Wildguzzi.com
General Category => General Discussion => Topic started by: brider on August 07, 2025, 06:02:11 PM
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My '07 has been exhibiting a fuel-leak phenomenon for 6 mo or so, really this entire riding season.
If I start it cold on the sidestand, raw fuel begins to drip from the base of the left cylinder (right onto the header). The drip seems more intense when the bike is running rather than with just the key on and the system pressurized. Looking as best as I can up and underneath the TBs, I can see NO obvious leak path from them, or the fuel hoses, which are basically in-line with or BEHIND the TBs.
On the centerstand, I checked today and with the key just ON and not starting the bike, sure enough the left cyl base becomes wet with fuel sheen and you can smell it, the RH cyl base remains dry. And again, I can see NO evidence @ the TB or injector connections of fuel leakage.
I took the tank and airbox off a couple of weeks ago to check the fuel connections, and all is tight and leak-evidence-free (when I did the oil pressure switch fix last year, I changed the factory heat-shrink fuel lines with EFI hose & good clamps, and added a BETTER tank dis-connect).
Since I can see no evidence of leaking @ the TBs or fuel connections, and they are behind the cylinders anyway, IS there a mechanism to leak fuel at or around the cyl base? When I had the tank off I was wishing there was a way to pressurize the system with the tank off, but couldn't think of a way to do it.
Ideas?
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My first thought was the fuel lines but if those have been proven to be dry and the clamps snug that rules that out.
Did you check if the screws holding the fuel pump to the bottom of the tank are all snug and tight (not over tightened as they go into plastic).
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The fuel tank leaks at the seams on a lot of these, they can also crack in the tunnel. Chuck in Indiana knows the specifics on why but I forgot. Edit: I was thinking of EV tanks but I’d check the tank, maybe some Norge tanks do the same
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Leaking tank or pump connections would leak all the time, wouldn't they? Not just at key "ON"? Unless I can get a better view with a light and mirror I'll probably have to pull the tank again, is there a tool available that will pressurize the system with the tank off? Seems like that should be a Harbour Freight thingy...
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I wouldn't risk a compressor, but a bicycle pump might work.
You might hear it hissing.
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If the tank itself leaked it wouldn't just be when the pump is running because the pump doesn't cause pressure in the tank, it creates pressure on the lines.
Lines or fittings might leak under pressure.
If an injector was leaking it might cause fuel to drip because of excessive fuel discharge.
That's about all I can think of which could cause a leak.
If you can't just raise and support the tank enough to use the pump to pressurize the system but still allow you to see, then you either need to fabricate jumpers for the harness and fuel line or attach a hand pressure pump to the fuel line quick-connect.
I would think a hand pressure/vacuum pump like a brake bleeding tool (Mityvac) would work easily, you just need a proper sized fitting for the quick-connect. Basically something that mimics the fitting on the fuel pump. Be careful not to exceed the fuel pump regulated operating pressure, probably something around 35-40 psi.
https://a.co/d/1CLoN5K
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Sounds like the return line to the tank could be leaking but I’m not familiar with the plumbing on a Norge.
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Sounds like the return line to the tank could be leaking
There's a return line?!? Why wouldn't the internal regulator just dump pressure straight back into the tank?
I wouldn't expect anything modern to have a return line.
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Just realized that.
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Thanks for the link to the hand pump, that's a great idea.
As I recall there is no plumbing underneath the fuel tank forward of the pump & vent lines. The line from the pump goes to a T somewhere just forward of an imaginary line between the 2 cyl intake bodies, then 2 simple lines to the injectors. You can get eyes on the injector connections, but not on the T between them. This leak is evident from the left cyl base, which is FORWARD of the T connection, so maybe there's a tiny spray from that T, under pressure, biased toward that left cyl? That's the only path I can think of.
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Based on your first statement I thought you had checked the fuel lines.
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Based on your first statement I thought you had checked the fuel lines.
Yes, I DID check the fuel lines, didn't see anything, and the hoses & clamps were practically new. But what other source IS there for a leak? Gotto go back in there and check with the system under pressure.
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Yes, I DID check the fuel lines, didn't see anything, and the hoses & clamps were practically new. But what other source IS there for a leak?
Fuel injectors and injector seals.
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Yes, I DID check the fuel lines, didn't see anything, and the hoses & clamps were practically new. But what other source IS there for a leak? Gotto go back in there and check with the system under pressure.
You can lift the tank and put an 8 inch block of 2x4 wood to prop it up just enough so you can see underneath w/o having to disconnect the fuel line to the L shaped nozzle on the bottom of the tank.
I would do that and then turn on the ignition and see if you see any fuel moving under the tank, it will give you good enough visibility above...but to really see the lines below will require taking the airbox out.
I suppose you could puff some talcum powder in there and see where it gets wet first...
Given that it is on the left side while on the side stand, maybe try keeping it on the center stand (I think you did this already) when you lift the tank to keep it level at least and see where the fuel is travelling from.
Presumably your 2 vent lines are all tucked well below the frame and were not "pinched" under the tank or folded in by accident.
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Fuel injectors and injector seals.
That's my thought.
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The fuel injectors are what the fuel line clamps to, right (I'm not afraid to ask a dumb question...)? I assume they can be removed easily, and it's a o-ring seal? Do these things leak on occasion like any other seal interface? Guess I never saw a post about something like that, but then this is my first FI bike.
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The fuel injectors are what the fuel line clamps to, right (I'm not afraid to ask a dumb question...)? I assume they can be removed easily, and it's a o-ring seal? Do these things leak on occasion like any other seal interface? Guess I never saw a post about something like that, but then this is my first FI bike.
Without looking up particulars on the CARC bikes, fuel injectors normally mount directly to the throttle body or intake manifold and are held in place sandwiched by a bolted-on fuel rail/pipe.
The injectors are sealed at both ends by seals/O-rings which are generally replaced if the injectors are removed or disturbed.
The fuel lines normally clamp to the rails/pipes.
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Well Lo & Behold, the leak WAS/IS at the T-fitting in the fuel lines. I looked from the RIGHT-side this time with a flashlight, and got a clear line-'o sight to the fitting by sticking a long screwdriver in and pushing a big harness out of the way, and saw the fitting positioned right over the base of the left cyl. Began weeping as soon as I turned on the key.
Good thing is I'm getting good at removing the tank & airbox! Best thing I ever did was install a quick-disconnect fitting in the fuel line from the tank so I don't have to fumble around with the factory disconnect.
Cause of problem: The barbed T-fitting I used was either the original or different (can't remember) but it was UNDERSIZED for the hoses, the clamps could not clamp hard enough against the thick OD of the hose.
Thanks for chiming in, all!
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Good find.
What did you use for quick disconnect?
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What did you use for quick disconnect?
I found a link in a discussion on that very subject in these pages, when I first tried to disconnect the factory dis-connect. Couldn't do it and considered it another in a long line of mystifying Guzzi design details. So I installed my own, downstream of the original. I'll dig for a post and re-post it. No tools req'd.
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Here’s the disconnect kit recommended years ago here in the site. I have one but never installed it…one of these days! Getting the green fuel line pliers does the disconnect very easily so this piece of jewelry remains unused so far.
https://www.beemerboneyard.com/cpcqkdiscon.html
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Thank you both.
Yeah, the QDs approach jewelry prices.
I've seen the pliers post here. I'll dig it out.
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I found a link in a discussion on that very subject in these pages, when I first tried to disconnect the factory dis-connect. Couldn't do it and considered it another in a long line of mystifying Guzzi design details. So I installed my own, downstream of the original. I'll dig for a post and re-post it. No tools req'd.
Funny, I've never had a problem with them. Glad I didn't know they were a problem or I would have psyched myself out. Usually a first time go, though you have to have the angle and hand position spot on.
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It seems the US market mostly uses fuel connectors with an outer release ring. Plenty of pliers online to release these connectors.
This frontal release type connector used on the Norge seems more common in Europe and needs different pliers.
There are cheap versions that I tried to buy (try searching for FUEL LINE DISCONNECT PLIERS) and twice got the order cancelled after placing it. I don't know what's going on, so I went for a more specialized seller.
I found these in the US and at a reasonable price: https://www.apexinds.com/tools/TE4406.html?srsltid=AfmBOopzNy1Zm21VUMKmo_IaheWm3axHFoLM7vikV3uiZ4gGjmvZtCvV (https://www.apexinds.com/tools/TE4406.html?srsltid=AfmBOopzNy1Zm21VUMKmo_IaheWm3axHFoLM7vikV3uiZ4gGjmvZtCvV)
The pliers are green as mentioned in other posts: https://wildguzzi.com/forum/index.php?topic=75387.msg1438172#msg1438172 (https://wildguzzi.com/forum/index.php?topic=75387.msg1438172#msg1438172)
I don't know if they are the correct size. I might give them a try when I get my bike allowance.
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Yes, the beemerboneyard disconnect is the one I bought, but thru ebay and I'm positive I didn't pay more than $30 for it. I had more angst researching what type of pliers and how to use them. Now I don't need any tools.
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Pescatore, those look like the ones in a cheap HF kit. I tried the pliers on my EVT, they didn't seem to help, though they seem to for some. The biggest help is depressurizing the fuel system before trying to remove the QD. Also something like WD40 sprayed in the end where the QD ends join seems to help.
Tom
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It seems the US market mostly uses fuel connectors with an outer release ring. Plenty of pliers online to release these connectors.
This frontal release type connector used on the Norge seems more common in Europe and needs different pliers.
There are cheap versions that I tried to buy (try searching for FUEL LINE DISCONNECT PLIERS) and twice got the order cancelled after placing it. I don't know what's going on, so I went for a more specialized seller.
I found these in the US and at a reasonable price: https://www.apexinds.com/tools/TE4406.html?srsltid=AfmBOopzNy1Zm21VUMKmo_IaheWm3axHFoLM7vikV3uiZ4gGjmvZtCvV (https://www.apexinds.com/tools/TE4406.html?srsltid=AfmBOopzNy1Zm21VUMKmo_IaheWm3axHFoLM7vikV3uiZ4gGjmvZtCvV)
The pliers are green as mentioned in other posts: https://wildguzzi.com/forum/index.php?topic=75387.msg1438172#msg1438172 (https://wildguzzi.com/forum/index.php?topic=75387.msg1438172#msg1438172)
I don't know if they are the correct size. I might give them a try when I get my bike allowance.
Those are the correct green ones - makes very easy work of disconnecting the line - no forcing required just a little gentle wiggling.
I have not had to de-pressurize to make them work, but what I do is drain the tank first with a siphon into a 5 gallon gas can...and then very little dribbles out once the line is disconnected from the elbow under the tank.