« previous next »
Pages: [1]   Go Down

Author Topic: no power  (Read 1763 times)

0 Members and 1 Guest are viewing this topic.

keener

  • Guest
no power
« on: May 26, 2008, 10:44:19 AM »
I have a 77 CB550K and just got it running again after a small electrical mishap and When I take of it is very slow to gain speed and has no power when shifting to second. The idle is ok and it sounds fine reving it up. The RPMs go up when driving but not the speed or power. Any advice would be great!!!... >:( I just want to get back on the road.

Chris
Logged

Offline DammitDan

  • Prodigal Son
  • Master
  • *****
  • Posts: 2,470
  • It lives!
Re: no power
« Reply #1 on: May 26, 2008, 10:46:54 AM »
Sounds like you're not hitting all 4 cylinders...  Are all 4 pipes hot?
Logged
CB750K4

keener

  • Guest
Re: no power
« Reply #2 on: May 26, 2008, 10:50:59 AM »
wow, 1 and 4 are much hotter that must be it. is it a common thing. This is my first 4cyl...??
Logged

Offline DammitDan

  • Prodigal Son
  • Master
  • *****
  • Posts: 2,470
  • It lives!
Re: no power
« Reply #3 on: May 26, 2008, 10:54:56 AM »
No, 4 cylinder bikes normally run on 4 cylinders so running on less isn't common  ;D  ;D

But now you get to start the troubleshooting process.  If 2 and 3 are only warm and 1 and 4 are hot, there could be several things going on.  First off check the spark on the #2 and #3 cylinders.  Those two cylinders run off the same coil (and 1 and 4 run off the other coil).
Logged
CB750K4

Offline bozo4onion

  • Hot Shot
  • ***
  • Posts: 368
Re: no power
« Reply #4 on: May 26, 2008, 10:59:31 AM »
When my 550F did this exact thing it was 1 of the 2 condensers had failed. Good luck.
Logged

keener

  • Guest
Re: no power
« Reply #5 on: May 26, 2008, 11:16:38 AM »
so 2 and 3 are not firing   :(
Logged

Offline OldSchool_IsCool

  • Really feeling like an
  • Old Timer
  • ******
  • Posts: 4,350
  • WARNING: Objects in mirror appear to be LOSING!
Re: no power
« Reply #6 on: May 26, 2008, 11:33:01 AM »
Sounds like it.  As mentioned, 2&3 plugs fire off the same coil which is triggered from the right-hand points.  Start with the plugs.  Pull #2&3.  Do they look good? (slightly tan in color) or are they black and sooty, black and oily,or maybe bright white with a speckled insulator?  Do they small of gas?

Hold the metal part of the plug against the fins, plug wire on.  Do you get a spark when you crank the engine?

Yes - swap the plugs with 1&4.  Do the 2-3 pipes got hot while 1-4 are cold?  if yes, bad plugs, replace them

No Spark?  Time to look at the points.  Let us know if you get here.
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.

keener

  • Guest
Re: no power
« Reply #7 on: May 26, 2008, 11:45:41 AM »
all plugs are sparking out of the 1 and 4 plug wires. The Plugs are NGK DR7Es they are not in the best shape I will replace them tomorrow but the 2-3 wires are not firing.
Logged

Offline OldSchool_IsCool

  • Really feeling like an
  • Old Timer
  • ******
  • Posts: 4,350
  • WARNING: Objects in mirror appear to be LOSING!
Re: no power
« Reply #8 on: May 26, 2008, 11:50:48 AM »
You have the wrong plugs.  Your plug caps have resistance, your plugs shouldn't.  Check your caps with an ohm meter, should be around 5k to 6k ohms.

When you buy new plugs, get NGK D7EA and gap them to .024 in.   
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.

keener

  • Guest
Re: no power
« Reply #9 on: May 26, 2008, 11:54:23 AM »
but if they were the wrong plugs shouldn't None of them fire. Could it be that the resistance just differs a small amount but just enough to stop it from firing??
Logged

Offline OldSchool_IsCool

  • Really feeling like an
  • Old Timer
  • ******
  • Posts: 4,350
  • WARNING: Objects in mirror appear to be LOSING!
Re: no power
« Reply #10 on: May 26, 2008, 12:13:35 PM »
They would probably fire just fine in the open air.  Question is, what happens under pressure?  Get the correct plugs, correctly gapped, and we'll see if it has an effect on the problems you are having.

Also, do you have details on the electrical mishap you mentioned?  If it took out your alternator, regulator, rectifier or battery, you may be seeing undervolt conditions causing her to not start.  Does your starter spin at a reasonable speed or is it labored?  Have you tried kick starting?  If you have a battery tender, hook it up over night while you wait for new sparks.

A little carb cleaner into the intakes of the carbs will act as starting fluid which might give her the pop or three that she needs to fire up.
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.

keener

  • Guest
Re: no power
« Reply #11 on: May 26, 2008, 12:22:21 PM »
I got a new battery from faulty information and the leads were backwards and it cooked some insulation. I re-insulated the burnt wires. The wires that cooked were into the rectifier but it looks good still. There was a fuse from the last owner that was not the correct amperage and probably saved me. Ill get the new plugs and gap them and finish it up tomorrow. Thanks a lot for the help and I hope to hear from you tomorrow again.
Logged

Offline OldSchool_IsCool

  • Really feeling like an
  • Old Timer
  • ******
  • Posts: 4,350
  • WARNING: Objects in mirror appear to be LOSING!
Re: no power
« Reply #12 on: May 26, 2008, 12:34:00 PM »
Yea! Battery backwards can be pretty harsh on components!  It would be worth your time to check how well she charges the battery back up, just to make sure nothing but wires were fried. 

When we get her running well, check battery volts with bike off, at idle (1000 - 1500 RPM) at 3000 RMP and at 5000 RPM.  Report the numbers back.
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 Gordon

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 12,114
  • 750K1, 550K2
Re: no power
« Reply #13 on: May 26, 2008, 01:34:18 PM »
Quote from: keener on May 26, 2008, 12:22:21 PM
I got a new battery from faulty information and the leads were backwards and it cooked some insulation. I re-insulated the burnt wires. The wires that cooked were into the rectifier but it looks good still. There was a fuse from the last owner that was not the correct amperage and probably saved me. Ill get the new plugs and gap them and finish it up tomorrow. Thanks a lot for the help and I hope to hear from you tomorrow again.

Chances are you fried the rectifier.  It doesn't have to look bad to be toast, and it only takes a split second of reverse polarity to kill it. 
Logged

keener

  • Guest
Re: no power
« Reply #14 on: May 28, 2008, 06:38:33 AM »
well the new plugs still aren't firing on 2 and 3. The plug caps all have a resistance of about 5 ohms. 1 and 4 are going fine. Ill check the rectifier, whats next for me?
Logged

keener

  • Guest
Re: no power
« Reply #15 on: May 28, 2008, 07:01:15 AM »
well tested the rectifier and it looks to be fried as per FAQ section. Now I have to start the search for a new one... ???

Why does 2 cylinders still work? The diode arrangement??
« Last Edit: May 28, 2008, 07:03:57 AM by keener »
Logged

Offline Gordon

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 12,114
  • 750K1, 550K2
Re: no power
« Reply #16 on: May 28, 2008, 07:46:20 AM »
Quote from: keener on May 28, 2008, 07:01:15 AM
well tested the rectifier and it looks to be fried as per FAQ section. Now I have to start the search for a new one... ???

Why does 2 cylinders still work? The diode arrangement??

The bad rectifier is not causing your two-cylinder running problem.  The bike will run fine with no rectifier at all, it just won't charge the battery. 

Take a look at http://www.oregonmotorcycleparts.com/Products.html for a replacement rectifier.  I have one of his on my 550 and 360.  There are also instructions in a couple of different places on this forum on how to make your own rectifier pretty easily. 
Logged

keener

  • Guest
Re: no power
« Reply #17 on: May 28, 2008, 08:02:36 AM »
so im just going to need to get the R2-55a rectifier for 1969~1978
SOHC in-line four cylinder Honda's? wow, seems easy enough. nice site
Logged

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,805
Re: no power
« Reply #18 on: May 28, 2008, 11:25:48 AM »
Quote from: keener on May 28, 2008, 07:01:15 AM
Why does 2 cylinders still work?

Did you check the points settings/connections?
Logged
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

keener

  • Guest
Re: no power
« Reply #19 on: May 30, 2008, 04:46:09 AM »
No I haven't yet but I'm checking those and the condensers tomorrow.
Logged
Pages: [1]   Go Up
« previous next »