Author Topic: 400F intermittent losing spark on cylinders 2/3 (Dyna S)  (Read 218 times)

0 Members and 1 Guest are viewing this topic.

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
400F intermittent losing spark on cylinders 2/3 (Dyna S)
« on: October 08, 2018, 01:21:13 am »
I think my first question that I need help with is regarding a Dyna Ignition.
When they go bad is it an intermittent problem or is it a dead or alive situation?

Every once in a while my 400F loses spark on #2/#3 cylinders. It will cut out while I am riding (dry weather) and it feels like the bike is running out of gas and then it kicks in again. The problem is occurring more often now than it used to. It can be running on two cylinders, I turn off the ignition, turn it back on and it is running on all 4 cylinders again. I verified with a timing light today that it is 2/3 dropping out.

My set up
Dyna S, Dyna 3 ohm coils, Accell wires and caps (I think), verified grounds on coils. I have checked all connections related to the Dyna S and the Dyna coils. Everything looks good. There is a conductive grease (from the factory) between the Dyan S pick-ups and the points plate, ignition advance is working properly and lubed. Gasket on the points cover is new.

Thoughts?




'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 18,790
  • I refuse...
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #1 on: October 08, 2018, 03:27:49 am »
The historic issue with the Dyna S failing is an intermittent issue. It seems many encountered this issue when the unit got hot. You can test that theory by removing the points cover and running the bike (in dry weather of course) to see if it makes any difference.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

*** Currently experiencing life at 60 WTFs per hour ***
I always thought getting old would take longer

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #2 on: October 08, 2018, 04:15:36 am »
The historic issue with the Dyna S failing is an intermittent issue. It seems many encountered this issue when the unit got hot. You can test that theory by removing the points cover and running the bike (in dry weather of course) to see if it makes any difference.

Thanks calj737,
It is doing it even when the engine is cold, but just knowing that it can be intermittent when the Dyna S fails is good information.
In Japan there is another brand of aftermarket electronic ignition that includes the coils and trigger. It isn't cheap, but neither is a new Dyna S every year. I might switch over.
'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 18,790
  • I refuse...
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #3 on: October 08, 2018, 04:18:16 am »
Some of the Southern Hem guys run Boyer-Brandsen units with great success. I don't think we have ready access to it in this part of the world without significant shipping.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

*** Currently experiencing life at 60 WTFs per hour ***
I always thought getting old would take longer

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #4 on: October 08, 2018, 04:24:17 am »
Here is a pic of the "Wotani" brand ignition system. It's about $800 and the instructions are in Japanese. It does have an adjustable rev limiter...
'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 18,790
  • I refuse...
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #5 on: October 08, 2018, 05:00:39 am »
$800? Wow, pricey. The C5 is about $500 with coils, wires and optical ignition. Has programmable ignition curves too. Might give that a look if you're willing to spend money on an all new setup. Personally, I think you could simply replace/swap the ignition plate with another type/brand and be fine. (The C5 requires use of their coils.)
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

*** Currently experiencing life at 60 WTFs per hour ***
I always thought getting old would take longer

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 20,519
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #6 on: October 08, 2018, 08:38:47 am »
Check your battery voltage.
The Dyna-s and 3 ohm coils is known to pull so much more power that the 400 alternator has a difficult time keeping the battery charged.   If you must use 3 ohm coils, get a 1 ohm resistor to put in series with the power supplied to the coils.

Having said that, it still may be to late to save your Dyna-s.  Maybe manufacturing defect, maybe over stress.  But, I'd still want to know what voltage it is operating at before declaring the unit defective.  Can't expect it to behave if getting fed scantily.

Cheers,
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

Thinking:  It's like reading with your own mind

Offline PeWe

  • Really Old Timer ...
  • *******
  • Posts: 6,696
  • Bike almost back to the 70's 2015
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #7 on: October 08, 2018, 10:54:10 am »
I had Dyna-S with 3 ohm coils for short while. Battery drained really quick when I had headlight on, LO H4 of 55W. Went back to the shop and changed the 3 ohm coil to 5 ohm coils. They had max 1 hour.
It is easy after that experience to crank up the charging by adjusting the regulator. Over voltage might be a Dyna-S killer?
I installed a LED that supervise the charging level after that. I noticed occasional overcharging (flashing red LED). Adjusted the regulator and since then good charging level.
I replaced the Dyna-S with stock points and Hondaman ignition too. Less risk to get a failure on a dark road and probably rainy too when happen ;)
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 stock looking project started 2017

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 20,519
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #8 on: October 08, 2018, 11:17:35 am »

It is easy after that experience to crank up the charging by adjusting the regulator. Over voltage might be a Dyna-S killer?
I installed a LED that supervise the charging level after that. I noticed occasional overcharging (flashing red LED). Adjusted the regulator and since then good charging level.
The "voltage regulator" doesn't do what many think it does.  It is a protection device to keep the battery from seeing overvoltage when fully charged.  It only indirectly controls system voltage by keeping the battery in a charged state.  The battery dominates, not the charging system, which is way weaker when the components are in proper operating condition.
Can you compensate some for voltage losses seen by the Vreg?  Yes.
Will that mean when those losses are fixed the battery will overcharge on long rides at cruise?  Yes.

Most of the problems with the charging system is that the Vreg can't monitor true battery voltage due to degraded wire connectors fuse contacts or switch contact degradation.  Fix those before you go tweaking the Vreg, and you won't have to worry about cooking your battery when the lights are off on long off idle cruise durations.

Cheers,
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

Thinking:  It's like reading with your own mind

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #9 on: October 08, 2018, 02:55:35 pm »
Thanks for the input guys.
Interesting comment about the charging system and battery possibly being the fault. And I can understand that as being the issue, if it was a constant, but being as it is so random, I am reluctant to buy into it as the cause in this case.

Here is a little more information that might help narrow down the possibilities.
The battery is about 5 months old.
I keep the bike on a battery tender.
 I can ride for hours with out issue, or I can ride for 5 minutes and the problem pops up for a few minutes and then goes away on its own or after I restart the bike.
The problem has recently become much more prevelant ~ which is a good thing as it will make it easier to troubleshoot.

I have blade style fuses, the sub-harness between the field coil/stator is new, the connectors on the field coil/stator are also new (the problem was present before these were installed), and the wiring harness is in top notch condition.

I was dreaming about this problem last night and in my dream what I came up with was that the wire for the #2/#3 trigger to the coil was grounding out. Today I will do some more troubleshooting

Also, unrelated but food for thought, I have a Dyna S and 3 ohm (green) coils on two of my other 400F's, they've been installed for years and never had any issues with them. But I also run a relay to the coils on those bikes......

Thanks for taking the time to read my post and lend some brain power (I need it!!).

Kevin

'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #10 on: October 08, 2018, 09:41:22 pm »
I did some more inspection/troubleshooting today...with no conclusions  :'(

Initial start up all 4 cylinders were firing.
Battery voltage is at 12.95vdc
Wire harness and connectors look great.
The spark plug wire boots at the coil (#2/#3) appear to be touching the top of the motor so I thought perhaps I have an arcing problem. I rerouted the wires and started the motor, still have spark on all 4 cylinders.
While futzing around the motor started to idle a little rough, I thought it was fuel starved since the gas tank was off, so I put the tank back on and started the motor again to see how it goes, #2/#3 are dead!
Great! Now I can isolate the problem!! I started wiggling the wire harness, the plug wires, the wires going into the Dyna S...nothing changes!
I pulled the tank back off to see if it possibly has something to do with it and nothing changed.

I took a lunch break and thought I'd grab some new spark plugs to throw in just to see it's effect.
I get back to the bike, put the gas tank back on to fill up the float bowls, hit the start switch and the motor is firing on all 4 cylinders again! Argh!!
While it was running I unplugged the yellow wire going to the #2/#3 coil and of course it started to run like crap again and died. Plug the yellow wire back in and it is still no spark on #2/#3.
So I may have just killed my Dyna ignition....hopefully that really was the problem this whole time.

If I had any hair on my head I surely would have pulled it all out trying to troubleshoot this.


'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #11 on: October 09, 2018, 12:01:14 am »
A few hours after my last post I went back to the garage, uncovered the 400F, put the key in and hit the start button.
It fired right up with all 4 cylinders singing away.

Although reluctant I am leaning toward ordering a replacement Dyna S and maybe installing the 1 ohm resistors as recommended to save on the battery drain.

I'm still interested in hearing what thoughts you guys might have.

Thanks!
'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline JoeCooley

  • Long time lurker, but now I'm a
  • Hot Shot
  • ***
  • Posts: 256
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #12 on: October 09, 2018, 12:53:11 am »
I had the same problem with Dyna S. Intermittent failure of 2-3. Got a used setup from a buddy. Swapped it in and the problem is gone. The Dyna S works good for what it is but they do #$%* the bed after a while.
BUY MY PARTS, FUND MY ADDICTION!!!!
http://forums.sohc4.net/index.php/topic,172582.0.html

Joe in San Diego - Proud Owner of Quick Cyles
78 CB750K 836cc Highway Racer - http://forums.sohc4.net/index.php/topic,162264.0.html
2001 Triumph Sprint ST 955i - http://forums.sohc4.net/index.php/topic,164743.msg1901503.html#msg1901503

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #13 on: October 09, 2018, 01:11:24 am »
I had the same problem with Dyna S. Intermittent failure of 2-3. Got a used setup from a buddy. Swapped it in and the problem is gone. The Dyna S works good for what it is but they do #$%* the bed after a while.
Thanks Joe! 
The previous owner of this bike said this Dyna S was a warranty replacement.
Unfortunately it is no longer under warranty...


Sent from my SM-G955F using Tapatalk

'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 18,790
  • I refuse...
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #14 on: October 09, 2018, 03:23:36 am »
I think you need a new ignition plate.  :-[ These symptoms are exactly what is described by virtually everyone who ends up with a Warranty Dyna.

I don't believe your plugging/unplugging the Yellow wire had any adverse effect on its lifespan.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

*** Currently experiencing life at 60 WTFs per hour ***
I always thought getting old would take longer

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #15 on: October 09, 2018, 04:13:16 am »
I think you need a new ignition plate.  :-[ These symptoms are exactly what is described by virtually everyone who ends up with a Warranty Dyna.

I don't believe your plugging/unplugging the Yellow wire had any adverse effect on its lifespan.

Thanks Cal, I looked at their warranty and it is for one year and to the original purchaser only. I guess it is worth a try.
I think their quality is crap nowadays, I wonder where they have their parts manufactured?
They used to offer a decent product, when I was in the parts selling business I sold tons of their stuff. Now I feel bad for any of my old customers who ran into products with Dyna products.
'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 18,790
  • I refuse...
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #16 on: October 09, 2018, 04:24:28 am »
Yeah its odd, they seem to have this lingering issue. But it also seemed that is was limited to older units, perhaps made a few years back. Possibly this unit is from "old stock"? Who knows... It just plain sucks that new stuff doesn't last as well as old stuff  >:( Kind of like Millenials  ;D ;D
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

*** Currently experiencing life at 60 WTFs per hour ***
I always thought getting old would take longer

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #17 on: October 09, 2018, 04:42:57 am »
Yeah its odd, they seem to have this lingering issue. But it also seemed that is was limited to older units, perhaps made a few years back. Possibly this unit is from "old stock"? Who knows... It just plain sucks that new stuff doesn't last as well as old stuff  >:( Kind of like Millenials  ;D ;D

Hahaha....Millenials!

So I just went thru the big stack of paperwork that was sent to me by the previous owner to see if I could determine just how old this Dyna S unit is, I came across a receipt from Z1 Enterprises dated May of 2006. If that is the unit that is installed now I guess I can't complain too much......but still, it's supposed to be "Set it and forget it"!

Looks like I will be ordering another unit...... :(

Thanks for all the help, I really appreciate it!

'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 20,519
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #18 on: October 09, 2018, 07:45:04 am »
If you have another 400 with a dyna s, why don't you swap them bike for bike to see if the problem follows the unit?

Cheers,
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

Thinking:  It's like reading with your own mind

Offline ttr400

  • Hot Shot
  • ***
  • Posts: 534
    • ttr400 Projects and Billet parts.
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #19 on: October 09, 2018, 10:54:51 am »
Kevin is in Japan, his other bikes are in the States.

I also had an issue some years ago, same thing would drop 2/3 cyls. i changed out the dyna S and was OK. it was on a 350F race bike.

Kevin
CB400F- 492 Yoshi Racer.
Cb400F- 466 Yoshi Cafe.
CR750 D Mann Replica.
VFR750R- RC30 - 1988.
www.ttr400.com

Offline Kevin

  • Enthusiast
  • **
  • Posts: 214
Re: 400F intermittent losing spark on cylinders 2/3 (Dyna S)
« Reply #20 on: October 09, 2018, 02:45:11 pm »
If you have another 400 with a dyna s, why don't you swap them bike for bike to see if the problem follows the unit?

Cheers,

Great idea!! But as TTR400 stated I don't have access to my other Dyna S units....:-(

Kevin is in Japan, his other bikes are in the States.

I also had an issue some years ago, same thing would drop 2/3 cyls. i changed out the dyna S and was OK. it was on a 350F race bike.

Kevin

Thanks Kevin, I am in Japan this week, but will be coming to see you in South Africa in about 10 days!!! Yeah!
Kevin
'75 CB400F Retro "Purple Haze"
'75 CB400F Cafe'
'75 CB400F Red Rooster Rocket
'76 CB400F Parakeet Yellow ~ Stock
'77 CB400F 701 Mile bone stock Candy Anteres Red
'98 Suzuki Intruder VS1400 ~ for long rides
And a couple of CB400F's in boxes for future projects :-)

 

;