Author Topic: Breva 750 leaking gas from left side  (Read 349 times)

Offline MotoGuzzi750

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Breva 750 leaking gas from left side
« on: December 05, 2021, 09:32:25 PM »
Hi experts,

Yesterday after parking 2004 Breva 750 IE after ride, I noticed drops of gas leaking from left side on the top of left exhaust ( drops of gas falling on on exhaust pipe near the side stand ). It does not leak when the engine is shut off.
It leaks when the engine is running.
I can smell gas as drops fall from above on hot exhaust pipe. Also i can clearly see drops as they fall.
The drops stop falling few mins after engine is shut off. If I ignore the leak, bike is driving normal.

1. What could be causing this and how do I repair this leak ?

Appreciate any tips/hints/guidance.

Thanks in advance.

Offline Muzz

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Re: Breva 750 leaking gas from left side
« Reply #1 on: December 05, 2021, 10:07:56 PM »
I have a 2003 Breva.  Must say I have never had the problem  I must also say I have never had the tank off either (air cleaner service awkward but doable :rolleyes:).

I suspect that you have a leaking either fuel line or union on the motor side of the pump, which is why it only leaks while the bike is running.

I have never had the tank off because those who know say that the "quick release" fittings can be an absolute bear to undo.  Let the fuel line depressurize before you attempt to undo them.

Be also aware that if you have been using fuel with ethanol in it you may find the tank bolt does not line up with hole.
Muzz. Cristchurch, New Zealand
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Offline malik

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Re: Breva 750 leaking gas from left side
« Reply #2 on: December 06, 2021, 03:53:12 AM »
Best to take the tank off & have a look. (It's easy enough to learn how to disconnect the QD (quick disconnect), just follow the instructions that abound here & on other forums. It's Italian, so there's a couple of quirks. After you've done it a few times, you'll know how & it will be simple. The fueline runs from the red elbow on the underside of the in-tank fuel pump, where you have just disconnected it. The hose runs to a t-piece, & from there to each injector. The injectors pull out with a little effort - they are held in with o-rings. Check for leaked fuel, check the o-rings too. If you can't be sure where it starts, try spreading some talcum powder around, reconnect everything, start the bike, stop it, lift up the tank & see if you can find evidence. 2 overflow hoses come off the bottom on the Breva's tank, the one nearest the seat is the drain for water, the one inboard is the fuel overflow. Ensure these hoses are in good condition (replace if not) AND CONNECTED. They just push on & can come adrift - if you overfill the tank, it's supposed to go down that hose, so ensure its pushed on. Let us know how you go.
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Online bmc5733946

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Re: Breva 750 leaking gas from left side
« Reply #3 on: December 06, 2021, 06:09:14 AM »
There is a plastic tee in the fuel line to feed the injectors that perishes and cracks over time, look there first. Don't ride the bike unless you like motorcycle flame!

Brian
1989 MILLE GT 
2004 BREVA 750     
1975  Convert

Wildgoose Chase Moto Guzzi

Re: Breva 750 leaking gas from left side
« Reply #3 on: December 06, 2021, 06:09:14 AM »

Offline MotoGuzzi750

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Re: Breva 750 leaking gas from left side
« Reply #4 on: December 08, 2021, 07:39:08 AM »
Best to take the tank off & have a look. (It's easy enough to learn how to disconnect the QD (quick disconnect), just follow the instructions that abound here & on other forums. It's Italian, so there's a couple of quirks. After you've done it a few times, you'll know how & it will be simple. The fueline runs from the red elbow on the underside of the in-tank fuel pump, where you have just disconnected it. The hose runs to a t-piece, & from there to each injector. The injectors pull out with a little effort - they are held in with o-rings. Check for leaked fuel, check the o-rings too. If you can't be sure where it starts, try spreading some talcum powder around, reconnect everything, start the bike, stop it, lift up the tank & see if you can find evidence. 2 overflow hoses come off the bottom on the Breva's tank, the one nearest the seat is the drain for water, the one inboard is the fuel overflow. Ensure these hoses are in good condition (replace if not) AND CONNECTED. They just push on & can come adrift - if you overfill the tank, it's supposed to go down that hose, so ensure its pushed on. Let us know how you go.

Thank you very much for the detailed info.

1. I could locate/see that the leak is at T-junction. I saw fuel leaking at where the single pipe/hose fits on the white-plastic T-junction.
Next, I will be removing the tank, disconnect the hose at leaking point and try to repair it/clamp it firmly etc.

2. I saw that the two overflow hoses are NOT connected. Hmm..I wonder why, and what are the implications.

Offline MotoGuzzi750

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Re: Breva 750 leaking gas from left side
« Reply #5 on: December 08, 2021, 07:43:36 AM »
There is a plastic tee in the fuel line to feed the injectors that perishes and cracks over time, look there first. Don't ride the bike unless you like motorcycle flame!

Brian

Thanks. I saw the leak at plastic T, before it feeds the two hoses going to injectors. Any tips for repairing the leak ?
I am thinking just cut off the leaking hose and re-fit and clamp it firmer. Hope this is enough to stop the leak. We will see.
I actually rode the bike multiple times, since I didnt notice the leak until last ride. I was lucky I guess.

Online bmc5733946

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Re: Breva 750 leaking gas from left side
« Reply #6 on: December 08, 2021, 12:17:19 PM »
Finding a comparable tee is not easy. I used one that I now find is incompatible with fuel injection. It has been there for several years but I never checked if it was rated for fuel injection pressure.
This is where I will start next.
Moto Guzzi   Part number=    AP8120116

https://www.harpermoto.com/?match=all&subcats=Y&pcode_from_q=Y&pshort=Y&pfull=Y&pname=Y&pkeywords=Y&search_performed=Y&q=AP8120116&dispatch=products.search&security_hash=81a5d9e3d5468b387d702bad8873081b

Brian
« Last Edit: December 08, 2021, 12:21:49 PM by bmc5733946 »
1989 MILLE GT 
2004 BREVA 750     
1975  Convert

Offline malik

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Re: Breva 750 leaking gas from left side
« Reply #7 on: December 08, 2021, 02:13:53 PM »
I would buy a whole new fuel hose. The originals seem to be made of a few layers welded together in a special production process. A knowledgable auto mechanic advised me similar are occasionally found in cars, there is a particular name for the process (that I don't remember), and after serious investigation he found that they can't be repaired reliably. Bite the bullet & buy a new one. Note that the injectors do come out with a bit of pressure - they are held in with o-rings.

If you do find a method to fix the hose, let me know. I've a couple of hoses broken at the T I would not mind rescuing.
2010 V7 Classic, 2014 V7 Special
1996 1100 Sport Carb (in NZ), 2004 V11 LeMans (in UK)
Carberry Enfield V-Twin, 2008 Royal Enfield Electra, 2006 RE Electra 535

Online bmc5733946

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Re: Breva 750 leaking gas from left side
« Reply #8 on: December 08, 2021, 03:24:03 PM »
On mine the plastic tee was broken. To slide the plastic hose over the fitting use hot water or a heat gun on low heat.

Brian
1989 MILLE GT 
2004 BREVA 750     
1975  Convert

Offline guzzisteve

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Re: Breva 750 leaking gas from left side
« Reply #9 on: December 08, 2021, 04:57:00 PM »
While you have the tank off, lay bike over on it's right side against a wall and crawl under from RH side to adjust clutch arm. It's right in front of swingarm.
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Offline MotoGuzzi750

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Re: Breva 750 leaking gas from left side
« Reply #10 on: December 12, 2021, 09:03:54 PM »
There is a plastic tee in the fuel line to feed the injectors that perishes and cracks over time, look there first. Don't ride the bike unless you like motorcycle flame!

Brian

Update:

The original leak was from single hose going into plastic tee. I broke the plastic tee while hoping to make the connection tight enough to prevents leak. Purchased a new tee ( its 1/4 inch plastic tee , that i searched and ordered from Amazon ) and three 1/4-1/5 inch clamps from Home Depot, as I didnt want to deal with original clamps.
The leak has stopped with the new plastic tee and clamps. I also decided to cut off a 1inch piece from end of hose, as it looked worn/cracked/beaten up.
No leak after a short ride of 15-20 mins. Currently struggling to get the tank bolt aligned to re-install the tank. Thanks.
 

Offline MotoGuzzi750

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Re: Breva 750 leaking gas from left side
« Reply #11 on: December 12, 2021, 09:10:06 PM »
I would buy a whole new fuel hose. The originals seem to be made of a few layers welded together in a special production process. A knowledgable auto mechanic advised me similar are occasionally found in cars, there is a particular name for the process (that I don't remember), and after serious investigation he found that they can't be repaired reliably. Bite the bullet & buy a new one. Note that the injectors do come out with a bit of pressure - they are held in with o-rings.

If you do find a method to fix the hose, let me know. I've a couple of hoses broken at the T I would not mind rescuing.

I just cut-off hose about 1inch at the end. And I searched for a clamp with screw which was about the size of diameter of hose.
I found one in Home Depot plumbing/HVAC dept. These clamps were easy to instal as you just tighten the screw. I started the bike and looked for leaks. No leaks were found. Hope this helps. Let me know if any questions about my repair, and I would be happy to help.

Offline OldMojo

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Re: Breva 750 leaking gas from left side
« Reply #12 on: December 13, 2021, 07:52:31 AM »
Using screw clamps on pressurized fuel line is generally frowned upon these days. Sometimes accessibility demands it, but better to play it safe with a crimp style.

I bought this set on Amazon. It'll probably last me the rest of my life, and comes with the crimper/remover tool.




https://www.amazon.com/Keadic-Stainless-Assortment-Securing-Automotive/dp/B07HF2LZJF/ref=sr_1_3?keywords=ear+hose+clamps&qid=1639401440&sr=8-3

I loathe having to interrupt a repair to run down some stupid little doohickey. An excellent "life hack" for me has been to obtain assortments of:

-clamps
-fuses
-wire terminals
-speed nuts
-those stupid plastic body panel rivet thingies

Every time you can reach into the bin and avoid yet another scavenger hunt for this kind of stuff, you'll thank your past self for being such a genius!  :cool:

Thanks to Amazon and the like, such assortments aren't as prohibitively expensive or hard to find as they once were.
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