#1 header isn't getting hot

[seestheday]

Hi All,

Now that I've fixed my carb leaking issue I have found that my #1 header isn't getting hot, indicating that the cylinder isn't firing.

I pulled them plug, checked to make sure that it was sparking (it is, at least when I was holding it), checked the compression (120 psi, not the best, but ok).  #4 was getting hot, so the coil is good (same coil, hooked up as the FSM indicates).  Spark plug smelled like gas.

Also, while I was out there, #3 seemed to be a little intermittent.  Makes me think it the crappy boots/wires.

Other than this being an intermittent problem because my spark plug boots and wires are very cheap, is there anything else that could cause this?

I plan on getting new boots later today.

Surprisingly, the bike was sounding very good considering that it was only firing on 3 cylinders.

[sgtslag]

Only three things are required:  spark, fuel, and air -- in the correct proportions, of course.  If your wires, and boots, are questionable, start with them.

Wires should be copper, not carbon (available on e-Bay, if your local auto shops don't stock the ol' reliable Packard copper wires).  If you are concerned with RFI, then try using Iridium plugs from NGK:  they're resistive, but they still require less voltage to create a spark.  They fire like you have new, modern coils installed.  Let us know what you find.  Cheers!

[seestheday]

Thanks sarge. I already have the iridium coils from last year, and agree they made a noticeable difference when I put them in.

I'll update this thread when I get the new boots and wires in. I picked them up today. Wires I got were definitely copper.

What do you mean by carbon wires? I must be missing something, because carbon doesn't conduct in any meaningful way.

Sent from my BlackBerry device on the Rogers Wireless Network

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From: "sgtslag [via Honda CB750'S]" <[hidden email]>

Date: Tue, 13 Mar 2012 11:05:00 -0700 (PDT)

To: seestheday<[hidden email]>

Subject: Re: #1 header isn't getting hot

Only three things are required:  spark, fuel, and air -- in the correct proportions, of course.  If your wires, and boots, are questionable, start with them.

Wires should be copper, not carbon (available on e-Bay, if your local auto shops don't stock the ol' reliable Packard carbon wires).  If you are concerned with RFI, then try using Iridium plugs from NGK:  they're resistive, but they still require less voltage to create a spark.  They fire like you have new, modern coils installed.  Let us know what you find.  Cheers!

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[shinyribs]

CARBON (SUPPRESSION) CONDUCTORS

Carbon conductors are used in original equipment ignition wires by most vehicle manufacturers, and in the majority of stock replacement wires. This style of ignition wire is cheap to manufacture and generally provides good suppression for both RFI (radio frequency interference) and EMI (electromagnetic interference). Conductor usually consists of a substrate of fiberglass and/or Kevlar over which high-resistance conductive latex or silicone is coated, and functions by reducing spark current (by resistance) to provide suppression — a job it does well while the conductor lasts. Vehicle manufacturers treat ignition wires as service items to be replaced regularly, and limited life is never an issue. This type of conductor quickly fails (burns out) if a high-powered aftermarket ignition system is used.

EMI (electromagnetic interference)

EMI from spark plug wires can cause erroneous signals to be sent to engine management systems and other on-board electronic devices used on both racing and production vehicles in the same manner as RFI (radio frequency interference) can cause unwanted signals to be heard on a radio receiver. Engine running problems ranging from intermittent misses to a dramatic loss of power can result when engine management computers receive signals from sensors that have been altered by EMI emitted from spark plug wires. This problem is most noticeable on modern production vehicles used for commuting where virtually every function of the vehicle's drive train is managed by a computer. For many reasons, the effect of EMI on engine management computers is never predicable, and problems do become worse on production vehicles as sensors, connectors and wiring deteriorate and corrosion occurs. The problem is often exacerbated by replacing the original ignition system with a high-output system.


SOLID CORE CONDUCTOR WIRES

Solid metal (copper, tin-plated copper and/or stainless steel) conductor wires are still used in racing on carbureted engines, but can cause all sorts of running problems if used on vehicles with electronic ignition, fuel injection and engine management systems, particularly if vehicle is driven on the street — and damage to some original equipment and modern aftermarket electronic ignition and engine management systems can occur. Solid metal conductor wires cannot be suppressed to overcome EMI or RFI without the addition of current-reducing resistors at both ends of wires.

[rrgunslinger]

shinyribs wrote

CARBON (SUPPRESSION) CONDUCTORS

Carbon conductors are used in original equipment ignition wires by most vehicle manufacturers, and in the majority of stock replacement wires. This style of ignition wire is cheap to manufacture and generally provides good suppression for both RFI (radio frequency interference) and EMI (electromagnetic interference). Conductor usually consists of a substrate of fiberglass and/or Kevlar over which high-resistance conductive latex or silicone is coated, and functions by reducing spark current (by resistance) to provide suppression — a job it does well while the conductor lasts. Vehicle manufacturers treat ignition wires as service items to be replaced regularly, and limited life is never an issue. This type of conductor quickly fails (burns out) if a high-powered aftermarket ignition system is used.

EMI (electromagnetic interference)

EMI from spark plug wires can cause erroneous signals to be sent to engine management systems and other on-board electronic devices used on both racing and production vehicles in the same manner as RFI (radio frequency interference) can cause unwanted signals to be heard on a radio receiver. Engine running problems ranging from intermittent misses to a dramatic loss of power can result when engine management computers receive signals from sensors that have been altered by EMI emitted from spark plug wires. This problem is most noticeable on modern production vehicles used for commuting where virtually every function of the vehicle's drive train is managed by a computer. For many reasons, the effect of EMI on engine management computers is never predicable, and problems do become worse on production vehicles as sensors, connectors and wiring deteriorate and corrosion occurs. The problem is often exacerbated by replacing the original ignition system with a high-output system.


SOLID CORE CONDUCTOR WIRES

Solid metal (copper, tin-plated copper and/or stainless steel) conductor wires are still used in racing on carbureted engines, but can cause all sorts of running problems if used on vehicles with electronic ignition, fuel injection and engine management systems, particularly if vehicle is driven on the street — and damage to some original equipment and modern aftermarket electronic ignition and engine management systems can occur. Solid metal conductor wires cannot be suppressed to overcome EMI or RFI without the addition of current-reducing resistors at both ends of wires.

I never would have thought!

[seestheday]

Are there different types of resistor covers that I have to worry about as well?
I bought some ngk sb05fp spark plug resistor covers and I was expecting them to just snap on top the spark plugs but they just aren't going.  I've put full bodyweight on them and they're not moving.  Is there a trick I don't know about?

[seestheday]

Oh, and before anyone asks, the ngk plugs I'm using have the thread on cap things on them and the boots are meant for the terminal stud (that's what the "f" stands for in the code per the pdf I looked up).

[shinyribs]

seestheday wrote

 I've put full bodyweight on them and they're not moving.  Is there a trick I don't know about?

Eat more cookies!     who got that?

[TOOLS1]

shinyribs wrote

seestheday wrote

 I've put full bodyweight on them and they're not moving.  Is there a trick I don't know about?

Eat more cookies!     who got that?

TOOLS

[seestheday]

Haha, shiney.

I'm just going to return the boots I got and get ones that will work with threads.  I'll just remove the caps from my current plugs and thread them in.

I plan on running the iridium's from now on anyways, so it won't be a problem for me down the road.

[seestheday]

Sigh, I'm an idiot who just got exposed

The boots I bought originally were meant for the threaded kind of spark plug.  They just snap into place (I had assumed that the boots for threaded plugs screwed in).

I spent a lot of time last night trying to force boots that were meant for threads to snap onto the caps of plugs that were screwed over the threads.



Oh well, live and learn.  I get all the theory easily (Physics degree), and everything in the FSM makes perfect sense to me, but I seriously lack practical experience.

[LukeM]

No need to apologize.  This episode reminds me of the few times that Sheldon's friends get the better of him on The Big Bang Theory.  All the brains in the world, and little Penny zings him with her common sense attitude.  I love it.

Give me a simple man with a boatload of common sense over the book-learned "authority" almost every time.

Luke M

[seestheday]

Haha, thanks Luke.

Well I put the new wires and boots on and my bike now starts as well as my friends new FI bikes.

The old wires were definitely the garbage carbon kind, and the new copper core wires make a huge difference.

I have original coils, Iridium plugs and good quality spark plug wires with good NGK boots.  I'd recommend replacing the wires/boots to anyone.  It was super easy once I figured out that I should be using the threads instead of the caps, and I wish I did it sooner.

I took the bike for a spin last night and there are still a few little things wrong, but overall I'm very happy.

As for the little things, I think my accelerator pump isn't working as well as it could be because the bike is a little slow to respond if I quickly twist the throttle.  My speedometer was also bouncing around a lot, so I'll also dig into why that is happening (I recently lubed it).

[LukeM]

Good deal. I'm glad it's running better.  Finally warming up in TO?

Re the bouncing speedometer needle: Either it's the drive at the front wheel, the cable inbetween, or the speedo itself.  One way to check is to unhook the cable at the speedo end, lay the cable as flat on the floor as you can, jack it up so the front wheel is in the air, and give the wheel a spin.  If the cable is kinked or bent, it'll flop around when the inside turns.  I'm not saying that that is the problem, just another way to diagnose it.

Can't comment on the accelerator pump issue: never had a SOHC 750.  I'm confident you'll figure it out.
Luke M

[seestheday]

Thanks for the tips Luke. I did a little research and narrowed it down to the same things. Good to know I'm on the right track.

I also like the way to test if its the cable.

Sent from my BlackBerry device on the Rogers Wireless Network

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From: "LukeM [via Honda CB750'S]" <[hidden email]>

Date: Thu, 15 Mar 2012 09:48:21 -0700 (PDT)

To: seestheday<[hidden email]>

Subject: Re: #1 header isn't getting hot

Good deal. I'm glad it's running better.  Finally warming up in TO?

Re the bouncing speedometer needle: Either it's the drive at the front wheel, the cable inbetween, or the speedo itself.  One way to check is to unhook the cable at the speedo end, lay the cable as flat on the floor as you can, jack it up so the front wheel is in the air, and give the wheel a spin.  If the cable is kinked or bent, it'll flop around when the inside turns.  I'm not saying that that is the problem, just another way to diagnose it.

Can't comment on the accelerator pump issue: never had a SOHC 750.  I'm confident you'll figure it out.
Luke M

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[LukeM]

That's what  I get for working with motor vehicles for 30+ years, and having a LARGE collection of Haynes manuals. Love the way they write them for guys with ordinary tool kits.

I _think_ you can take the center part of the speedo cable out of the jacket to inspect it.  It may point out in the FSM whether this will work or not.

Luke M

[shinyribs]

Cool idea on the speedo cable! Mine cable slips right out of my jacket FWIW. Makes it real easy to clean like that. My tach does the same.

[seestheday]

Thanks for the tip Lucky.

I jacked up the front wheel, unhooked the cable and spun the wheel.  The cable spins reasonably smoothly, but intermittently.  It'll spin, then stop (while the from wheel is still turning), then spin some more, then stop again.

Seems like it is the gear.  I'll have to disassemble the wheel/speedo case and check the condition of the gear.  Hopefully it just needs to be repacked with new grease.

I put it all back together and now my speedo is effectively not working at all.

Regarding the accelerator pump, it seems to have cleared up.  I'm still running out the gas with the seafoam in it from storage so it's probably cleaning stuff as it goes through.

Also, I don't have a SOHC, mine is a DOHC