Author Topic: CB400f - replacing points caused 2-3 to stop firing  (Read 6774 times)

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lohebohi

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CB400f - replacing points caused 2-3 to stop firing
« on: August 01, 2005, 05:36:27 AM »
My 75 CB400f was running poorly.  It was having a hard time revving past 5500 RPMs. 

Spark Plugs:

So I got new NKG spark plugs and a set of Honda brand points.  The plugs went in fine.  I need to buy an 18mm deep socket to tighen the spark plugs in the future.  The manual says get them finger tight then use the wrench to tighten them an extra quarter turn.  I would trust those instructions if the bike was new, but I do not because i don't think I can get them as finger tight as the manual intended with those directions.  Anyone know a good torque measurements so I can use my handy dandy new inch-pound torque wrench?


Points:
The points were pretty easy to do.  The only problem I had was on the 2-3 (R) side, the points mount to a plate that can also rotate.  I loosened this plate and forgot where it was aligned.  The manual did not really say anything about aligning the plate to anything.  I noticed when I was adjusting the point gap on the 2-3 side, moving that plate back and forth did not seem to change the point gap.  Why would this plate have an adjustment?


Fire it back up:
When I put everything back together, I was not getting spark at cylinder 2 or 3.  I tried to test continuity across both sets of points.  I just did not know how.  The Clymer manual says to rotate the special nut in the center of the breaker assembly to 1-4 and put a test light on the wire that connects to the actual point breaker for 1-4.  I did this and it did not light up like I expected (as the book indicated it would).  I even rotated the special nut all the way just in case I was understanding the book wrong.  1-4 are the cylinders that made the bike run with enough power to go down my alley.  The test light did not come on for 2-3 either (but they were not working).

My next step:
Maybe I had a pre-existing problem with a bad lead to a coil.  I am not sure how to check the coil packs.  Any ideas on how to test the coil?  Or any other suggestions on why 2-3 might not be firing?  Maybe that plate for 2-3 does something.

I will also buy a dwell meter soon just so I can tell my grandkids I adjusted points with a dwell meter.



lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #1 on: August 01, 2005, 06:52:41 AM »
I am just going to tow it to the shop.  I am at the breaking point.  Honestly, I wish I had decided to buy a newer bike.  For some reason I am unable to learn this lesson.  Sure I could get it running right, but for how long.

the faq helped me none.  I'll try the Clymer again.

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #2 on: August 01, 2005, 04:08:56 PM »
I did NOT change the condensor.  I got lazy.  There is no reason to suspect it would fail because I changed the points.  I had 2-3 firing before.  I just swapped the coil from a parts bike.  Nothing.

I am getting power at the coil via the shared wire.  I figured out how to get the test light to light up when the point contact is closed on breaker 1-4.  No test light illumination at the breaker for 2-3. 

According to the factory wiring diagram, the wire goes straight from the coil to the breaker with a a plug connector in between.  The yellow wire had continuity from the coil down to the point breaker.

It turned out the 2-3 condensor was failed.  It was probably begining to fail when I first got the bike running and caused the bike to have a hard time revving past 5000 RPMs.  After I changed the points, the condensor did not function at all.  Weird how things work sometimes.  I will never replaced the points and not the condensor again.

We enlarged the wiring diagram with a photocopier at Kinko and it helped a lot in the diagnosis of this problem. 
« Last Edit: August 02, 2005, 05:30:42 AM by lohebohi »

Offline Philly550K1

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #3 on: August 02, 2005, 08:39:29 AM »
my manual has a resistance figure to check the condensors.  did you get a reading on yours, and was your bad one "to spec" per that measurement?

i ask because with the points, anyway, a cursory meter reading isn't always the whole story.  the condensors, i thought failures were uncommon there.  congrats.  with your luck, a coil will go, too.  they're pretty hardy as well, or so i hear.....

:)

stick with it or give it to me.....

-jc

RJBour9912

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #4 on: August 02, 2005, 06:57:31 PM »
18 mm is the correct socket. I just bought a Crasftman for $3.99. I use it with a 3" extension and an 18'' ratchit. All are 3/8 drive. To install the plugs use ONLY the socket and extension....your fingers shouldn't have enough tork to cross-thread. When the spark plug stops turning connect the ratchit to the extension and lightly tug turning only about an eigth of a turn. Remember I am using an 18" ratchit and thats overkill. The goal is to only slightly crush the plug gasket and seal the compression chamber. It's not like you are bolting the steering box to the frame rail of an 18 wheeler that will be hauling 26,000 gallons of gasoline...its just a little spark plug.

Ok if anybody is still reading....also remember that when you tork (tourqe - if you are from accross the pond) you are not always checking to be sure something is tight enough but also or in many cases ensuring that you are not OVERTIGHTNING. Bolts can stretch if overtightend.

I'm still waiting for the title for my 400 SS.....:(

Offline Bob Wessner

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #5 on: August 02, 2005, 07:21:30 PM »
I've been using a U-joint for years rather than a straight extension. It works great for the two inner plugs. I agree 100% re: starting them with your fingers to finger-tight, then use the wrench. Sometimes the chrome on the socket/joint is hard to get a grip on with bare fingers. I keep a pair of cotton gloves that have had latex applied to the palms and fingers (they are garden gloves actually) around just for this, they work great.
We'll all be someone else's PO some day.

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #6 on: August 04, 2005, 06:37:38 AM »
Now 1-4 are not firing.  I am so confused.  I thought I had it.

Here is a short recap of everything.

1. Engine was bogging down when I got to 5000 RPMs under load (driving down the road).  I am not sure if all 4 cylinders were firing, but they may HAVE been.

2. Gunked up carb was the first thought.

3. Manual says to do points and plugs first.  So I changed the points and plugs.  I ran the bike and it was not firing 2-3 cylinders.

4. Lots of troubleshooting; I moved the timing some during troubleshooting (which could alter point gap, etc).  I swapped 2-3 Condensor from parts bike and got 2-3 firing; thus all 4 cylinders were firing.  All 4 cylinders were firing with timing set to where I thought it was, and 2-3 timing plate set to where I thought it was.

5. I took it out for a ride and it ran so much better.  Once the engine was warm I made to hard acceleration runs.  Not like the motorcycle magazines that, to paraphrase, "ran the tach to 10,000 and dropped the clutch".  I just started out normal and quickly opened the thorttle all the way and waited for redline to shift. The engine went all the way to 9,000 RPMs and it had a slight hesitation around 6,000 and 7,000 RPMs but the engine went though those RPM ranges and kept moving.  I assumed the problem was because I tinkered with the timing a little.

6. The engine quickly (after 5-10 miles) went back to normal.  So I got a timing light from a friend.

7.  I moved the circular plate (adjusts 1-4 timing) to around the middle of adjustment.  I did the same thing for the smaller plate that screws onto the circular plate (adjusts 2-3 timing).  I reset point gap.  I skipped the static timing because I cannot seem to understand how (or get it too) that works.  The timing light (and feeling the exhaust) revealed 1-4 were not firing.  The bike has a 2-3 condensor from the parts bike that just allowed the bike to run on all 4 cylinders.

8.  Okay WTF, could the 1-4 condensor have failed within 24 hours of the 2-3 condensor?  I put the 1-4 condensor from the parts bike onto my bike.  The timing light did not go into strobe mode when connected to the No. 1 or No. 4 plug wire.  BUT, the exhaust for 1 and 4 were definately hotter than they were before swapping the 1-4 condensor, but not as hot as 2-3.  Should condensors cost $14 or $24 a piece?  There are two listed in the parts manual and they both cost more than the points.  Just seems odd from my car experience.

9.  Since the bike runs, we checked the timing on 2-3.  We hooked the timing light to the battery.  Hooked the plug wire thing to plug wire number 2, and shined the strobe into the little hole hoping to see the line next to "T2-3" line up with the stationary mark.  Not the case at all.  We could not even see the "T2-3" in the tiny circle window.  We even looked into the window at an angle both ways and could not see  and of the "T2-3" markings, but the bike was running.

10.  Arggg


Side Note:  When I was turning the "special nut" It seemed like my 2-3 points just twisted.  It cause the two point pucks not to line up.  The same thing happened to the 2-3 points that I took off the bike during my initial points swap.  The pucks were far enough off that they would never function again.  $12 down the toilet.  Luckily I had another set in the bag ready to go.  I assumed there was not enough lube on the cam, but it sure seems weird because both sets of 2-3 points were really deformed.  I knew right away when this happened and swapped the points as soon as I saw it.  The cam lobe may not have had ANY grease on it.  I could not tell if I got grease or dirt after a finger swipe.  I greased it up with a tiny bit of water proof grease as per the manual, being careful not to use too much.


lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #7 on: August 04, 2005, 07:35:06 AM »
I understand how static timing is supposed to work.  I follow the procedure for both 1-4 and 2-3 and the test light does not come on, yet the bike runs.  The test light comes on when I probe the + battery terminal so I know the test light works.  I have placed the probe on the ground side of the point breaker.  Come to think of it, why doesn't the yellow wire into the point breaker always have power?  I would think the yellow wire into the point breaker would always have power.  Then when the pucks on the point breaker touch (or arch) the system become grounded, which tells the coil to send a charge through the plug wire.

I place the lead on the tiny bolt that holds the condensor connector and the yellow wire connector into the point.  Then I turn the special nut and the test light never comes on.  Should those two connectors that attach to the point, not be touching?  The bike ran fine when they were touching.

There is continuity between the yellow wire from the coil pack down to the connector on the point breaker.  There is also continuity on the blue(?) wire from the other coil pack down to the point breaker.  I have power coming into the coil pack on a black/white(?) wire that has two female bullet connectors (one goes to each coil pack).




lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #8 on: August 04, 2005, 07:55:51 AM »
Wait!

You disconnect the condensor to do static timing???

That would solve my problem.

Offline Bob Wessner

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #9 on: August 04, 2005, 08:06:47 AM »
In reading through this, a couple of thoughts, I too wonder what you are connecting the static light to if the bike runs, but the light never comes on. Pic below is how I connect it. Also noted references to the T1-4 or the T2-3 marks. You should be using the corresponding "F" marks for timing. The "T" is for valve adjustment or valve/crank alignment on an engine rebuild.
We'll all be someone else's PO some day.

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #10 on: August 04, 2005, 10:12:53 AM »
Sorry I was writing from memory.  I think the mark was "F1-4" and "F2-3".

There is a "T".  I thought the "T" mark was also for advance timing.  I think it said rev to 2500 RPMs and the "T" mark should line up with the marking.  Or something to that effect.  I think it said the "T" was located 23.6 (?) to 26.(?) degrees over from one of the F markers.

I think the test light was not working during static timing becasue I did not disconnect the condensor.

Supersport_CB400F did you forget to attach a pic?
« Last Edit: August 04, 2005, 10:15:19 AM by lohebohi »

ricecake

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #11 on: August 04, 2005, 10:20:41 AM »
9.  Since the bike runs, we checked the timing on 2-3.  We hooked the timing light to the battery.  Hooked the plug wire thing to plug wire number 2, and shined the strobe into the little hole hoping to see the line next to "T2-3" line up with the stationary mark.  Not the case at all.  We could not even see the "T2-3" in the tiny circle window.  We even looked into the window at an angle both ways and could not see  and of the "T2-3" markings, but the bike was running.

I am lohebohi's roommate.  I could see some marks when looking through the peephole, but I don't remember if it was the F2.3 mark or the two marks for checking the timing advance.

The "T" marks indicate Top Dead Center.  As I understand it, there are 6 sets of marks: F1.4, T1.4, timing advance for 1.4, F2.3, T2.3, and timing advance for 2.3.

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #12 on: August 07, 2005, 07:18:47 AM »
So I have started from the begining.  In general; a lot of the tests don't work.

In 100_0238.jpg, I am turned the special nut to the 1-4 marker.  I loosened the three screws that hold the circular plate.  I moved the plate so it can rotate about the same way left and right.  I also discinnected the Condensors to do a chack of static timing.


lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #13 on: August 07, 2005, 07:21:50 AM »
In 100_240.jpg, I have the mark set close to 1-4 in the window and I put the negative lead on the battery and the positive lead (tried both test light and multimeter set to V).  Neither one does anything around the 1-4 mark.  But that is okay since 1 and 4 are the cylinders that are not firing.

The ignition key was turned to run.
« Last Edit: August 07, 2005, 08:02:11 AM by lohebohi »

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #14 on: August 07, 2005, 07:29:17 AM »
In 100_241.jpg, I have turned the special nut to the timing mark for 2-3.  Cylinders 2 and 3 are the ones that are working and propel the bike around the block.  I put the negative lead on the battery (-) and the positive lead of the meter/test light on the teeny tiny bolt that is part of the point breaker unit.  It is the same bolt that you tighten to connect the condensor connector and main power connector.  The test light never came on.  We turned the special nut very slowly.  All the way around twice.  Nothing.  The Clymer says nothing about disconnecting the Condensor in this test.  But the bike runs so I am all confused.

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #15 on: August 07, 2005, 07:31:46 AM »
In 100_244.jpg, I am testing the power into coil.  I would expect 12 V, but 0.22 V seems to run the bike.  The battery yieded around 14-15 while hooked up to the charger.  I checked the battery Voltage just before this. 

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #16 on: August 07, 2005, 07:34:38 AM »
I forgot pic 244.  (Why can't the attachment line be up all the time.  We are living in the google world order, no longer trading nudies pics over modem)

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #17 on: August 07, 2005, 07:35:34 AM »
In 245 I am just showing that the bike runs

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #18 on: August 07, 2005, 07:40:12 AM »
In 248, I am attempting a Condensor test on the Condensor that is working (as evidenced byt he bike going around the block on 2-3).

In 289, I removed the Condensor and tried to perform the test off the bike.  Looks like 1,000 Ohms, not the specified 5,000 Ohms.

Every thing is as it should be as far as I can tell; other than the bogus spec checks called for in the manual.  I am at a total loss.  There is continuity between all the wires in this system.

Offline bryanj

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #19 on: August 07, 2005, 08:06:40 AM »
You DO NOT need to disconnect the condenser!!!! You connect one side of the bulb to ground and the other side to either the Blue OR the Yellow wire with the ignition and kill switch turned on. The "T" mark is ONLY for tappets and cam timing. PLEASE read the book carefully before you destroy the engine
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #20 on: August 07, 2005, 08:58:22 AM »
We have read the instructions in the book ten times.  That is ten times per person.  With three people thatis a total of 30 times.  Why do people keep insinuating that we have not read the book. 

If you think we are not reading the book, point out ONE instance where we did not follow the book to the T.

First someone said to disconnect the Condensors (which made sense based on my understanding of capacitors) which was not in my Clymer.  But I think that step was in said to be in the Haynes.

The reference to the T mark is completely moot.  Since I am not standing in front of my bike, I am using WORDS because I got them letters mixed up last time.  I used the WORDS timing marks.  And by that I meant timing marks.  The ones you use to set static timing.  This circuit is completely simple.  I could draw it in a one square inch box.  I understand the circuit.  I have read the procedure 10 times.   The procedure could not be more simple.  I have done each step in the procedure at least 5 times.  I have removed everything and completely started over twice.

As far as whether or not you need to disconnect the Condensor:  It makes sense to me (but I dropped out of EE) that you have remove a huge current sucking capacitor from the system, but I will let brainj and supersport_CB400F agree to disagree.  As far as I am concerned I have tried it both ways.

lohebohi

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #21 on: August 07, 2005, 12:38:22 PM »
We set the point breaker gap at 0.014 inches.  I believe the Clymer manual said 0.012 to 0.016

.3 millimeters = 0.0118110236 inches

So you are recommending the tighter side of the Clymer spec?  I think I am so close to your recommendation that it would not cause half the plugs not to fire.

CB400FAN

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #22 on: August 07, 2005, 12:55:31 PM »
High. This should be very obvious, but is the points connection to 1 & 4 properly insulated from ground, are the insulating washers in the correct position?    CB400FAN

Offline bryanj

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #23 on: August 08, 2005, 06:27:00 AM »
Points gap is 0.35mm and will alter when you move the points mounting plate so you have to juggle both gap and timing using both the plate adjusters and the contact gap adjusters at the same time. Not easy it comes with years of practice! The bulb need to light when the "F" mark is in line with the static mark as you turn the engine over in the forward direction. The "T" mark is purely for top dead centre finding when cam timing or adjusting tappets, the advance timing marks that need a strobe are simply two lines that the static mark should be between at the prescribed revs. If your bulb does not light you have it connected wrong OR the points arnet opening. If in doubt connect at the blue or yellow wire inside the rubber boot that the rear brake light wires go to. And just to end in 30 years i have NEVER disconnected condensers to do the timing
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline nopivnick

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Re: CB400f - replacing points caused 2-3 to stop firing
« Reply #24 on: September 10, 2005, 05:19:55 PM »
I totally understand your frustration as I've been struggling with similar symptoms caused by equally maddening electrical gremlins. don't freak out if I accidentally misinform, misdiagnose, or tell you something you already know.


In 289, I removed the Condensor and tried to perform the test off the bike.  Looks like 1,000 Ohms, not the specified 5,000 Ohms.

I think your 'reading' may be the indication commonly used on digital multimeters for INFINITE (in this case, no measurable resistance - ohms - because your meter is set to the wrong sensitivity and so rounding off your results). you want your meter set to measure ohms in units of tens-of-thousands. a meter on a 1K or 2K setting is too low (to sensitive) and the display will indicate an INFINITE reading when measuring resistance in the order of 5K. you want a setting of 10K or 20K.


The ignition key was turned to run.

you've said you have the ignition switch on run but don't forget the kill switch needs to be on run, too. I space and forget this often and usually get half way through tearing everything apart before I figure it out. then I usually hit myself in the forehead repeatedly with my fist but it doesn't seem to help me remember any.


In 100_244.jpg, I am testing the power into coil.  I would expect 12 V, but 0.22 V seems to run the bike. 

testing for power-to-coil requires that the corresponding set of points are CLOSED (as well as ignition and kill switches both on run). if you turn the crank (special nut) to test for continuity across points 1-4 then test for power-to-coil 2-3 while points for 2-3 are open, it (power) won't be there. on that note, did you check for power ACROSS your 2-3 points while they were open?



SOMEONE PLEASE CORRECT ME if I've got something wrong here, cause I'm just about at my wits end, too.
« Last Edit: September 10, 2005, 05:26:55 PM by nopivnick »