CB750 Unknown problems

[tdielmann]

Hello everyone, new to using forums/blogs and such so please forgive any formalities I may overlook. I'm currently living near downtown Boston so access to tools and parts is limited. Purchased a 73 CB750 3 Months ago, running fine and from my limited knowledge strong. Its been sitting for periods of time next to the apartment of up to 4 days before i would be able to ride it due to work etc. Until recently, about 3 weeks ago the bike would not start and simultaneously the electric starter began making a buzzing noise rather than kicking the engine. So after 30 minutes of trying to kick start I gave up, banking on a dead battery. Got a battery tender and a few days later gave everything a try again. starter still buzzed and the bike wouldn't kick. checked and double checked fuel was getting in and key was turned etc. (anything stupid I may miss). then the next day the bike finally kicked over and ran. No idea why. So I rode it around and everything was good, aside from the bike running a bit rough (probably should clean/tune the carbs) and the oil was white (from what i understand the bike sitting in a rainstorm or two may have done that so i'm going to change the oil and filter as soon as the bike runs)...on the subject of oil there is also a leak somewhere possibly under the battery on the engine or maybe below that (just giving as much info as possible because I have read miracles on sites like this from guys who know what they are doing). SO while the bike was running, took it to get inspected, ended up having to leave it at the shop bc I got a flat on the way there -_- now 4 days later, go to pick the bike up and it wont start, guy doing the work wasn't to friendly or willing to help as this establishment was a weekend thing for him. ended up pushing the thing back...charged the bike a few days...and now for the past two days i'm back to where I was before, starter buzzing and unable to kick start. Any and all insight appreciated. I am willing to do any and all work just need advice on where to get started and what to check first. Thank you, and I'm sorry for such a long post.

[Black 750K8]

Those sohc bikes like a good strong battery. I would start there put it on the charger but unhook it from the bike first. Leave it on all night next morning take the charger off leave the battery unhooked wait at least two or three hours then check to see what the battery voltage is it MUST be 12.60 vdc or higher. Tell us what type and how old your battery is. If it is the type that you can add water to it then do that first before charging use distilled water only and top it off. While it is charging clean the connections. report back with your results. If it sits in the rain clean connections are a must.

[shinyribs]

Battery tenders are great for maintaining a battery,but they don't have the guts to actually charge one.

And yes, these bikes really do need a healthy battery. I've found that ,on my own bikes, if the battery is too weak to crank the engine with the starter then it is too weak to light off the ignition as well.


Charge her up and then keep using your battery tender. You should be good after that.

Good luck and let us know what you find! And welcome to the forum.

[TOOLS1]

At least your dog did not die. Damn you have some bad luck. However you are at the right place, as we'll do whatever we can to help. First off download the factory service manual from the home page here (it's free.) Second, is your battery taking a full charge? Take an ohm meter, set for DC voltage, and test it. It should have at least 12.5 volts. Third, check all your connections. Even the back side of the fuse block. They are notorious for coming loose at the soldered connections. This should keep you busy for a little while.
TOOLS  

[tdielmann]

So I went and bought a multimeter today, got a reading of about 10.80 so I pulled the battery and saw the water level was low. Filled it and have it on the trickle charger now. Thanks so much for the quick responses, this is an amazing system.

On Jul 17, 2013, at 2:01 AM, "TOOLS1 [via Honda CB750'S]" <[hidden email]> wrote:

At least your dog did not die. Damn you have some bad luck. However you are at the right place, as we'll do whatever we can to help. First off download the factory service manual from the home page here (it's free.) Second, is your battery taking a full charge? Take an ohm meter, set for DC voltage, and test it. It should have at least 12.5 volts. Third, check all your connections. Even the back side of the fuse block. They are notorious for coming loose at the soldered connections. This should keep you busy for a little while.
TOOLS  

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/CB750-Unknown-problems-tp4043606p4043620.html

To unsubscribe from CB750 Unknown problems, click here.
NAML

[sgtslag]

A trickle charger will, eventually, fully charge a battery, even a new one being filled, and charged, for the very first time -- it will just take a long while...  The Battery Tender Jr. smart charger pumps out only 0.75 Amps, so it will take quite a while.  For a new M/C battery, the maximum charge rate should be 1-2 Amps, no more, to avoid damaging the plates within, from excessive charging current.  The best advice, however, is to follow the manufacturers' instructions, to the letter.  After that, no more than 1-2 Amps charging rate, to avoid damaging your battery.

Hooking up to a smart, trickle charger, after each ride, religiously, is a very good idea.  Doing so can double the life of your battery, if it is a flooded cell type; it can help Gel Cells, and AGM types as well, but the benefits are not as dramatic.  Cheers!

[Black 750K8]

from shinyribs
 Battery tenders are great for maintaining a battery,but they don't have the guts to actually charge one.

 I agree in part if the battery is drawn down to low 7 or 8 volts then bring it up with a bigger charger when you get it up to 10 to 11 volts then use the tender. The state of the battery has a lot to do with how you charge it for sure. I think they call it a tender for a reason. That is why I use maintainers and have five different types. If you want a primer on batteries read all the stuff here just to get you started.

http://www.batterystuff.com/kb/ 

[Lucky 1]

IF the battery was 10 volts you need to buy a new battery.

Even if a battery is very low it should still be 12 volts minimum.

Each cell is 2.3-2.7 volts when fully charged. What gets low is the amperage.