Bike ran yesterday, won't start today

[Drtbik]

Looking for some help here.  1997 Bumblebee standard.  10K miles.  Bought last spring, changed all the fluids and regressed splines on final drive, replaced all the rubber there (O-rings and rubber wheel dampers) then got short notice orders and deployed for six months.  Wife told me it began leaking fuel when she periodically started it to keep battery charged and fluids flowing, had her turn it off, connect battery to tender and it sat the last 2 months before I got home.

I pulled the carbs a couple of weeks ago, used a heated 30L ultrasonic cleaner + all balls rebuild kit and replaced all the O rings for the fuel and air components.  Installed new in line fuel filter, and a Dan-Marc fuel shut off.  Installed Red Eye desmog.  Fresh fuel in the tank.  Did some electrical bling - a new LED headlight and flashers from Eagle lights with a custom dynamics relay and a brighter brake light (that was the most recent change - the electrical bits).  Bike got a new OEM air filter.  Everything tightened to spec per the shop manual. 

Bike started and ran pretty well after the carb rebuild, took it out and rode it for a couple of hours.  Sat for a bit while I awaited parts for the light upgrade.  Started and ran a little rough 2 days ago.  I ordered and received a 6 cylinder Digi Sync which I wanted to use today to synchronize the carbs, but the bike decided not to play nicely anymore.

Yesterday it would crank nice and strong, would start but only catch for a half a second if it was choked, but then then it died.  It would not catch at all if not choked.  Today, same story.  Went through the forums and tried various trouble shooting methods and discovered the following:

(Spark) Present on all 6 cylinders - battery bought and installed 5/20 and is currently recharging after cranking over for a while today.  Tried a brand new LiFePo4 battery from my VFR and it cranked about the same and had same characteristics (turn over a few times after cranking with choke, wouldn't run).

(Fuel)  Gas in the bowls on 2, 4, and 6.  Didn't really have any fuel in the bowls on the right side.  This was done with the bike on the side stand, so maybe fuel wouldn't come out of the drain if it was tilted?

(Air) New, Clean air filter.  Vacuum lines all checked and connected, seemed to be fine.

I wondered if my DanMarc fuel shut off is the problem, but I placed a screwdriver on it and I can feel the light pop of the valve/solenoid when the key is turned on/off, so I don't think it's that. 

My suspicion is that there is something going on with the fuel delivery, like it's only running on the 3 cylinders on the left side, but I wanted to check with you all to see if that is the community census.  Really want to get the bike running, it's supposed to be 70 degrees this week in Sunny Las Vegas!

Thanks all for reading and thanks in advance for helpful advice!!

[The emperor has no clothes]

Sounds like a failing petcock to me. I would put in a cover set rebuild. Or at least test the petcock to see if it’s flowing well enough.

[The emperor has no clothes]

If it is the petcock failing, and you don’t want to wait for the rebuild kit. There is a way to modify the petcock to make fully manual (no vacuum shut off) being that you have a DanMarc installed, that shouldn’t be a worry.

[Chrisj CMA]

In line filters are not needed and have been the problem for some in the past

[sandy]

On line filters are not needed and have been the problem for some in the past

The inline filter and solenoid valve can cause problems. If the scope of the tubing drops, you’ll have the issues you describe. Replace with the original tube and try again.

[Drtbik]

I forgot to mention (so many upgrades/mods) the petcock is new as of 11 months ago, and I bought a fuel line quick disconnect that had the fuel filter already installed in it. The old gas line had a fuel filter on it, so I thought it was all oem-like.

Thanks, all, I’ll give it a shot!

[The emperor has no clothes]

I forgot to mention (so many upgrades/mods) the petcock is new as of 11 months ago, and I bought a fuel line quick disconnect that had the fuel filter already installed in it. The old gas line had a fuel filter on it, so I thought it was all oem-like.

Thanks, all, I’ll give it a shot!

That sounds like the problem. Those quick disconnect lines and a filter on top of it are surely restricting the flow. Any extra length of fuel line creates problems on these bikes. The line needs to be short enough where it’s a pain to get it on the petcock.

[dpcarson]

Looking for some help here.  1997 Bumblebee standard.  10K miles.  Bought last spring, changed all the fluids and regressed splines on final drive, replaced all the rubber there (O-rings and rubber wheel dampers) then got short notice orders and deployed for six months.  Wife told me it began leaking fuel when she periodically started it to keep battery charged and fluids flowing, had her turn it off, connect battery to tender and it sat the last 2 months before I got home.

I pulled the carbs a couple of weeks ago, used a heated 30L ultrasonic cleaner + all balls rebuild kit and replaced all the O rings for the fuel and air components.  Installed new in line fuel filter, and a Dan-Marc fuel shut off.  Installed Red Eye desmog.  Fresh fuel in the tank.  Did some electrical bling - a new LED headlight and flashers from Eagle lights with a custom dynamics relay and a brighter brake light (that was the most recent change - the electrical bits).  Bike got a new OEM air filter.  Everything tightened to spec per the shop manual. 

Bike started and ran pretty well after the carb rebuild, took it out and rode it for a couple of hours.  Sat for a bit while I awaited parts for the light upgrade.  Started and ran a little rough 2 days ago.  I ordered and received a 6 cylinder Digi Sync which I wanted to use today to synchronize the carbs, but the bike decided not to play nicely anymore.

Yesterday it would crank nice and strong, would start but only catch for a half a second if it was choked, but then then it died.  It would not catch at all if not choked.  Today, same story.  Went through the forums and tried various trouble shooting methods and discovered the following:

(Spark) Present on all 6 cylinders - battery bought and installed 5/20 and is currently recharging after cranking over for a while today.  Tried a brand new LiFePo4 battery from my VFR and it cranked about the same and had same characteristics (turn over a few times after cranking with choke, wouldn't run).

(Fuel)  Gas in the bowls on 2, 4, and 6.  Didn't really have any fuel in the bowls on the right side.  This was done with the bike on the side stand, so maybe fuel wouldn't come out of the drain if it was tilted?

(Air) New, Clean air filter.  Vacuum lines all checked and connected, seemed to be fine.

I wondered if my DanMarc fuel shut off is the problem, but I placed a screwdriver on it and I can feel the light pop of the valve/solenoid when the key is turned on/off, so I don't think it's that. 

My suspicion is that there is something going on with the fuel delivery, like it's only running on the 3 cylinders on the left side, but I wanted to check with you all to see if that is the community census.  Really want to get the bike running, it's supposed to be 70 degrees this week in Sunny Las Vegas!

Thanks all for reading and thanks in advance for helpful advice!!

OK brother, looks like you are in Vegas.  Are you at Nellis? 

I would start with fuel delivery

Make sure the enricher cables and bracket are properly connected to all carbs.
Since you did the desmog I am assuming you pulled off the fuel drain tubes also.  Connect a hose to the fuel drain on the carbs and open the drain to make sure there is fuel making it into the bowls.  I also do it in a clear plastic bottle so I can see if there is trash and rust in it.  I would do that to see if every bowl is getting fuel.  IF not, you have tracked that down.  I have had brand new float valves with weak springs and have had one stick.
Is there any rust that you can see in the tank?  With the new gas put in there it could mean rust broke free.  If so, next check is the fuel screen on the petcock. 
If you see rust buildup on the fuel screens then I would think it may have made it into carbs. IF that happens, even if you just rebuilt them you probably need to at least check the float valves and pull the jets and drop them in the ultrasonic.  Unfortunately happened to me.  1 week after a rebuild on one of mine.   

[Jims99]

I agree with Chris, sandy and meathead. Do a way with disconnect, filter and keep fuel line as short as you can. Any restrictions or dip in line can cause problems. Even if all was well at first, an air bubble can stop or restrict fuel flow. I bought a bike that had the same problems and found it had a longer fuel line and inline filter. Took filter off and shortened line, no problems for the last 8000 miles.

[Foozle]

02-17

Maybe I'm simply missing this in his post, but I don't see where he's used any type of quick disconnect.  Having said that, the DanMarc and/or inline fuel filter are possible causes - although I know others have run them both without issue.

I removed my DanMarc after a wire rubbing shorted things out (my error, not the DanMarc) - causing the valve to intermittently close.  However, I was concerned its placement was causing a dip in the fuel line - and just decided to remove it altogether. (Also, make sure the DanMarc has the larger orifice to allow maximum fuel flow; a search of the archives will yield the correct model number; look for a thread my MarkT).

Lastly, while it makes installation easier, you really can't add any length to the OEM fuel line without (seemingly) tempting fate.

Long story short, I removed the DanMarc (no inline filter) - replaced the OEM petcock - and now RELIGIOUSLY turn my fuel off.  No issues thus far.

As always, YMMV.  Good luck.

Terry 

[Tfrank59]

Just out of curiosity are you certain it’s fuel delivery? Did you check for spark and stuff

[Drtbik]

Well, thanks to all of you, I took off the tank and air box and started from the fuel rails and worked my way backwards.  No gasoline at any point!  Gas wasn't getting into the lines from the petcock at the very start of it!  So, thanks to Meathead for the heads up on the petcock modification.  I did that and reinstalled the now working and totally manual petcock, and for giggles, disconnected the fuel lines from the carbs back and hooked it up to the tank sitting on a couple of sawhorses (off of the bike and over a wide mouth funnel into a gas can).  I tested the petcock (no leaks, whew!) and jerry rigged some power to the Dan Marc and the gas flowed freely and easily.  No flow restriction issues. So I kept the fuel filter and quick disconnect. 

So I connected everything back on the bike, replaced the air box (what a pain in the neck that is!!) and tank, crossed my fingers, choked the bike and thumbed the starter...  Started right up!

20 minutes later, the carbs were all synced and I was putting on my helmet to take 'er for a ride in the lovely 60 degree weather.

Thanks all! 

[The emperor has no clothes]

Well, thanks to all of you, I took off the tank and air box and started from the fuel rails and worked my way backwards.  No gasoline at any point!  Gas wasn't getting into the lines from the petcock at the very start of it!  So, thanks to Meathead for the heads up on the petcock modification.  I did that and reinstalled the now working and totally manual petcock, and for giggles, disconnected the fuel lines from the carbs back and hooked it up to the tank sitting on a couple of sawhorses (off of the bike and over a wide mouth funnel into a gas can).  I tested the petcock (no leaks, whew!) and jerry rigged some power to the Dan Marc and the gas flowed freely and easily.  No flow restriction issues. So I kept the fuel filter and quick disconnect. 

So I connected everything back on the bike, replaced the air box (what a pain in the neck that is!!) and tank, crossed my fingers, choked the bike and thumbed the starter...  Started right up!

20 minutes later, the carbs were all synced and I was putting on my helmet to take 'er for a ride in the lovely 60 degree weather.

Thanks all! 

Excellent ! Thanks for posting the results.

We should ride some time 

[Tfrank59]

Yeah, thanks for the follow up. Glad everything’s working good for you. Ride safe.

[Jims99]

FYI. If you run out of gas and hit reserve, and still doesn’t seem to help, air bubbles in the fuel line can stop the flow of gas when on reserve. This is the reason they say to keep lines short and down hill. Dips in the line are no good once air gets in.
Thanks for results post. Glad it was simple fix.

[gordonv]

I'm glad you followed the suggestion of verifying if you had fuel all the way to the carbs. Some have had problems with all those none OEM items, and others swear by them.

I wonder if your issue with the new petcock was a vacuum leak, and it wasn't opening?


Since you're a new Valk owner, have you figured out the chock (fuel enricher)? You want to turn it on till resistance, then force it another 1/2" or so. Could also watch the carbs and see the slides move. It feels like your trying to break it, but it takes a lot to move those 6 carbs together.

Thanks for posting what you found out to fix it.

[Willow]

Well, thanks to all of you, I took off the tank and air box and started from the fuel rails and worked my way backwards.  No gasoline at any point!  Gas wasn't getting into the lines from the petcock at the very start of it!  So, thanks to Meathead for the heads up on the petcock modification.  I did that and reinstalled the now working and totally manual petcock, and for giggles, disconnected the fuel lines from the carbs back and hooked it up to the tank sitting on a couple of sawhorses (off of the bike and over a wide mouth funnel into a gas can).  I tested the petcock (no leaks, whew!) and jerry rigged some power to the Dan Marc and the gas flowed freely and easily.  No flow restriction issues. So I kept the fuel filter and quick disconnect.  

So I connected everything back on the bike, replaced the air box (what a pain in the neck that is!!) and tank, crossed my fingers, choked the bike and thumbed the starter...  Started right up!

20 minutes later, the carbs were all synced and I was putting on my helmet to take 'er for a ride in the lovely 60 degree weather.

Thanks all!  

You made a quick jump to blaming the petcock.  If you put on the petcock rebuild kit check one more thing.  Be sure you don't have a leak in the vacuum hose to the petcock.  If you're losing vacuum through a leak the petcock will not be triggered to deliver.

[The emperor has no clothes]

Well, thanks to all of you, I took off the tank and air box and started from the fuel rails and worked my way backwards.  No gasoline at any point!  Gas wasn't getting into the lines from the petcock at the very start of it!  So, thanks to Meathead for the heads up on the petcock modification.  I did that and reinstalled the now working and totally manual petcock, and for giggles, disconnected the fuel lines from the carbs back and hooked it up to the tank sitting on a couple of sawhorses (off of the bike and over a wide mouth funnel into a gas can).  I tested the petcock (no leaks, whew!) and jerry rigged some power to the Dan Marc and the gas flowed freely and easily.  No flow restriction issues. So I kept the fuel filter and quick disconnect.  

So I connected everything back on the bike, replaced the air box (what a pain in the neck that is!!) and tank, crossed my fingers, choked the bike and thumbed the starter...  Started right up!

20 minutes later, the carbs were all synced and I was putting on my helmet to take 'er for a ride in the lovely 60 degree weather.

Thanks all!  

You made a quick jump to blaming the petcock.  If you put on the petcock rebuild kit check one more thing.  Be sure you don't have a leak in the vacuum hose to the petcock.  If you're losing vacuum through a leak the petcock will not be triggered to deliver.

I get an uneasy feeling when Willow and I agree. But..... today we do. (Maybe he changed his mind since he posted ?) If it was a new petcock (OEM) as you say, it’s highly unlikely it went bad this quick. Either way, I wouldn’t worry about it, since you have the electric fuel shut off.

[Mooskee]

I get an uneasy feeling when Willow and I agree. But..... today we do. (Maybe he changed his mind since he posted ?) If it was a new petcock (OEM) as you say, it’s highly unlikely it went bad this quick. Either way, I wouldn’t worry about it, since you have the electric fuel shut off.

But if like Willow suggest, there is a vacuum leak in the #6 vacuum tube going to the petcock, it should be corrected. If the petcock is now always open because of the mod, he would just put a cap on the #6 vacuum port.

[Drtbik]

I took the entire fuel delivery system off the bike from the tank to the hoses that connect to the left and right fuel rails (tubes?).  Connected my mighty-vac vacuum to the petcock, disconnected each item from end to start and the problem was the petcock.  Scientific method, or something like that, right? 

Did the petcock mod, capped off the vacuum tube to #6, tested each part going back together, tons of fuel flowing without any restrictions.  Wasn't a quick jump, per se, I just didn't type the whole thing out, and allowed you all to think I jumped, I guess.

At the end of the day, I'm very happy with the outcome!

[Jersey]

I took the entire fuel delivery system off the bike from the tank to the hoses that connect to the left and right fuel rails (tubes?).  Connected my mighty-vac vacuum to the petcock, disconnected each item from end to start and the problem was the petcock.  Scientific method, or something like that, right? 

Did the petcock mod, capped off the vacuum tube to #6, tested each part going back together, tons of fuel flowing without any restrictions.  Wasn't a quick jump, per se, I just didn't type the whole thing out, and allowed you all to think I jumped, I guess.

At the end of the day, I'm very happy with the outcome!

Thanks for letting us know how it worked out. Glad it's fixed.