Topic: Will 550 run on dead battery?

[TwoTired]

All I am saying is that you cannot categorically say that these bikes will not run without a battery.

I never said they couldn't run without a battery.  I said they needed a good battery to run and spared the reader several pages of electrical load budget equation data to demonstrate the point.  (Remember the topic heading, 550 AND dead battery?) A bad (dead) battery will load the system and the bike WILL die, as will bikes that have the stock electrical loads, which yours doesn't.  Does context mean anything to you?  Do you really think that no battery equates to a dead battery?

Still, I admit I have little/no experience with the 350F, apart from the data I see in the manuals.  So, you stripped down your electrical loads on your bike to prove a point.  Fine.  Do you really think that helps other people, without explaining what you did to make that happen?  If not, then what's the real point of your post? 

I fail to see how you helped anyone with your stunt and trickery.

[ajinreno]

"didn't intend to eat the red off of anybody's apple."

I don't think I've ever heard that before...i like it.

[seaweb11]

pretty descriptive. 

Sounds like a Dr Philism

[754]

Actually it does help..

 It may get someone home in a pinch. To me dead battery sorta meant the same as no battery.

 A while back I mentioned starting a cb750 on a hill with a battery that would barely light the neutral ight, and it was said that it would not work.

So I will ask the Q again that I did earlier in this thread.. will a cb750 run if you hook a 6 volt  or 9 volt battery to it to energize the excited field??

To me it would be a viable method to get home after you disconnect the lights. I am thinking it is still legal here to use the hand signal to slow down?..perhaps nick knows?

Any trick that gets you home is worth knowing..

[TwoTired]

I am thinking, with lights off, and adding 6 or 9 volts with like flashlight batteries.. it should be able to kickstart and run..(with points)


 Question being asked as an emergency, get you home or to a town measure..

Maybe, but...
Flashlight batteries don't usually provide a lot of current.  For spark, each stock coil draws about 2.5 amps.  And to boost the alternator into operation you need another 2.5 amps field current for the 550 (about 2 amps for the 750s).  Getting flashlight batteries to provide 5 amps (no lighting allowed), and still have a voltage potential (internal resistance specs) , is going to be iffy, unless you have quite a lot of fresh flashlights to rob batteries from and wire in series/parallel to get enough voltage AND current.

There are different types of batteries, of course.  Some types do better at providing current while maintaining voltage than others, but the image I got from your suggestion was of the standard D size.

A dead motorcycle battery is very different from no battery, electrically speaking.  I dead battery almost always tries to accept energy, whether or not it is capable of storing it.  Therefore, it consumes energy from the charging system or any power source you attach to the system, in addition to the power consumed by essential devices to make the motor spark, and the alternator to make power.  "No battery" presents "no additional load" to any source providing power the the bike's systems.

Back to flashlight batteries:
One concern is why your battery is dead in the first place.  Something has failed right?  What?
 If the battery simply failed, that is one issue.  And, there are several failure modes that exhibit different electrical behavior. 
If it is depleted but otherwise good, it exhibits a certain behavior in the presence of injected energy, like sucking it up.  Unless it still has remaining potential higher than the power source you attached.  Then it will dump it's remaining energy into the batteries you attached. Charging a 6 or 9v battery from a higher source potential, means the batteries may accept a LOT of current as they try to reach equilibrium potential (again depending on their internal resistance).  Such high currents may also generate heat, enough to melt battery components and even bursting is possible, with an unpredictable level of violence.
Another concern, is if your charging system has quit and how.  If the rectifier has shorted, draining the battery into the stator coil resistance, flashlight batteries will dump their energy in them as well.   
If the charging system is ok , and you manage to get the engine running from a flashlight battery's "boost", the batteries you attached, having a lower potential than the alternator output, will begin to accept a charge.  Again, charging a 6 or 9v battery from a 12-14 V source potential, means the batteries may accept a LOT of current (again depending on their internal resistance).  Such high currents may also generate heat, enough to melt battery components and even bursting is possible, with an unpredictable level of violence.

There are a large amount of variables in the prescribed suggestion and scenario.  Enough to make a calculated outcome near impossible.  Or, enough to make the final determination a definite "maybe", or possibly "unlikely".

Anyway, it's been a long day for me, I'm going to have to stop the analytical progression at this point, in favor of sleep.

Cheers,

[upperlake04]

  Now that you're rested TT . another question along 754s (trick to get home).  Suppose one was on long trip, in an area without the availability of parts, and the charging system failed and the battery discharged completely.
   If an automotive battery was strapped to the bike with the leads mickey-moused to the bike battery cables, how far could one go with this setup? I know, lots of variables, but would it be in the ballpark of 20 minutes or 10 hours?
 

[754]

I was sort of thinking you could pull the helper battery off when it starts if it stays running?

A 5.5 amp with just running points and coils will probably go at least 2 hrs... stock 750 is 14 amp I think.. never used one in 20 years..

[TwoTired]

  Now that you're rested TT . another question along 754s (trick to get home).  Suppose one was on long trip, in an area without the availability of parts, and the charging system failed and the battery discharged completely.
   If an automotive battery was strapped to the bike with the leads mickey-moused to the bike battery cables, how far could one go with this setup? I know, lots of variables, but would it be in the ballpark of 20 minutes or 10 hours?
 

OK.  Let's state the problem a little differently.  Let's say someone steals your gas tank.  But, you find one from another bike (different from yours) you can strap on to your bike.  How far can you drive with that strap on tank of fuel?

Some things you need to know are:
The new tank fuel contents.
How fast the bike consumes fuel.


Same with the car battery scenario.  Is it charged?  How full?  What Size?  What will you operate on the bike during the discharge? Headlight? Turn sigs? Tail light?  Stop light? Instrument bulbs?  Will you disconnect the rectifier?  Will you disconnect the alternator field coil or the V regulator?

So, let's start to define some variables.  (We'll start with the easy ones.)  The only thing you need to make the bike move itself, is coil power. (Well, and gas.  But, that is a different challenge).  To obtain maximum distance you would disconnect all bike electrical loads except the coil power.  Each coil (stock 5 ohm) draws 2.5 Amps when supplied 12V.  It will draw more with higher voltage and less with lower voltage, per this formula: current (I) = Volts / resistance (ohms).  You have two coils that each operate during 195 degrees of crank rotation.  So, mostly you have only one drawing power at a time.  So, let's round up the current drain to 3 amps.  Ah, something to work with...

Next we need to know the battery capacity.  An Amp Hour (AH) rating would be good.  A 30 AH battery would run the bike about 10 hours, and probably longer.
Trouble is, auto batteries aren't intended to operate to depletion, so they don't give such an easy rating to use for this scenario.  No, they give CCA or cold cranking amps, because cars use large currents to get the car going and then have the alternator to operate the car on.  Car batteries are actually damaged during each deep cycle operation, btw.
A deep cycle battery is what you really want for this application.  But, I know, car batteries are more prevalent devices for the McGyver-ist, right?   It doesn't help much for this exercise that auto batteries are made in different sizes and this also relates to capacity.
The best I can do without real component specifications is a ball park a guess.  A crude generalization is that car batteries have a range of AH somewhere in the 25-100AH range.  Are you taking the battery from an econobox car with a small engine, a bigger luxury car (bigger engine) or a truck that needs a big battery to get it going?

So, pick an AH rating and divide it by the load you place on it to get an idea of howl long you have till it won't fire the plugs anymore.

Cheers,

[upperlake04]

 Wow - great reply TT and one I can understand. Will file that info into a (hopefully) retrievable part of my brain in case of future need. Could very well be the piece that salvages a tour.    Thank you 

[hapsh]

So I rerouted the fuel lines so that they go direct to the carbs and are downhill all the way.  Improved performance dramatically. However, it did starve for gas again when i was on the freeway for about 10 minutes. It did it for about 20 seconds where it seemed to run in 2 cyl...then it cleared up. So I'm thinking I might still have issues inside the tank as well, or as someone suggested, maybe my gas cap isn't venting.

Any progress?  As for your vent working it is pretty easy to tell.  After you get done riding pull it into a quiet spot and shut it off.  You should be able to hear venting action from the fill cap if you get your ear really close.  It can be especially noticeable on warmer days.  If you are still having starvation problems I would take you petcock off and disassemble it.  I had similar problems and all seemed good until I looked closely at the petcock.  They can get restrictive buildup inside the internals, much like cholesterol buildup in arteries.  I had to scrape quite a bit of old varnish out of the galleys, I never have had a problem since.  Also the main draw tube on mine was 80% clogged with varnish, I had to use a drill bit to bore the crap out.

[ajinreno]

Thanks for asking Hapsh, i wasn't planning on boring you lot with my continuing problems, especially since it no longer has anything to do with a dead battery.

I ruled out the venting problem....I had the gas starvation problem again. It always seems to happen when i've been cruising a long at high rpms. So I pulled off the freeway and opened the gas cap, no sound. Then I started it and ran it with the gas cap open and it was still running on 2 cylinders. I let it sit for about 5 minutes and then took off again and it was fine. Was on my to coach soccer...so it sat parked for about 1.5 hours. Started it up and now it only runs on 2 cylinders all the time! An associated problem I found when I was changing my fuel lines...my brand new petcock does NOT TURN OFF! Made it a bit difficult in swapping fuel lines.

I am planning on disassembling the petcock to see if it needs cleaning out. Any other suggestions? Could the petcock never turning off have anything to do with it? Does this sound more like a "spark" problem?

[hapsh]

It sounds like you definitely need to pull apart the petcock.  I had all the same symptoms.  Finally I got stuck walking the bike home.  Basically my problem was with a crudded up petcock and rust pieces in my tank.  With flow restriction in the petcock it makes it that much more prone to clogging with rust and debris.  I ended up de-rusting my tank and rebuilding my petcock, not a problem since.  There is a rubber seal that fits below the valve handle, when that goes bad it can leak gas in a way that it just bypasses the valve.  It is hard to describe so I would suggest taking it apart.  The petcock is quite simple, but there are several places that flow restrictions can occur.  Even the valve handle itself is a point of clogging, gas actually flows through the valve handle base.  I would just make sure your fuel delivery is fully operational before moving on to other things.

[TwoTired]

I looked back over this thread, and can find no mention of year model, carb style, or petcock style stated on which to refer.
All 550's are not the same in this regard, and I can see no way to give specific information to address your specific problem.

If you are still trying to isolate spark vs fuel issues, tell us which cylinders you are losing.  This can be a guide, as spark issues usually follow 1&4 or 2&3.  Whereas, fuel supply issues can follow 1&2 or 3&4 on the earlier style carbs.

[ajinreno]

It's a 76 CB550. It has Keihin carbs and Petcock p/n16950300020, at least that's what I ordered from David Silver Spares. It's the kind that mounts with 2 fasteners inside the bowl.

I believe it is cylinders 1&4 not firing, at least it was when i conducted my hand to pipe test to see which were heating up.

[hapsh]

That is the same petcock as mine.  Which nipple do you have carbs 1-2 connected to (towards the front of the tank or back)?  The nipple towards the front is the first one to get fuel because it is right off the fuel galley.  That one on mine is connected to cyls 1-2 so, 3-4 run out of gas first on mine.  The reserve delivery is quite funky on these petcocks, there is no tube, it gets fuel from around the base of the main draw tube.  It easily gets full of sediment and crud.  When you take apart the petcock valve you will see three holes behind the handle ( 3 oclock = Main, 6 oclock = Delivery to sediment bowl, 9 oclock = Reserve, 12 oclock = plugged - OFF).  When you have your valve set to ON, it allows fuel from the draw tube to come through the hole at 3 oclock and go through the handle base to the delivery hole at 6 oclock.  From there it goes down and fills the sediment bowl.  After the bowl fills, the fuel makes its way up through the filter screen to a fuel galley hole in the bowl roof.  From there it goes straight to the nipple towards the front of the petcock.  There is another hole to the right of the front nipple that allows fuel to go to the second nipple.  No fuel will flow out of the second hole unless there is back-pressure on the first nipple.  When your valve is set to Reserve, the fuel flows from around the base of the petcock draw tube through the hole at 9 oclock and goes through the handle base on towards the sediment bowl.  My petcock looked really good from the outside, but after taking it apart I found all of the galleys and flow tubes gunked with varnish, especially the holes behind the valve and the valve base itself.

[TwoTired]

It's a 76 CB550. It has Keihin carbs and Petcock p/n16950300020, at least that's what I ordered from David Silver Spares. It's the kind that mounts with 2 fasteners inside the bowl.

I believe it is cylinders 1&4 not firing, at least it was when i conducted my hand to pipe test to see which were heating up.

You must have a tank off a 74 or earlier CB550 or 500.  The two screw petcocks were used on these models.

1&4 problems sorta say its an ignition issue.  Have you set point gap and timing?

[hapsh]

1&4 problems sorta say its an ignition issue.  Have you set point gap and timing?

I miss read that, I thought he said 3&4.  1&4 does sound more like ignition.  Maybe a bad connection that opens when things warm up, or a condenser going south, they can short out when warm when they are getting old.  I am surprised that bike doesn't have a Dyna S though.

[edbikerii]

yeah, that was my first question.

1&4 problems sorta say its an ignition issue.  Have you set point gap and timing?

I miss read that, I thought he said 3&4.  1&4 does sound more like ignition.  Maybe a bad connection that opens when things warm up, or a condenser going south, they can short out when warm when they are getting old.  I am surprised that bike doesn't have a Dyna S though.

[bryanj]

The reason your petcock does not turn off is the you either did not fit the sealing washers between the retaining bolts and the petcock OR they are split and no good

[ajinreno]

I agree that it very well may be a firing problem if my hand test was correct. But might as well clean out the petcock anyway. Took it off last night and it definitely had some paint scraps in the bowl. I need to clean the mounting surface better as their is some paint flaking aroung the holes.
And bryanj, you are right, there are no sealing washers between the retaining bolts and the petcock. The new petcock didn't come with any and the old one didn't have any. I'm assuming I can go to the hardware store and get any type of rubber or crush washer???

[Philly550K1]

And bryanj, you are right, there are no sealing washers between the retaining bolts and the petcock. The new petcock didn't come with any and the old one didn't have any. I'm assuming I can go to the hardware store and get any type of rubber or crush washer???

they are fiber washers, still available from the dealer last i checked, or at lowe's, etc...

[ajinreno]

Update:
The good news, put some neoprene washers in the petcock and now it shuts off...unfortunately that is the only good news so far.
The bike only runs on 2 cyl now (2&3) as opposed to going in and out. I checked the gap on the points and made some slight adjustments. The points have white/gray spot covering the majority of the center. I have filed them with an ignition file, but they still have the white/grey centers. Both points have it. Don't have a timing light so didn't check that. Both 1&4 plugs were badly fouled and wet. I'm hoping that is normal for non-firing cylinders and not a sign of major work needed.......please tell me I'm right about that...

[TwoTired]

You can make yourself a timing light with a 12V instrument bulb (3w) two wires soldered to it, with alligator clips on the end.  Set the point gap, then clip the test light across the points connections, turn on the Key switch, and rotate the crank to the 1-4 F timing mark.  The light should come on when this occurs.  Rotate the 1-4 plate position until it does.  Not only does this set the correct timing for 1-4, it also tells you if your points are working, as crusty points won't douse the light when closed.  After the 1-4 plate timing is set correctly, repeat the procedure with the 2-3 point gap and timing plate.

If the light never lights when the points are open, then you have either a coil issue or the power to the coils is missing/faulty.

If your plugs are fouled bad enough, they won't fire.  Replace them or clean them with an abrasive blaster.

Cheers,

[ajinreno]

Thank you for such easy to follow instructions TwoTired!!!! I made the timing light and sure enough, no light comes on with 1-4 (but it does for 2-3.) At this point do you think a novice mechanic like me should take it to a mechanic to trouble shoot (I just found a guy in town who does old Honda work) or is there a simple way to trouble shoot if it's the coil or not? Or should I just replace the coil?

On a side note, when I tested 2-3, the light came on before I got to the F mark. Do I adjust it so that it comes on exactly when it hits the mark? And I'm assuming I shouldn't bother until I get the coil sorted out and get 1-4 timed correctly first.

Thanks for your help!

[ajinreno]

AAARGH!!!! Strike all that! I just did it wrong. I just got a manual in and followed the instructions there. The first time I did it I clipped the light to both sides of the points. And the light never came on for 1-4 (but it did for 2-3?!?!?) The manual said to clip one to the bolt connecting the blue wire to the point and to ground the other clip...I did that and the light goes on and off...a little early though. So I will adjust the timing and report back.