her before I tear her back down. Hoping it's just some gunk that is clogging up a slow jet. If a couple of tanks doesn't fix it I am going to re-jet the whole thing.