Topic: Upper engine tick and possible smoke from exhausts

[gmoneymagna]

The bike
1982 CB650 Nighthawk with 12k miles. SOHC I4. I purchased it with ~7k miles 4 years ago. I regret I have previously been a poor motorcycle owner and have not done proper maintenance aside from regular oil changes, although I have taken steps to perform schedule maintenance on my motorcycles.

I recently did a valve adjustment and had a slight issue afterward that I fixed. You can read here for more http://forums.sohc4.net/index.php?topic=174756.0;all#lastPost. I also sync'd the carbs and they were all already close to each other. However they were not in the "normal" range for my gauge but I'm not sure what the normal value really means.

The problem

• Tick from upper right side of the engine that increases with rpms and is louder after bike is warm
• The tick is not new since before the valve adjustment but the smoke is
• Stumbles at low RPM with aggressive throttle input - This is not really new and may just be a characteristic of the i4 engine

The workup

• All four exhaust bikes are hot.
• All valves are within spec

Current hypothesis

• Maybe damage to the top of the engine due to not adjust valves for 5k miles? Or loose valve lash causing more noise?
• The smoke might be caused by valve cover gaskets going bad. I inspected them before reinstalling and they looked in good shape and I put a bit of oil on the gasket cover before installing

Future plans

• Not really sure. Maybe get a new valve cover gasket

I have attached some video files. I appreciate your time and help!

https://drive.google.com/open?id=1dh95xDBySEOstcuhmCII8zdPfBUXSucb
https://drive.google.com/open?id=1jeSE_oeoFBMAzX9mx0TeFJMo4T13Y_c9
https://drive.google.com/open?id=18QgfuVoCSxzLgMGe3qETaIu1LYd7yTwg

[bryanj]

Have you had the exhausts off? A slight gasket blow can give you a tick that sounds like a tappet. Got the tee shirt for that one

[brewsky]

A leaky donut exhaust gasket can sound an awful lot like a valve tick.

Ooops…..Bryan beat me to it!

[Deltarider]

Maybe do the valve adjustment again and do it one cylinder at a time to avoid any mistake.
Have you checked for sparking between plugcaps/wires and head (= Ground). Best done in the dark.
White smoke is usually condens. Does it smell?

[Don R]

 Is the smoke from the mufflers or coming off the engine?  If it's cold where you are it's probably just condensation especially if you take short rides and don't heat up the exhaust pipes.  Re check the valve lash, if you adjust at the wrong spot in the rotation it will leave the rocker arm loose. 

[gmoneymagna]

Have you had the exhausts off? A slight gasket blow can give you a tick that sounds like a tappet. Got the tee shirt for that one

Exhausts have not been off. Perhaps it is my mind but there might be some difference in exhaust note from right to left. It may sound different from when I bought it but that's hard to tell as it has been nothing drastic. Do these fail on their own? I have no idea if this one is original and almost 40 years old.

[gmoneymagna]

Maybe do the valve adjustment again and do it one cylinder at a time to avoid any mistake.
Have you checked for sparking between plugcaps/wires and head (= Ground). Best done in the dark.
White smoke is usually condens. Does it smell?

Has some oil smell but I think that it is from the valve cover gasket installation which left a film of oil near the top. It is cold and wet where I live right now. The smoke is not constant. The only thing that worried me was the wisps of smoke that persisted after the bike was off as shown in the video. I think it may have stopped at this point. The spark plugs are new and I have not gapped them yet. The tool will arrive soon.

I've never heard of the spark plug grounding in the head. Would that cause ticking?

[gmoneymagna]

Is the smoke from the mufflers or coming off the engine?  If it's cold where you are it's probably just condensation especially if you take short rides and don't heat up the exhaust pipes.  Re check the valve lash, if you adjust at the wrong spot in the rotation it will leave the rocker arm loose.

I can recheck the valve this weekend. So far I have almost quadruple checked the valves and done them both as the Clymer's manual says and cylinder by cylinder with each at TDC. Please see my above post about the smoke. I think it has stopped.

[Tracksnblades1]

Gmoney.
Remove spark plug boot from number 4 spark plug. Sit it back on plug but do not snap it down. Place a long zip tie (non conductive) around wire so you can remove it when engine is running without getting a charge (shocked). Start engine and take the boot on and off while engine is running. Listen if the tapping, clicking, snapping, noise changes. Move the boot 3-4 inch away from spark plug or metal so the ignition can not jump a spark to anything. Inside some NGK sparkplug boots there is a resistor that helps provide a longer duration coil discharge to the spark plug. Eliminate spark jumping to ground sound (above post) before adjusting valves again. Sometimes coil discharge (spark) can jump (arc) to ground inside or around boot or wire. That arcing sounds like a clicking or snapping sound. In the dark like posted above you'll be able to possibly seeing the wire light up or actually see the arcing if it is not inside the boot in the resistor area. HondaMan has good post of resistor requirements and the need for spark plug boot replacement.  Your video of the exhaust smoke looks like condensation vapor or water boiling off in exhaust. It looks white in the video.

[Tracksnblades1]

Gmoney,

Smoke from valve cover leak will be localized in that area. Blue smoke ( oil consumption) in the exhaust generally is caused from valve stem guide wear and/or  valve stem seal failure, as well as the dreaded piston rings / cylinder wear. Generally oil from a leaking valve cover can not directly enter the exhaust system. It is common for engine exhaust to emit water vapor until the temperature of the exhaust rises.  Additionally higher or lower engine idle rpm is one of many conditions that can cause gauge discrepancies between observed reading and service manual recommendations when syncing carbs.

[Deltarider]

Inside some NGK sparkplug boots there is a resistor that helps provide a longer duration coil discharge to the spark plug.

Where did you get his from? There's no literature on this, let alone that Honda mentions this. Sofar nobody has demonstrated a longer duration scopewise. Always eager to learn, I have asked three parties (science, board of automotive mechanics and a member magazine for automotive professionals), they probably didn't know what to do with the question as I never received an answer. Although I'm open to the possibility, I doubt there's an effect. If there was, we most likely would have heard of this trick. The only thing we KNOW the resistor does there, is suppress noise and that's exactly what Honda* and NGK refer to. In all NGK's extensive tuition there's nothing on a longer duration. I'd hate to see people empoverish good working 5kΩ noise suppressing by adding a 5kΩ extra which, in our waste spark systems would mean 20kΩ in one circuit. That's a lot.
* In my possesion is a beautifull, 100 page French manual on the CB500-550 that was constituted in close cooperation with Honda France. It's the only source in my collection that advises on resistor plugcaps: to be abandoned when over 8kΩ...

[Little_Phil]

If it's a leaky exhaust gasket, the tick will stop if you remove the plug cap from that cylinder.

[gmoneymagna]

If it's a leaky exhaust gasket, the tick will stop if you remove the plug cap from that cylinder.

you mean the spark plug boot? As is make the cylinder not fire and the sound should go away?

[Tracksnblades1]

Gmoney,

http://forums.sohc4.net/index.php?action=dlattach;topic=7401.0;attach=109843;image

This is a picture of the resistor within a sparkplug boot. (Borrowed from Hondaman USA.)

Testing for ignition to ground arcing is separate from exhaust leaks.

[Tracksnblades1]

Inside some NGK sparkplug boots there is a resistor that helps provide a longer duration coil discharge to the spark plug.

Where did you get his from?   
  AIEE

There's no literature on this, let alone that Honda mentions this.
 I'm sure Honda is aware of effects of ignition resistance prior to the advent of radio rf.

 Sofar nobody has demonstrated a longer duration  Scopewise
I believe with any review you can find more than a few.

Always eager to learn,
A combination of disciplines always leads to enlightenment.

 I have asked three parties (science, board of automotive mechanics and a member magazine for automotive professionals), they probably didn't know what to do with the question as I never received an answer.
I would include these guys to your reputators.  IEEE,  these guys have a voice of their own and they'll be able to answer your queries.

Although I'm open to the possibility, I doubt there's an effect.
Positive and Negative = Negative.

 The only thing we KNOW the resistor does there, is suppress noise and that's exactly what Honda* and NGK refer to. 

Is your inference then, "Resistance"  in the secondary ignition had never been implemented prior to radio fr concerns...?  By Honda..?  By NGK..? By Aviation...?

In all NGK's extensive tuition there's nothing on a longer duration.
I believe with some review you shall find NGK is very aware...and I'm not speaking for them...


* In my possesion is a beautifull, 100 page French manual on the CB500-550 that was constituted in close cooperation with Honda France. It's the only source in my collection that advises on resistor plugcaps: to be abandoned when over 8kΩ...

That very nice..

[Little_Phil]

If it's a leaky exhaust gasket, the tick will stop if you remove the plug cap from that cylinder.

you mean the spark plug boot? As is make the cylinder not fire and the sound should go away?

Yes stop that cylinder firing. If it's a mechanical source the sound may change, if it's a exhaust gasket it will stop.

[TwoTired]

Thee problem of spark wire pulling in diagnosis  is that you break the circuit path for two cylinders when pulling a single lead, resulting in two dead cylinders.  The technique is more effective with a distributor type ignition system.

Yes, the resistors are there to reduce radio emmissions.
They do this by reducing the spark spike amplitude and redistributing that energy to a later time in the discharge cycle, thus extending the spark.  This is a well known technique in EMI/RFI reduction engineering, which I did as a vocation for 10 years.

The CB 550 came stock with 10k ohm resistor caps. That's 20k ohm in the coil secondary circuit for thousands of well running bikes.  Hard to find these anymore as manufacturers trimmed their line offerings to save money.  But, I used to get them from the Honda dealer in town as proper replacements 20 years ago.

The higher loop resistance was paired with the hotter heat range plugs that the 550 used. Most likely to extended the hotter plugs usefull life.  Colder plugs in other bikes more often had less secondary loop resistance 10 k ohms total.  The only exception appears to be the Canadian market where the government mandated more resistance in their imports in an effort reduce radio emissions more drastically.

I think the 650 uses D8EA, which is a colder plug offerring than the 550s D7EA.

Cheers,

[Tracksnblades1]

Oh..Gee..This is a learning curve for me.

It's like revisiting Dr. Demmings "Continuous Improvement Plan" don't hear any more about Japanese junk these days.

What I've learned on GMoney thread:

1) Gmoney is getting his 650 running good again.
2) Gmoney is trying to locate the source of a ticking noise.
3) "        " is recieving assistance for differentiating between electrical arc and mechanical sounds.
4) RESISTANCE in the Secondary circuit is for rfi/Emi attenuation only.
5) My old 750 can't miss on only 1 cylinder. (Three pipes hot).

I am slow and old but this old dog it trying to accept this new instruction (tricks).

For so long I believed in the now antiquated findings of those original designers and inventors like but not limited to : Tesla, Bosch, Champion, Simms, Lenoir, Toyota, Siemens, lodge and others.

For all this time I believe as I read published findings the advent of the resistance in the secondary circuit was to primarily provide:

 A longer service life of the sparkplug, by reducing *current* at the gap. (I can remember changing plugs every 5000mi.)

 I believe these referenced gentlemens' findings include resistance introduced within the secondary circuit provides a sharp intense clean spark pulse of sufficient duration to provide consistent ignition to the compressed mixture. When viewing oscilloscope (scopewise) images you may notice a cleaner more defined start/stop and longer spark pulse duration as compare to only the resistance supplied by the spark gap in the compressed mixture. Additional images (scopewise) may support the same introduced resistance at the beginning of the spark discharge can attenuate start (ripples, dribbles dc slang or leakage, re-rectifying ac slang) voltage variations which may affect consistent ignition. At the end of the same discharge ( scopewise) cycle you may observe those same ripples dribble, voltage oscillations this time those effects being contributed to arc gap contact area erosion / gap component(s) wear. Which I believe would be of additional interest in a wasted spark ignition since this would be 2 stroking the spark plugs.

Current aviation specs place secondary (sparkplug test resistance) acceptable resistance between 500ohms - 4000ohms. With replacement of any value under or over. I think you can find research indicating valves as low as 400ohms can provide all the benifits to spark arc gap components preservation as compared to significantly higher resistance values. Military maintenance codes may have adopted this research also. I don't think you'll read of any requisite  rfi/Emi suppression requirements  in the military/maint/aviation spark plug codes.

Perhaps my interpretation of these gentlemens and those currently expanding on those findings are in error....?  I can still remember when Rfi/Emi were shielded with sheet metal (old Corvettes)or faraday cages.

I can't speak for anyone of them or "HondaMan" but they all knew this.

Perhaps as we have hijacked Gmoney thread, someone can start a thread covering sparkplug resistance and the benefits thereof.
 
EL my bike doesn't even have a radio, I can find some more rope though.....

[Deltarider]

There is 10kΩ and there is... 10kΩ. It is possible that Honda fitted 10kΩ plugcaps on some models, although personally I have serious doubts. From what I've seen, my impression is that OEM plugcaps were 6-7kΩ. In the first year I owned my CB500, I discovered that I had one (only one) plugcap that read around 10kΩ. Having no documentation on it, for me it was impossible to find out if that one was a genuine 10kΩ Honda plugcap or let us say a 7kΩ that had reached the end of its lifetime and needed to be renewed. This because one of the other plugcaps that looked similar OEMish read 7kΩ. The other two had already been renewed by the PO's dealer. I called Honda The Netherlands and the man for technical support told me all 4 plugcaps should read more or less the same and he advised me to use 5kΩ plugcaps.
You can choose whatever plugcap you want, but know that the 10kΩ NGK plugcap is no longer available. Now what I'm against is the advice I've read several times in this forum: to have both the 5kΩ resistor plug and the 5kΩ resistor cap to mimick a presumed 'original' 10kΩ resistor plug. Wait a minute! Who says it was original 10kΩ? As far as I know, we-do-not-know. That's one and two: what is advised here, does not result in the same as having that presumed original 10kΩ resistor plugcap. Why? Well, because instead of two transition ends, you'll have four and that is a serious factor in reliability. That's why I don't like that idea at all. Then this: as far as I know there are NO complaints by riders that stay on the safe side and run 5kΩ resistance. It was and is generally advised by official Honda dealers. The longer spark duration with a 10kΩ resistor plug is hypothetical and that's as far as I can go, not having seen any evidence. I'm open for the possibility, but I haven't heard of such an effect, let alone that I've witnessed it. And if there would be an effect, we still have to find out if it is significant enough to make such a difference that we can notice it in practice. What I know for a fact - and I think we all can agree on this - is that a 10kΩ resistor transforms more energy in heat than a 5kΩ.
But there is consolation for us all: a standard healthy ignition with 5kΩ resistor plugcaps offers a burning time at the electrodes during plenty degrees crank rotation. So why risk it? For what?
I challenge folks that insist it was original 10kΩ to order a genuine CB500/550 plugcap at CMSNL and inform us what resistance it reads. Depending on which one you choose, it will only set you back € 21,- or € 26,50 a piece. A bargain to end uncertainty, if you ask me.

[Tracksnblades1]

Found these 10k ohm ones on NGK.com. Don't know what they fit, just looking to see if they still offered a 10k ohm for a motorcycle application. One would have to verify the 10k ohm as NGK advertises .

[TwoTired]

What I've learned on GMoney thread:

4) RESISTANCE in the Secondary circuit is for rfi/Emi attenuation only.

Not true.  Resistance squeezes off current flow, and delays the depletion of the coil energy during the event.  This lengthens the event and delays the rise time of the spark pulse.  The rise time delays also lowers the frequency component of the signal, which reduces RFI/EMI emissions.  This is a function of the coil secondary loop resistance, which includes the coil resistance and any added resistance place in the loop between coil output leads.  Less current through the spark gap of heated plugs leads to less errosion of the metals used for the spark electrodes.  Iridium survives this without much loss at higher voltage and current levels.

5) My old 750 can't miss on only 1 cylinder. (Three pipes hot).

I don't know where this came from.  But, of course it's not true.  If you are referring to a spark lead removal, remember that the coil secondary needs a complete path for current to flow.  Path is: one coil lead to spark plug, across gap to cylinder head, to other paired spark plug, across its gap to the the other spark lead and back to the coil secondary.  A shorted spark plug across electrodes or fouled insulator will allow current to flow in the circuit allowing the other plug to still fire, as will a grounded spark lead of the "dead" cylinder.  Simply removing the spark lead from one cylinder breaks the current loop of the coil secondary.  As no small gap exists anymore the secondary keeps building voltage to its limit in order to find a gap to bridge.  Insulation leaks may provide that path.  But if the insulation holds the energy in, then two cylinders will fail to fire as no current can flow through the spark gap of two cylinders.

Current aviation specs place secondary (sparkplug test resistance) acceptable resistance between 500ohms - 4000ohms. With replacement of any value under or over. I think you can find research indicating valves as low as 400ohms can provide all the benifits to spark arc gap components preservation as compared to significantly higher resistance values. Military maintenance codes may have adopted this research also. I don't think you'll read of any requisite  rfi/Emi suppression requirements  in the military/maint/aviation spark plug codes.

As the aviation practice is to jacket shield all ignition components to block RFI/EMI radiation, resistance in the coil or magneto spark output is relegated to only a current limit function by circuit design.  Shielding is expensive, so other methods of RFI/EMI suppression are employed in motorcycles of the seventies, I.E. series resistance. 
Series resistance is also employed in computer equipment for the same reason.  Faster computing cycles demand short windows to determine a digital high or low signal.  Circuit drivers can change state very fast, often faster than actually needed.  The fast rise times make any wire or trace a radiating source, which can be received by any neighboring wire, behaving as an antenna.  (Can also radiate outside the unit enclosure.)  Series resistance is frequently employed to slant/slow the rise times, which reduces the frequency component of the signal change and radiated energy.  The trick is to select the correct resistance for the wire or trace characteristics, while still enabling the state sampling circuit to read correctly in the required window a true high or low in the digital signal.

Perhaps as we have hijacked Gmoney thread, someone can start a thread covering sparkplug resistance and the benefits thereof.
This is true.  And you state a worthy goal.  But, people in the Netherlands hijack threads to evangelize their own flimsy and unsupported opinions quite frequently.  And this is not the first time.  No quantifiable facts provided are necessary in such broadcasts, (though they are demanded to be received).
 

EL my bike doesn't even have a radio, I can find some more rope though.....

It's not so much your personal radio that is of concern to others.  It is any nearby wire that behaves as a receiving antenna for the energy radiated by your ignition wires.  Then it is a matter of what is attached to that wire, whether it is sensitive to the energy received.  RF differentiator, or computer circuit, etc. and what threshold to which they can reject noise and still respond to a usable, valid signal.

[TwoTired]

There is 10kΩ and there is... 10kΩ. It is possible that Honda fitted 10kΩ plugcaps on some models, although personally I have serious doubts.

Ooooh, your doubt causes me indescribable pain.   But, I invite you to come and measure my collection of 550s.  They all have 10 K plug caps.  90% are still originals from Honda. (They don't have the NGK impression on them, the replacements do, though).

From what I've seen,... I discovered that I had one (only one) plugcap that read around 10kΩ.
Having no documentation on it, for me it was impossible to find out if that one was a genuine 10kΩ Honda plugcap...

Thanks for that inconclusive, anecdotal, unusefull report.  I'm sure we can all file it away where it belongs.

Now what I'm against is the advice I've read several times in this forum: to have both the 5kΩ resistor plug and the 5kΩ resistor cap to mimick a presumed 'original' 10kΩ resistor plug.

Great.  Pick an opinion without facts or reason.  Regardless, follow me!  Nice.

Wait a minute! Who says it was original 10kΩ?

That's what the Honda part reference number got me when I replaced a broken cap 20 years ago.  Had to order it, as the ones he had in stock were all for bikes that had D8EA heat range plugs.  The replacements measured...wait for it... 10 K ohms, just like the other three on the bike.

As far as I know, we-do-not-know. That's one and two: what is advised here, does not result in the same as having that presumed original 10kΩ resistor plugcap. Why? Well, because instead of two transition ends, you'll have four and that is a serious factor in reliability.

Oh really? Care to quantify that "serious" factor?  Are you saying the MTBF calculation says failure is imminent in 1000 years rather than 2000 years?

That's why I don't like that idea at all. Then this: as far as I know there are NO complaints by riders that stay on the safe side and run 5kΩ resistance.

So, your questionair canvas of no people led you to a conclusion there is no issue?  That's junk science fiction at its most fictional.  Here's another;  I've also noted the lack of complaints when I fart in public.  Therefore, I submit my farts don't stink to anyone but me.
Do you even read the rubbish you post?

It was and is generally advised by official Honda dealers. The longer spark duration with a 10kΩ resistor plug is hypothetical and that's as far as I can go, not having seen any evidence.

You haven't looked or have the where-with-all to prove or disprove, either.  You only have keyboard access to make unsupported assertions, with repeat capability.

... What I know for a fact - and I think we all can agree on this - is that a 10kΩ resistor transforms more energy in heat than a 5kΩ.

In theory, that's true.  As far as that goes.  But, is a quantification of one Joule of energy really of concern out of the total joules sourced from the coil?

But there is consolation for us all: a standard healthy ignition with 5kΩ resistor plugcaps offers a burning time at the electrodes during plenty degrees crank rotation. So why risk it? For what?

Another red herring argument.  For one, the spark duration is only a portion of the power stroke in either the lower or higher resistance cases.  Neither lasts the entire power stroke.  But, longer is better for a more complete burn.
But, risk? There is no risk to keeping the design parameters of the original product.  The way I see it, you are asking others to take a risk of a design change based on no practical data.  For the 550, I expect the risk is losing spark plug effective life when increasing the secondary loop current, as well is a small impact on fuel mileage.
What is your fuel mileage?  Don't you think a longer duration spark could improve that?

I challenge folks that insist it was original 10kΩ to order a genuine CB500/550 plugcap at CMSNL and inform us what resistance it reads. Depending on which one you choose, it will only set you back € 21,- or € 26,50 a piece. A bargain to end uncertainty, if you ask me.

Again someone else to do the research for you AND pay for your "education".  Such a master manipulator!

But, how do you know that CSML didn't change their stocking procedure based on part availability from the manufacturing source based on an accountants desire to have product to sell with the best profit margin?

As a design engineer, I've had the part procurement department change vendors due to either availability or parts cost.  Never mind that the operational specs for the part number were actually different, and could not be guaranteed to work in the design.  Which was why we had to qualify all the parts and vendors we specified.

Are we having fun yet?

[bryanj]

TT i just love your answers mate, you are a breath of fresh air in a world full of obnoxious smells!!