first bike---need help

[wes]

wow. great forum. just got my first bike. i fell in love with and just purchased a 78cb750. looked at several bikes, really liked this one. it started and idled great the 3 times i looked at it. when i had $$$ in hand they guy let me drive it. it rode great for a good 15 miles, so i bought it. put about 100 miles on it. while driving, started sputtering. got worse, cut off. it started back and would run with choke on...still sputterd out. had to trailer home. i filled it up with regular gas when first got it. thought problem might be with old gas in tank. emptied the tank, dropped and cleaned carb bowls,they didnt look dirty.filled tank with 93octane and added seafoam. removed plugs, one looked like carbon build up, othe 3 where black. cleaned with wire brush, charged battery. vroom...started with no problem. idle is set  at about 2000rpm... long story short... it died on me again after about 5 miles. it is sitting at bottom of hill in friends yard with battery charger on it.ive about worn my leg out on kick start. first question please... will it hurt to charge battery still connected to bike, switch off of course.#2 any thing else simple i can check.#3 how do i chose a good mechanic.#4 how much is reasonable to pay for a "tune up"? assuming thats all it needs. im no mechanic, but i have been taken advantage of by a few of them. im gonna let battery  for another 30 mins then see if i can get her home. any advise please????

[wes]

after bike sat on charge for about 30 mins, started fine and drove home. still sputterd... will bike not run if battery  isnt getting charged??

[TOOLS1]

Welcome to the forum. No the bike will not run if the battery is not getting a charge, but it sounds like you are having a fuel issue. Check the vent in the gas cap, and pull the fuel line to check flow.
As for a mechanic? I would recommend you start asking other riders in your area, for recommendations. However I would recommend, you go to the manuals section here, and download the manual, for your bike. These bikes are very easy to work on, and parts are readily available.
TOOLS

[wes]

thanks tools, that manual is nice! i saw alot of easy things to check i can do myself. im gonna post a pic of her soon. here is a pic of a batch of home brew.gonna chek battery,make sure its gettin charge. then maybe ill try to "check the carb vents" per the manual. i seen that 2 is to high for idle.

[Cabreco]

Wes
For the most part you don't have to be a mechanic to work on these bikes, just have to use common sense & care when removing parts & the right tools. The fact that you emptied the tank, dropped and cleaned carb bowls, added seafoam & removed plugs says to me you are more of a mechanic than you give yourself credit for.

The manuals are a godsend, and the people on this forum are extremely helpful with answers.
this does sound like a fuel delivery issue.  

What was the condition of the bike when you found it? Was it a daily driver, in storage, or unregistered & sitting around?

[wes]

the fella i got it from has had it since march. said he drove it a couple of times with no problems. its beautiful. very clean. he did say the gas had been in it since march. it does seem that the bike runs as long as the batery is charged. i thought the battery was only to start the bike, didnt realize it wouldnt run without it. learning every day. if the battery has no charge, you can kick all day. want to see if charging system is working. after tank clean and seafoam, she did backfire a lil while running. gonna ppull plugs again, ive been readin on here. sounds like you can tell alot from the apperance of the plugs. it sucks i have to go to work and cant spend more time with this bike. the ole lady wont let me bring it into the livin room.

[wes]

have not checked the fuel line for actual "flow". didnt know there is vent in tank cap. makes good sense though.

[wes]

ohh yeah, thanls cabrico and tools for interest in getting my ride rollin! i do alot of volunter work at local soup kitchen/homeless shelter. maybe your advice is karma coming back.

[cheesehead]

As for the charging issue, fire it up and make sure it's at 2000+ RPMs and put a volt meter/multimeter on the battery and see how many volts you're getting. You should be getting approx. 13.5-14.5 volts. If it's in the 12 volt range, you definitely aren't charging.

If it's NOT charging, it can be one or more of 4 things, the battery, stator, rotor, or regulator/rectifier. To check your stator, follow the fat wire that comes out of your stator cover up until it plugs into the wire that comes from your R/R and unplug it. On the stator end you should see about 6 holes with 5 wires in them, 3 yellow, one black, and one white. Set your volt meter to test OHMs. Stick your red and black lead on your meter in ALL combinations of the YELLOW wires (4 total combinations, I think). I read that it should read .5-.6 OHMs in each combination, but in reality it may read .8-.9, mine all read .9 when I checked it, which verified that my stator was good. If that's good, remove the stator cover and you will see the rotor staring at you. On the rotor are 2 copper rings, one large and one smaller. Again set your meter to OHMs and stick one lead on each ring, then reverse it and check the leads on the opposite rings (All of this with the key removed, by the way). It should read somewhere between 4-6 OHms, I think the 4.2 range is the norm. Mine read 1.1 when I tested it, verifying that my rotor was in fact my problem. I had my battery checked at autozone and they said it was still good, but old, so I bought a new one anyway. If your stator, rotor, and battery are all good, the only thing left would be the R/R, so it is more than likely bad. Unfortunately, I'm not 100% sure how to check it so I'm not going to give you bad info on it. But if all else is good, it has to be the problem, assuming all terminal/battery connections/ground wires are good.

You can refer to my link here for a couple pictures and maybe a little info.
http://honda-cb750-s.456789.n3.nabble.com/1981-CB750k-not-charging-the-battery-td3144722.html

Brian

[wes]

cheesy..thanks for the info. it appears that my battery is getting charge. it reads 11.75engine off. and increases as motor excelerates. its getting a small backfire, delayed ignition noise frome the left side. when i start it cold, i can feel with hand that this pipe is slowest to warm up. the second pipe from left. the first advise i got on here was that it sounded like a fuel problem. thats where im at. gonna try to post some pics tonight. ride on bigbluecheese!

[Cabreco]

Wes
When I picked up Fiona, the ouside pipe on the left side would always be significantly cooler than the rest.
After a ride, I could touch that pipe for a few seconds, as opposed to the other 3 which where IMPOSSIBLE to touch. First I cleaned the plugs & is got warmer but still not as hot as the rest.  They didn't look that bad but I decided to change all the plugs anyway (they were cheap) Now all 4 pipe are untouchable.

Just figured I would share that bit, especially that for under $15 it may be your cure as well, & if not it never hurst to have fresh firesticks.  

[wes]

did not get the pop/back fire before seafoam and the 93octane. hmmm? raod around the block. still a thrill but deff needs some tune.

[Lucky 1]

Some older Hondas CANNOT be hooked to a charger until you disconnect the battery from the system.

Check the workshop manual.
It has to do with how rectfiers were made back then.

I used to work at a Honda  Dealer during that time as a mechanic.

Your problem just sounds like clogged idle jets from sitting around with old gas.
The only way to unclog them is to remove the carbs and clean the idle jets.
You will need some help. Not for a beginner.

[Lucky 1]

Anytime something wont run bystanders always SAY,"Sounds like its not getting fuel"

Problem is WHAT is not getting fuel, and what proof is there that that is the problem? Means nothing.

[Cabreco]

donald branscom wrote

Some older Hondas CANNOT be hooked to a charger until you disconnect the battery from the system.
Check the workshop manual. It has to do with how rectfiers were made back then.

I can verify that 1st hand for the 1972 models.
When I was a kid I fricasseed the rectifier in my Chopper by connecting it to a battery charger while the battery was connected.

[wes]

ouch.. i did charge battery once while on bike. now i think, how stupid??? old bike...could have cooked something. it has started and ran several times since then. just still feels outta synch.

[TOOLS1]

I do not think a trickle charger/tender would hurt.
TOOLS

[Cabreco]

TOOLS1 wrote

I do not think a trickle charger/tender would hurt.
TOOLS

No I used a Sears 10/2/50 Amp charger.

[wes]

the charger was set on the 2amp trickle charge. im thinkn this battery has to do. maybe the guy i got it from kept it on a tender or somethin b4 i got there. it was an old sears charger matter o fact. battery just read 11'43amps and would hardly turn motor over. is now on neighbors charger. ill bet she will fire off and run while battery has fresh charge. still gonna put fresh plugs in next
i have not yet named this bike.

[TOOLS1]

It's black, and blue, so call it Contusion. As, for plugs. Spend a little extra, and get Iridium plugs. Worth every penny.
TOOLS