750 Breva Fuel Filter, -or what?

[vwdsl]

Found a thread from a few years ago posted by lostinthemarket about 750Breva supposed EFI problem. It ended up being cracked fuel hose inside his tank. His symptoms sounded much like my symptoms so I pulled the pump assembly out of my tank to check it out. My fuel filter and hoses appear to be OEM and pristine. The screen on the fuel sump is clean as a whistle so it is hard to believe the outlet filter would be plugged. What would be the next step?
My symptoms are this: Few weeks ago, bike was not running smoothly after a long ride. Condition was gone the next time I rode. About a month later, I went on a 150 mile ride About halfway, I bought gas at an extremely remote self-service that I doubt sold much higher octane gas. Yeah, it had ethanol in it but I needed fuel bad. Bike ran fine all the way home. After a stop on the next ride, it gave a backfire when cranking. From that point on, I was worried about getting back home. It was mostly running on one or one-and-a-half cylinders, although it would pick up and run okay briefly. Messing around with it, I found it was the left cylinder that wasn't getting up to temperature. No EFI warning light and no codes thrown with GuzziDiag. One thing I did find removing the gas tank: Tank vent line that goes through a check-valve(?) to the evaporative canister was squeezed shut from getting pinched under something in the past. The second vent hose (?) or drain hose(?) that just goes behind the starter and open-terminates below was plugged with corrosion inside the metal fitting in the tank. Surely these wouldn't be the source of my problem? Looked like they had been that way for a long time.
Comments and suggestions?

[malik]

On the Breva, it is usually the aluminium nipple at the rear of the tank - the water overflow - that clogs up with corrosion first. It blocks, stops the rain water & washing water flowing away, the water spills into the tank, mixes with the fuel, and can, in severe cases, rust some of the pump components.

It's best if you unblock that drain. Which means tank off, fuel out, at least. I picked up a hand drill to use for just this problem - to clear the corrosion from the nipple. With care, the inner of the drain tube moulded into the tank can be cleared with an old clutch cable inner, then air both ways. Do double check the pump for rusty bits. A mate's Breva had this problem, & we couldn't get it to run properly - worked perfectly with a different fuel pump. Then we found the rust on the old one. Preferably, discard the old fuel, & use new, but if that's not appropriate, a cap full of metho should dilute the water in the mix.

FWIW, I've found lower octane rated fuels do not perform significantly differently on these engines from the higher octanes. Ethanol though, is another thing. Avoid it if you can.

[guzzisteve]

While it's apart swap out filter w/metal one and new hose SAE30R10, FI clamps small enough to tighten up good. Open the vent hose that goes to check valve. They were replacing the grey check valve for a blue/yellow one that is open flowing. Open up rusted port for cap drain. Then run through some FI cleaner in fuel. Should run better.

[vwdsl]

While it's apart swap out filter w/metal one and new hose SAE30R10, FI clamps small enough to tighten up good.

Thanks. Have seen this in other posts but it is not clear to me if the advise is to swap BOTH hoses, the upstream "corrugated" hose as well as the downstream hose with generic SAE30R10 hose. Wil generic hose work okay for the upstream hose? Also, some recommend a generic NAPA Gold 3032 filter as opposed to OEM part. I vote for the one that has the longest service life, whichever one that is.

[drdwb]

Check the fuel injectors connections in the cap, I got one used that had this problem, the previous owners had taken it to several Guzzi mechanics and spent a lot of money swapping components, many different maps. Finally taking injectors out and watching to see the mist come out I found a loose connection in the cap. Also on the Left side. This took about 2 months of messing with it. Guzzi Dia did not find it but it helped.

[malik]

It's usually just the hose on the downside of the filter that needs changing. The corrugated hose appears to be quite robust inside there. It's still fine on the V7C - 10 years on - and it's been fine also in the earlier Breva's & Nevadas I've come across. Do use good clamps, in stainless, preferably with rolled edges to avoid cutting into the hose. I know people who are happy with the oetiker clamps & have purchased the tool.

Any of the listed filters should be OK - I think there's a list in the Files section of Moto-Guzzi-750@groups.io - both the Mann & the Mahle I've used are still working since insertion.

[vwdsl]

Check the fuel injectors connections in the cap, I got one used that had this problem, the previous owners had taken it to several Guzzi mechanics and spent a lot of money swapping components, many different maps. Finally taking injectors out and watching to see the mist come out I found a loose connection in the cap. Also on the Left side. This took about 2 months of messing with it. Guzzi Dia did not find it but it helped.

drdwb, I read your thread about these woes with great interest. It looks like I have to pull the injectors just to get the connectors off to check. Externally, the errant left cylinder connector looks fine. It is the right one that looks funky. The right injector harness is routed over a frame member and is as tight as the proverbial banjo string. Wish I could find some pics of a virgin 750 Breva showing the factory routing of the wiring harness and sub-harnesses. Hose routings would be helpful as well. My bike has obviously been severely cobbled in this regard.

[Kiwi_Roy]

I'm going to suggest something totally different, Something wrong with the stand switch which causes the main injection relay to flicker off.
Pay special attention to the idiot lights while its running badly. I'm probably completely wrong but seem to recall my VII Sport doing that.
The ignition switch as well. try exercising that to get a better connection next time it occurs.
https://www.thisoldtractor.com/guzzi007/schematics/2004_750_Breva.gif

[cee2cee]

Some good information here!  I pulled my tank when i bought my Breva 750 about 9 years ago and had a devil of a time getting it back on.  Now it it time to pull it again as the water overflow is clogged and fuel filter needs changed, so I am wondering what everyone else's expereince has been with re-installing the tank?  Any tips?

[Mackers]

I haven't had any trouble replacing the B750 tank.  I always put rubber grease on the two positioning bungs and take my time getting the tank into place.

[Muzz]

I'm going to suggest something totally different, Something wrong with the stand switch which causes the main injection relay to flicker off.
Pay special attention to the idiot lights while its running badly. I'm probably completely wrong but seem to recall my VII Sport doing that.
The ignition switch as well. try exercising that to get a better connection next time it occurs.
https://www.thisoldtractor.com/guzzi007/schematics/2004_750_Breva.gif

Exactly my symptoms Roy.  Idiot light flicking on and off first.  Problem with switch.