Topic: What did I do wrong???

[JHansen]

Well, here is another problem, and I'm not sure where to begin...

Came home tonight with my newly purchased timing light and carb synch with the intentions of double checking my timing before synching carbs. Got bike (cb400) started and warmed up, checked my gap clearance, (.358mm) hooked up my light (coupler on #1 plug wire) and found that the 1.4 timing was advanced (I think!) at 1200 rpm. "F" marking was to the left of the static mark, and no matter how much I played, I couldn't get it to even line up with the static mark, let alone get the mark to go to the right of it. I pulled of the points plate and examined the advance unit and found that it all moved freely, no binding at all. Checked timing for 2.3 plugs, and they were spot on. This went on and on for about 2 hours, running the motor, shutting down to make adjustments, restart, check and so on. Ran a fan on motor to keep things cool.

I used the kick starter mostly, but my batt now shows about 6 volts, according to my meter. No cranking power what so ever, and I have no spark on at least the number 4 plug. (only one I checked.) The last three times I was playing with the timing, the bike just died, and wouldn't restart for about 20 mins each time. No it's not starting at all. Would a dead batt really keep it from not firing up if I used the kicker? With the key on, power drops from 6 to 3 volts, but that power is getting to the points plate. Thought about swapping a battery form another bike in the garage, but may just go buy another tomorrow.

Thoughts on how to get her fired up again? Where do I start? Any questions I can answer? I may have left out a missing detail or something, HELP! 

Thanks! John

[78_SaltLick]

yeah a bad battery will stop it from starting even with the kicker.

[comcrx]

yeah, and I've noticed that on my bike that prolonged idleing doesn't provide enough power for lights, ignition, and recharging the battery. I usually try to make the last couple of minutes of my rides above 2500 rpm to make sure the battery has at least enough charge for a start the next morning

that may not be completely accurate info, but it works for me

andy

[JHansen]

I agree with you guys, but will a dying battery kill a running (idling) motor once the volts fall low enough?

I did have it on a battery tender between runs after I checked and found low voltage, but it was only for 20 mins or so each time, not enought to build up much charge, and now that battery won't take a charge at all.

[Dusthawk]

Greetings,

Yes, definitely, a dying batt can kill an engine. All the demands on the batt already weakened can toast a batt.

A few ideas that I've put into practice might be of use.

An automatic trickle charger plugged in over night helped me out tons. I have easy access to my batt so I have spring clamps, you can also make a harness with ring terminals and a small connecter easily hidden behind the side cover.

When I am working on timing and do a lot of startups, I turn off the headlight switch(custom application) to conserve power, and in between running, I connect the trickle charger, for that extra little bit it adds.

I bought the chager at my local auto parts for 20 bucks.

I hope this helps just a little bit or more,

Peace and Long Rides,

Jeff

[JHansen]

Cool, I'm either buying a new battery or seeing if this one will charge up (not likely).

Now, any thoughts on why the timing in 1.4 plugs won't come in line and why the marks for my 2.3 line up perfectly?

[Dusthawk]

Now, any thoughts on why the timing in 1.4 plugs won't come in line and why the marks for my 2.3 line up perfectly?

Well, seems to me I heard about something like this, maybe the condenser? on that set of points? For some reason, that ideas tickling my noggin.

Good Luck,

Jeff

[Rushoid]

I read somewhere that the battery doesn't charge with the engine at 1700 rpm or below. When I was trying to get mine running I had to keep putting the charger on it. I thought there was something wrong with the charging system. But now that I'm riding it it always has juice.
I think I also read that higher mileage engines run better slightly advanced. I know mine does. I don't know if this is really true though. I'm just a newbie

[GroovieGhoulie]

These bikes will NOT charge the battery below 2000 RPM.  Period.  They use the battery to feed the electrical system below 2000.  Excessive idling is draining the battery most certainly.  Charge it up, and try and reduce the load by pulling the headlamp and taillamp fuses while dickering with it in the garage.  That'll help.  Then, take the advice of the others and buy a charger to pump it up.

[texian_biker]

     I'm new to this post and everyone on this post probably already knows this but you can static time your motor old school style with a piece of cellophane to get things close enough to start your motor and make minor adjustments with timing lite.
     Find a friend that smokes and get the cellophane off his/her cigarette pack.
     Set your point gap on both sets.
     Rotate engine to proper index mark and loosen the big points plate.  insert cellophane between points and rotate plate till points grab cellophane.
     gently pull on cellophane and rotate plate clockwise till you feel cellophane give.  Lock plate down, you're timed on this set.
     Rotate engine to index and repeat with small points plate.  If you can't get them timed correctly adjust point gap on both point sets till you get timing set correctly.
     Start engine and apply timing lite.
     If condensor is bad you'll see excessive sparking on points.
     I engine won't start it's probable that points aren't opening.
     BTW...it sounds like your battery is toast
     
     

[78_SaltLick]

my bike died and i came to a depressing stop at a stopsign because of a bad battery so it def happens. I was noodling around town, and not really getting my rpms up enough to recharge the failing battery. I had been working on it also and starting it up, and starting it up, and starting it up, i had no idea at that time that this was all just draining the battery.  i was lucky enough to be right next to a battery place when it died, so i rolled it over and they hooked it up to a charger to see what the voltage was. It was low and would not hold a charge, so in my case there was a dried up cell.  We wondered if it wasnt the charging system at first, so he put a new battery in it, and hooked some sort of regulator up to it then we revved the engine up and watched the voltage go up on the meter, which meant the charging system was working. I put in a new battery and havent had a problem since then. Also helps to buy a battery tender, i hook that up once a week to get the battery fully charged again, im not even sure that is necessary if your charging system is working, i just do it to make myself feel better......

[TwoTired]

A spark gap needs a minimum voltage for an arc to jump the gap.  On the SOHC4, the spark voltage is proportionally related to the battery voltage. When the battery voltage drops below about 8 V there isn't enough voltage to jump the spark gap.  Without ignition, the engine won't run.

The stock battery has about a 4 amp hour rating, meaning it will provide about 4 amps for an hour before the voltage drops to 9 v or so.  Let's say its 48 watt hours.  48 watthour = 172 800 joules of stored energy.
 
Electric starter draws 150 amps;  or 1800 wattseconds = 1800 joules  or  96 seconds = dead battery (from full charge)
A 50W Headlight draws about 4.2 amps;  or 50.4 wattseconds = 50.4 joules   or  57 minutes = dead battery (from full charge)
1 - 5 ohm ignition coil draws 2.4 amps
Alternator draws about 1.7 Amps to make a magnetic field.
other lighting - more Amps

On a stock bike, the alternator doesn't make enough power to overcome the system loads and produce enough extra juice to charge the battery until the alternator is spun 1800 - 2200 RPM or above.

Deep discharging motorcycle batteries usually shortens their productive life.  Successful recovery is on a case by case basis.  Some can come back, some can't.

Hope this helps.

[Orcinus]

Just my two cents, but if you're going to be testing in a static location, you might want to disconnect (and pull) your batt and hook up something car or truck sized.  It works fine and will give you a little more to fall back on while testing and timing.  You could be trickle charging your bike batt while your tinkering too.   

[golden_child]

So, I am having the same problem with my bike, 72 CB750. The first month I had it 9april 2006) the the battery was lasting. I took it for a ride a week and a half ago and it died at a stop light by my house (I was lucky I was as close as I was). I charged the Batt over night and took it out the next day and it drained after an hour of riding. Lucky for me I felt the change in the engine and turned off the headlight and that gave me enough juice to get home. I could definiutely feel a change in the engine when I turned off the light. So, when I got back home I cut it off and let it sit for a minute or 2. I then kicked the engine to get it started again (no lights on) gave it a few revs the turned in the headlight and the engine stalled and died.

So, I've noticed that my headlight is draining my battery even when I am riding my bike (above 3k rpm). Can someone tell me where to start my trouble shooting? Should I have the batt checked first? It's a now a 2 month old wal-mart battery aka Never-Start, by a local motorcycle dealer.

a little history:
I bought the bike from I guy up in connecticut (over ebay). He has actually been very helpful so I have no reason to believe he was unloading a junk bike to me. The CB750 had been sitting in storage since Nov 2005 and sold to me April 2006. He said the only thing I would need is a new battery and an oil change. According to him it would get a tune up every year and a new battery. So, when I got the bike back home I purchased a new battery at Wal-Mart and filled it up. I did not do the initial charge, (a friend who was helping me said I would not have to worry about it).

In the mean time I was getting ready to pull the old battery out and figured "Hell, I check to see if the old battery still has a charge" so I flicked the lights and turn signals and they worked, to my surprise, I thoght the battery would be drained/dead from sittning. The only thing electrical that didn't was the horn (i just needed a new one). I didn't try to start the bike. So I changed the battery anyway and it worked well for about a month.

I am a new rider, so the first month or so I kept the revs kinda low and just putterd around the neighborhood. So a week and a half ago  I start feeling a little more confident in my riding. I wake up early on Saturday morning to beat any traffic in the area. I get to the stop light 250 yards away, down hill (a BIG hill) and then putter, putter, putter, silence (luckily at a stop light). I shut off all the electrics kick, kick, kick, wait 2mins, Kick,  Kick Vroooom. Clutch, first, a little gas, a little off the clutch, Dead again. Kick kick. nothing. let it sit and tried again and nothing. I left it there for a few hours and came back and nothing happened (I would have pushed it home but like I mentioned before it's a BIG hill). It just wouldn't start. Then I noticed that when I would try to sart the bike w/ the headlight on the the idiot lights were barley visible. So, I ficked to light on and off to see how much the difference was in brightness. It would go between somewhat visible and barely visible. So I took the batt out gave it a quick charge came back reinstalled it and the bike started right away. I got it home as quick as I could and charged the battery.

The next day, Feeling confident that everything was okay I took it out the next afternoon. Everything seemed fine lights on, signals working, horn beeping, me riding through Rock Creek Park. All of the sudden i could feel a change in the way the engine reacted to throttling and and changes in idle at stops. At stops I would give more throttle to keep the idle from dipping to low. At acceleration, if i would turn the thottle quickly it would putter a little then it would start to pick up, If i did it slowly it would get up fine. Next I turned the lights off and turned the throttle quickly and it was fine. So, I tried it with the light on again and the putter came back. I got a block from my house, off throttle, clutch in, down to second, slowly release clutch, dead to a rolling stop. I swear I didn't stall it. It felt like the bike just died. It was not violent like a, I don't know how to use a clutch, stall. Everything just died. So, I turned the headight off gave it a kick and it started. I went one block, headlight off at dusk and parked it in front of my house safely. Just to check it I started it up then turned on the headlight and the bike died.

any Ideas on where to start? I have the clymers manual and can't figure on a starting point. I would like to fix it myself if possible. but if I have to take it to a shop, then I will.           

I have also looked and posted the same info on this thread as well. After reading it, it sounded like I had a similar problem

http://www.sohc4.us/forums/index.php?topic=5613.0


 

[DaveInTexas]

Does this problem (engine reliance on battery power) depend on whether you have points or electronic ignition?  Or do both systems have the same issues?

I thought the alternator should provide enough juice to keep the coils powered up, and even if you remove the battery from the system (like cars of that era), the engine should continue to run.

[cb650]

Didnt a few members find that the slots in the plate needed to be elongated? 




                    Terry

[TwoTired]

Does this problem (engine reliance on battery power) depend on whether you have points or electronic ignition?  Or do both systems have the same issues?

More or less, yes.  There are different types of electronic ignition.  But, the spark plugs are going to need a minimum power level to fire in either case.  Electonic ignitions and high output coils allow the use of larger spark plug gaps.  These increased gaps do require more power to spark.

I thought the alternator should provide enough juice to keep the coils powered up, and even if you remove the battery from the system (like cars of that era), the engine should continue to run.

You are mistaken.
Auto alternators spin the alternator through pulley ratios fast enough so that they provide power at engine idle speeds.  Also, they mostly don't care if they use 5-7 HP to drive the alternator.  And, they don't run the crankshafts very much around the 8K plus RPM.  Auto alternators routinely provide 30 Amps and many provide much more.  Most of this is available at engine idle speeds by use of pulley size ratios.

Honda chose a design that would survive high RPM, not rob excessive power from the rear wheel, and spin with the crankshaft to minimize weight and mechanical complexity of other coupling methods.  These put out 13-18 amps peak output, depending on model, but significantly less at idle speeds.  In fact, at idle the alternator puts out less power than the bike consumes, and the battery drains.

If you keep the Honda engine and alternator RPM high enough (2500 or above for example), you can disconnect the battery and the alternator will provide enough power to self excite and run the electical load of the bike, including coils.

It is not recommend you actually do remove the battery in either the bike or the car, BTW. As the battery also absorbs voltage and current spikes that can damage the rectifier diodes, and other electronic devices wired into the system buss, if so equiped.

Cheers,

[csendker]

If you get a trickle charger, get a good one.  I bought a cheepie with a quick disconnect, permanent harness.  Then I diligently plugged it in every night.  That's OK I guess when I ride every day, but when it rains for days on end I was just cooking my battery to death.  The good ones will automatically adjust the voltage based on the battery charge and not overcook your nice, new battery.

A good one for example --> http://www.yuasabatteries.com/chargers.asp

Which can be had for less than $30 at Dennis Kirk --> http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=&store=Main&catId=412&productId=p28922&leafCatId=41202&mmyId=