Breva 750 cuts out at idle: diagnosis sound right to you?

[Rhodan]

I'm looking around for another bike (I should just wait until the 85TT comes out but...)
I saw this one listed.  Inexpensive.  And of course not working correctly. ;)  And of course the person isn't local.

Here's the description of the problem and the diagnosis.  Sound plausible or a song-n-dance?  My mechanical/electrical skills are low, hence the question.

"The bike starts but cuts out when idling. I just brought it to the shop and their diagnosis is that the bikes needs a new stator and rectifier. I would do this myself but I am living on the east coast and don't have the time to fix it while home in the PNW. "

[Rhodan]

I'll add that if a shop diagnosed it, I can't imagine it would cost a ton for the shop to fix it (and then this person would get $ for the bike).  I bet they'd even do it if the person was remote.  So there's likely more going on than the listing is indicating or it's just total hogwash.

But hope (cheap hope ;)  ) springs eternal.

[pat80flh]

First sign of a bad stator/regulator would be a dead battery, if the battery got low enough to make it stall at idle it probably would not restart. Not to say they couldn't be bad but I'd bet there's more to it.

[Rhodan]

Yeah, no charge to the battery, makes sense.  I think $$ (or in this case $) got in my eyes. 

Probably one I should leave for someone who actually knows what they're doing.  Appreciate the reply.

[sign216]

Rhodan,

An issue w the 750 bikes of your era was that the rectifier grounded via it's connection to the frame, but ... since both the rectifier and frame were painted, this interfered with the ground.  Led to all kinds of elec. problems, so later models had a dedicated ground wire from the rectifier direct to the battery (-) terminal. 

The short answer was to sand the rectifier mount, so it had a good connection.  Sounds like your unit is too far gone to save, but it's food for thought.

Please keep me posted.  I love the old Brevas.

Joe

[malik]

The twin throttle body small blocks (Breva & V7C) are supposed to idle at 1100 rpm +/- 100. If the idle is set low & is lumpy, it's likely to cut out below 900rpm. Does the fast idle lever (choke) work to increase the idle speed & keep it running? If so, it could be throttle body balance is out, or someone fiddled with the "sacred screw" or played with the air bleeds. If not, possibly something in the fuel supply, or something in the spark system. Either way, if is likely to require working through to sort it. Can't really do it from an armchair, so the price has to reflect the fact that it's not a working bike. It's Italian, it's a Guzzi, so frustration comes along with. If you are prepared for that, build it into the price.

[Chuck in Indiana]

"sacred screw"

As far as I know, the small blocks don't have one?

[malik]

That little one on the left hand TB that's set electrically at the factory.

[timonbik]

Check the 20amp charging fuse on the side of the battery under the side cover.  Easy to short out especially if someone has been boosting the battery.  Bike will not idle and runs rough with low voltage,  Idiot lights start flashing.

Tim

[Rhodan]

Thanks guys for the additional ideas.  I looked around and there are other Brevas not too far away that are fully working and the price is close-ish.  Might pursue them instead if I decide to go the Breva route.

I'm going to Moto International this Saturday for one last look before they close.  Who knows...maybe I'll get to say "look what followed me home." ;)

[Muzz]

Rhodan,

An issue w the 750 bikes of your era was that the rectifier grounded via it's connection to the frame, but ... since both the rectifier and frame were painted, this interfered with the ground.  Led to all kinds of elec. problems, so later models had a dedicated ground wire from the rectifier direct to the battery (-) terminal. 

The short answer was to sand the rectifier mount, so it had a good connection.  Sounds like your unit is too far gone to save, but it's food for thought.

Please keep me posted.  I love the old Brevas.

Joe

Didn't know about that one Joe. Thanks.

No problems with mine at all but good to know about.

[Kiwi_Roy]

Thanks guys for the additional ideas.  I looked around and there are other Brevas not too far away that are fully working and the price is close-ish.  Might pursue them instead if I decide to go the Breva route.

I'm going to Moto International this Saturday for one last look before they close.  Who knows...maybe I'll get to say "look what followed me home." ;)

What time are you going
If you see an old fart on a black Griso with BC plates that's me
I'll probably be there by 10:00

[Rhodan]

Probably in the morning, 9-10ish before the traffic gets too crazy.  I'll check when I get there and see if you're around.