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eARRROOOOOGA
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Discussion Starter · #21 ·
Well... All vents are clear.

This vents from the top of the tank at the filler neck.

Odd thing is that it has a stopper on the end of it. It's clipped in place with the clamps like are on the rest of the hoses, so I think it came from the factory that way.

Not sure what this is for:


The funnel looking thing has a hose that joins & follows the rest of the drain/vent hoses. Nothing really lines up with it other than it's near the very rear-most portion of the tank.

I did put a small amount of air pressure on the fuel like and it pushed fuel out around the bowl gasket on one of the carbs. I'm guessing that's the source of the leak.

JM
 

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eChuckB
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7,122 Posts
Forrest, at the top of the tank, where the cap seats, is there one or two small holes? Maybe one that mates to a nipple on the bottom of the cap and one that doesn't ?
 

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eARRROOOOOGA
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17,313 Posts
Discussion Starter · #23 ·
I only saw one hole around the filler cap DrD. Using my air compressor, I found that it connects to the nipple on the bottom of the tank I showed in the pic.

JM
 

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eChuckB
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7,122 Posts
Forrest,

There should be two holes. The smaller one is the vent, the larger the drain. They are located almost 180 degrees apart from one another. The venting for the tank is controlled by a small valve in the cap, which could be clogged.

Naturally, you'll want to be sure both are clear.
 

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eARRROOOOOGA
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17,313 Posts
Discussion Starter · #25 ·
I'll take another look, this was a quick, freezing temp glance with a flashlight. I'll try again :lol and report back my findings ~

JM
 

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eChuckB
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7,122 Posts
No worries...the vent line should mate with the valve on the cap. I know how it can be working in a cold garage. This will be my first full season with heat.....and I am loving it :D
 

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eARRROOOOOGA
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17,313 Posts
Discussion Starter · #27 ·
Around the lip of the filler opening, there is just the one hole that connects to the nipple on the bottom of the tank. There is a hole in the filler cap that is likely a vent. However, I'm not sure where it vents unless it simply vents into the air above ~

JM
 

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eChuckB
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7,122 Posts
Hmm, well, I was not trying to put too fine a point on it but whether or not the pressure building in the tank is the cause of your leak, it seems advisable to be sure your tank is venting properly.

I'd had a quick text chat with a friend that was a Honda tech for years and he is certain the tank has both drain and vent provisions.

He also reminded me that it is now cold and snowy so I should start bolting the 400F motor back together. :D
 

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eARRROOOOOGA
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17,313 Posts
Discussion Starter · #29 ·
I'll put a small amount of air pressure (just a couple PSI) on the hole in the filler cap and see what happens/where the air goes. That'll help me locate where it vents too AND if that vent is proper. I'm thinking the two are related because when I put a tiny bit of air in the fuel line, it seeped gas. Either way, I may still be replacing a bolwl gasket on one of the carbs. From the looks outside of the carb bowl, this isn't the first time it's leaked.

JM
 

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eARRROOOOOGA
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Discussion Starter · #30 ·
UPDATE: Now that I garage no longer feels like it's located in Antarctica, I got back to work on the Hawk.

I pulled the carbs off, opened them up to find very dirty carbs. Lots of gunk stuck to the float bowls, lots of trash in them too. Got them cleaned up and reassembled.

In removing the carbs, I found the clamps were loose on the forward cylinder intake boot. That explains the idle moving around a bit. Reassembly fixed that problem.

In the meantime, I put a little air pressure on the vent built into to fuel cap and it seemed like it was clogged a bit at first, but it cleared up after a few puffs of air.

I reassembled everything and finally got fuel back into the carbs got it to start. New problem. It wouldn't idle. Seems like the leaky intake boot had caused it to idle too high and rather the fix the real problem, they just turned the idle down. Simple enough fix of readjusting the idle had it running fine.

So, after all of that. It's back together.

1. It idles properly and doesn't "hunt" idle anymore
2. Fuel no longer leaks from the rear-cylinder carb
3. The hesitation when opening the throttle after a closed-throttle deceleration is gone
4. Maintaining a steady speed no longer induces a random stutter from the motor

The only issue that is still present is the fact it feels anemic once you get into the upper third of the revs. It's got lots of power down low though. I have two theories:

A) Since it's motor was bred from the VT500 cruiser, it's just the way the motor acts. It has power delivery similar to a cruiser, and I'm just used to how the Ducs rev out and it's not really an issue, but normal behavior.

B) I discovered that along with the full Supertrapp exhaust system, it also has a K&N filter. It's very possible one of the previous owners tossed the filter in and put the exhaust on and didn't bother to rejet. I'm going to see if I can find what size jets it originally had and check the numbers on it's main jets next time I have it down for service. Since it runs great down low and has crisp throttle response, I'll likely just go up a size or two on the main and leave everything else alone and see what happens.

Thanks for all the input folks!

JM
 
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