Bike died on me...Next day was fine.

[dividedbyzach]

Hey guys

Anybody have some insight on this?

Went for a long-ish bar hop on Wed with my club - Venice to Echo Park, stopping to see some bands/bars along the way. On the way home, we stopped at a light and my bike just fizzled out. I tried to rev the throttle and it just didn't catch, almost felt like it was out of gas or there was a blockage of some sort. All systems died and the bike stalled.

It started up again but I had to rev it REALLY hard to get it to catch and move. Fortunately, I was only about 10 blocks from home and I sputtered to my driveway.

The next morning it started right up and idled fine. Haven't taken it for a spin yet because I don't have time to get stranded today (pregnant wife and all). I checked the engine and transmission fluid and both seemed fine. The gas is low, maybe 1/3 full, but I can see it sloshing around so it's not empty.

What should I check?

1970 Ambo btw

[sib]

Does the bike have an blood alcohol-sensing ignition disabler?

[lucian]

Water in the Gas, float bowls ?

[dividedbyzach]

Does the bike have an blood alcohol-sensing ignition disabler?

buahahhahaa

[rocker59]

Water in the Gas, float bowls ?

My first thought, to.

[John A]

If you use glass fuses in the headlight bucket they can separate and loose contact. Better to use the VW style. The ignition switch contacts can wear out. Tank venting should be checked.

[oldbike54]

 Dirty screens in the petcocks , or maybe the Keebler Elves that really keep old motorbikes running had gone to lunch , dunno

  Dusty

[twhitaker]

There are also very fine mesh screens at the carb inlets that are worth checking.

[fotoguzzi]

crud from bottom of gas tank gets sloshed, plugs up the petcock screen, after it sits over night the crud settles back to bottom.?
or
tank not venting?

[dividedbyzach]

Well...I did recently take the tank off to do some work so maybe the vent tube is pinched?

I also just washed it, so maybe something got wet?

And I also was messing with the fuses in the headlight bucket, so maybe I should replace all?

[Chuck in Indiana]

Well...I did recently take the tank off to do some work so maybe the vent tube is pinched?

I also just washed it, so maybe something got wet?

And I also was messing with the fuses in the headlight bucket, so maybe I should replace all?

All of the above. That's a tough one to diagnose over the internet.

All systems died

says electrical, generally the ignition switch.. but then you said it started and ran poorly, which says fuel delivery. <shrug>
The ignition switch is rebuildable and should be rebuilt on a machine that old. Same deal for the fuse block, needs cleaned with a wire brush and new fuses installed. Pull the petcocks out of the tank and have a look at the filter screens. This will also serve the purpose of getting out any water/gunk in the tank.
Report back.

[Aaron D.]

I'm thinking rust flakes in the fuel system, it happened to me on an old loopframe.

[pehayes]

I'm thinking dirty fuel filler cap.  The entire tank only vents through a pinhole in the cap.  As fuel goes down, the tank develops a vacuum and the carb bowls run dry.  Open the tank to inspect the fuel level and the bike runs perfectly until you buy your next tank.  Very common problem with LoopFrame Guzzi.  Mostly common to those who polish and shine and plug the cap's vent hole with wax.  The Texas Turnip never had such a problem.

Patrick Hayes
Fremont CA

[Chuck in Indiana]

True, but..

All systems died

Unless they really didn't..

[Markcarovilli]

Had same problem with my Eldo - first thought it was gas cap and drilled out small hole which seemed to help for a while.  Problem kept recurring and I finally found it to be the push/pull coil switch on right side of the dash.  It was opening intermittently and random.  Cleaned up with Deoxit and have not had a problem since.

Just another data point.....

Mark

[Cam3512]

There is no vent tube from the tank.  Make sure your cap is venting.  If it happens again, loosen the gas cap.

If you washed the bike, moisture/water under the distributer cap?  Hit the inside with WD40.

[dividedbyzach]

True, but..Unless they really didn't..

You may be right. Happened so quick it seemed like everything died, but it could have been my imagination. It was the last stop of the night after all 

[dividedbyzach]

Great comments on the gas cap, guys. Hopefully that's the simple (non) fix, because it seems to have fixed itself after I took off the cap to inspect the fuel level...