« previous next »
Pages: [1]   Go Down

Author Topic: CB750 Ignition problem, looking for advice  (Read 1288 times)

0 Members and 1 Guest are viewing this topic.

Offline gold72

  • Full Member
  • *
  • Posts: 90
CB750 Ignition problem, looking for advice
« on: June 06, 2010, 02:19:22 PM »
I purchased a 1978 CB750K about a month ago.  The bike was running pretty well when I first got it but in the last few weeks the bike has been stalling out a lot and will just die will the engine is running.  This can happen at low idle (1000 -1500 rpm) and at high idle.  I thought my battery was the problem as I would charge the battery up over 12 volts before taking it out, and whenever I was having an issue if I checked it afterwards the battery was down to 11.3 - 11.5 volts.  I replaced the battery the other day but the issue still seems to persist.

My new battery is maintaining its charge, it was at 13 volts yesterday when I checked it but the bike was still stalling out.  The bike is usually pretty easy to start but when I go to put it in gear about half the time it will stall.  I'm thinking that I may need to replace my ignition coils. 

I'm currently running a Dyna electronic ignition, so I was thinking about buying a set of Dyna ignition coils and leads.

Has anyone experienced a similar issue, or can recommend some things to troubleshoot?

Cheers

Logged
1972 cb500

Offline gold72

  • Full Member
  • *
  • Posts: 90
Re: CB750 Ignition problem, looking for advice
« Reply #1 on: June 06, 2010, 02:20:17 PM »
I forgot to mention I have tested all my plugs and leads and they are all getting a spark.
Logged
1972 cb500

Offline OldSchool_IsCool

  • Really feeling like an
  • Old Timer
  • ******
  • Posts: 4,350
  • WARNING: Objects in mirror appear to be LOSING!
Re: CB750 Ignition problem, looking for advice
« Reply #2 on: June 06, 2010, 02:46:06 PM »
Does the voltage go up when you rev your engine above 3K?  Does the voltage top out around 13.5v?
Logged
Can I have a motorcycle when I get old enough?
If you take care of it.
What do you have to do?
Lot’s of things. You’ve been watching me.
Will you show me all of them?
Sure.
Is it hard?
Not if you have the right attitudes. It’s having the right attitudes that’s hard.

Offline Alan F.

  • We remember the Night Rider, and we know who you are.
  • Really Old Timer ...
  • *******
  • Posts: 7,347
Re: CB750 Ignition problem, looking for advice
« Reply #3 on: June 06, 2010, 07:35:56 PM »
What shape is the rest of your electrical system in? Cleaning any corrosion and dabbing some dielectric grease in each and every connector is a required procedure on any old bike. You may have an intermittent electrical issue, but then again you may have a fuel system issue, or since the bike stalls when you put it in gear, I wonder if the clutch is sticking?

Maybe someone else can chime in on some of these thoughts, but we're probably going to need more info about the condition of each of these areas of your bike.  How's the inside of your fuel tank? is the petcock screen clean? Since you haven't had the bike long it could be that you have a combination of issues causing this one symptom.

Please tell us more and pictures speak volumes so post them if you need to help explain anything. 

You may want to re-title this thread along the lines of a stalling problem, it could get more attention from the better minds.
Good luck.
-Alan
Logged
Pages: [1]   Go Up
« previous next »