Author Topic: Honda CB550 Spark Plug Wires (Read 1204 times)

kyle750 · « **on:** August 16, 2025, 10:07:27 PM »

I'm quickly learning that parts for the CB550 are harder to find than the CB750. The spark plug wires on my CB550 are a mess of cracked wires and electrical tape holding together falling apart end caps. It really is astonishing that this bike started up at all. I have not checked the condition of the ignition coils but I understand they are very durable and almost never fail.

I have started a search for replacement wires and caps. The spark plug caps for the CB550 are at unusual angles and not too many available options. 4 into 1 makes replacements but I have read warnings that they are not very good quality and have a tendency to fail quickly. NOS Honda CB550 caps are available but too expensive for me. I believe NGK caps would be the best way to go if I could find them

Not sure on spark plugs but NGK and ND seem to be the favorites on the SOHC forum. I have a NOS TEC (Toyo) CB550 points plate ordered as my points plate is also a mess!

Deltarider · « **Reply #1 on:** August 16, 2025, 10:51:05 PM »

For caps go NGK. Excellent quality and way cheaper than OEM.

kyle750 · « **Reply #2 on:** August 16, 2025, 11:08:18 PM »

For end caps on the CB550 =

2 at 120 degree angle and
2 at 90 degree angle

Deltarider · « **Reply #3 on:** August 17, 2025, 12:10:36 AM »

Kyle, the 05F indicates they're 5 Ohm. That's good. Now, angled or not and to which degree, just choose the ones that will fit your bike best. Some, like me myself, have the straight ones for 2+3 because I had to trim the wires a bit. As far as wires, do not choose resistor wires. They have a carbon core that can become brittle. Iron or copper core is good. It's up to you, if you want to keep the coils or not. You can fit new wires (shown in the UK site https://info.sohc.co.uk/download/ashs-ignition-coil-fix-2/) or choose new coils with wires and all. This forum can inform you which aftermarket coils will do. A cheap option is to fit NGK cable couplers. http://forums.sohc4.net/index.php/topic,42400.msg438731.html#msg438731

kyle750 · « **Reply #4 on:** August 17, 2025, 12:57:59 AM »

I am hoping the old coils test at 5 ohms? I really should inspect and test the ignition coils before proceeding. Lots of original coils that have been taken from parted out bikes are available if I find they need to be replaced. Many have been tested at 5 ohms by the sellers. Maybe not always the most reliable testing but you have to place some faith in the information provided by the seller in the item description. Often with used Honda parts it is just a roll of the dice - sometimes you win and sometimes you lose.

I am VERY HESITANT to buy used 50 year old ignition components

kyle750 · « **Reply #5 on:** August 17, 2025, 01:06:36 AM »

I've also noticed the newer end cap main body appear to be made out of plastic. Earlier caps were more of a rubber material. Is this correct? If this is true than I suspect I am going to have a hard time with inflexible plastic.

Deltarider · « **Reply #6 on:** August 17, 2025, 01:47:26 AM »

No, you won't. Honda had quite a struggle with plugcaps, seen how often they changed. They first had metal shrouded ones and they were really, really bad. I don't think NGK's are 'plastic' seen the origin of the word. According to the published rider reports the plugcaps have always been the CB500/550s Achilles heel. The 4 cylinder is so 'forgiven' that it can take a wile before you notice, not all is well, the more when misses occur intermittently. The softer caps - you say rubber - can after some time - become porous and arc right through that rubber to the head and that's where you do not want your spark, now do you? Keep the caps clean to avoid a parasitic drain. WD-40 can be a good help. But after 20.000km expect having to replace them. Also see to it the HT wires are not contacting the head.

bryanj · « **Reply #7 on:** August 17, 2025, 01:54:37 AM »

I have been told by a trader that NGK are no longer making plug caps so get them asap.
Careful what you buy as some need the screw on tip and some dont, i will try and look up the correct numbers for you

kyle750 · « **Reply #8 on:** August 17, 2025, 03:59:51 AM »

Correction??

2 short stem 120 degree
2 long stem 90 degree

kyle750 · « **Reply #9 on:** August 17, 2025, 04:35:55 AM »

Expensive at $116 plus shipping from Japan but looks convenient and easy to install. Shipping normally arrives very quickly from Japan

Description from the seller:

The size of the cord is 7mm Φ, the same as the genuine one. The black plug cap is made by NGK. The plug cord is made by Kijima and uses 7 copper core cables with high conductivity, and the outstanding insulation power of silicone rubber and super glass fiber completely shuts out electrical leakage. It also has excellent durability.

Deltarider · « **Reply #10 on:** August 17, 2025, 07:03:33 AM »

Haven't seen those before. Could you give a link? Silicone is very durable. When the wires are very, very supple like mine (by Dynatek), pay extra care they will not move around too vehemently in the riding wind. If those caps do not have the inbuilt 5kOhm resistor, you would have to turn to R(esistor) type plugs to be streetlegal and I'm not a fan of them... and I'm not the only one.

kyle750 · « **Reply #11 on:** August 17, 2025, 08:02:21 AM »

Non-resistor end caps should be paired with non-resistor plugs? Correct? How can you tell if end caps are resistor or non-resistor type?

kyle750 · « **Reply #12 on:** August 17, 2025, 08:35:47 AM »

As a slight detour into CB750 plug caps the original Honda caps would be the older style non-resistor type and work well in combination with the non-resistor plugs?

bryanj · « **Reply #13 on:** August 17, 2025, 09:25:05 AM »

If you can get them you need XD05F and SD05F.
The straight ones for centre cylinder the bent for outer two.

Carefull what you order as both are available in red or black

kyle750 · « **Reply #14 on:** August 17, 2025, 09:34:47 AM »

Thanks mate. Very confusing but I get confused very easily.

Are the NGK XD05F and SD05F resistor or non-resistor end caps?

kyle750 · « **Reply #15 on:** August 17, 2025, 10:03:20 AM »

I could very well be wrong but I am getting an awful sinking feeling that many of the NGK plug caps sold on ebay are fake. Inferior quality stamping and no box supplied.

Little_Phil · « **Reply #16 on:** August 17, 2025, 10:21:44 AM »

The 05 designates 5k ohms resistor in plug cap. Normally these are recommended to use with non resistor plugs. But I have used with resistor plugs in the past and didn't have a problem, but others have.

Deltarider · « **Reply #17 on:** August 17, 2025, 12:33:52 PM »

Imagine you on your bike at a traffic light, next to a police patrol car. If you have no noise suppression at all (that's what that resistor is for), your ignition will disturb the radio in the police car and you'll be fined. So you need a resistor either in the plug cap or in the plug itself to avoid interference. Maybe you remember the old days when we all had TV antenna's on our roofs. If a moped, car or bike passing by didn't have noise suppression in its HT route, you would notice it on your TV screen. To have noise suppression is the law. To have a resistor in both cap and plug is not recommended. For modern bikes it doesn't matter where you have the resistor: in the cap or in the plug. Quite some owners of a SOHC Four prefer it this way: the resistor in the cap and not in the plug. I'm one of them. My CB500 doesn't like R(esistor) plugs.

kyle750 · « **Reply #18 on:** August 17, 2025, 04:42:06 PM »

Quote from: Deltarider on August 17, 2025, 12:33:52 PM

Imagine you on your bike at a traffic light, next to a police patrol car. If you have no noise suppression at all (that's what that resistor is for), your ignition will disturb the radio in the police car and you'll be fined. So you need a resistor either in the plug cap or in the plug itself to avoid interference. Maybe you remember the old days when we all had TV antenna's on our roofs. If a moped, car or bike passing by didn't have noise suppression in its HT route, you would notice it on your TV screen. To have noise suppression is the law. To have a resistor in both cap and plug is not recommended. For modern bikes it doesn't matter where you have the resistor: in the cap or in the plug. Quite some owners of a SOHC Four prefer it this way: the resistor in the cap and not in the plug. I'm one of them. My CB500 doesn't like R(esistor) plugs.

I appreciate the additional information about resistor vs non-resistor. I am a firm believer in abiding by all the laws and regulations where I live. Laws are different in every country in the world and in every state in the US. Were the laws requiring resistor components designed to benefit society overall or the machine itself - in this case a 50 year old Honda Engine designed before resistors were in widespread use??

Ebay has strict rules against counterfeits and yet I suspect there are fake NGK plug caps everywhere on the site?

bryanj · « **Reply #19 on:** August 17, 2025, 05:09:07 PM »

Honda had to design to meet the standards of counties they sold which is why it states on the vin plate the year nd that it complies, for example Honda motorcycles in uk did not require vin plates till arround 76/77
I think Honda specify the D7ES for the 550 you have which was replaced by the D7EA, if you can find any get D7EV but these were discontinued years ago and were expensive but i can tell you from personal exerience that a 500 started better, ran crisper and gave more mpg just by changing plugs

kyle750 · « **Reply #20 on:** August 17, 2025, 06:09:25 PM »

Thanks Mate! Plenty of Authentic NOS NGK D7ES for sale in the US at $16 for a set of 4 or $4 each (with free US shipping)

Yesterday I learned that NGK spark plugs are also widely counterfeited and sold online and ebay (incredible to see the highly accurate detail of the fakes). No one unknowingly wants cheap chinese copy counterfeit end caps or spark plugs in their bike.

Would a long shelf life affect the integrity (50 year old material) or performance of these plugs?

Late Edit: How cool is the old NGK Japan packaging with see through window

kyle750 · « **Reply #21 on:** August 17, 2025, 09:43:01 PM »

The answer from AI

Spark plugs do not have a specific shelf life in terms of years, but their lifespan is determined by usage and wear, not by how long they've been stored. They can last for a very long time if stored properly and not used. However, once installed and used in an engine, they have a finite lifespan measured in miles or hours of operation, depending on the type of plug and engine.

If spark plugs are stored properly, in a cool, dry place, and protected from moisture and contaminants, they can last indefinitely.

Spark plugs don't expire on the shelf, but they do wear out with use and need to be replaced when they no longer perform adequately.

Typical AI disclaimer "AI responses may include mistakes"

Deltarider · « **Reply #22 on:** August 18, 2025, 12:13:20 AM »

If you have the choice between the D-7ES and D-7EA, I'd opt for the latter. If you opt for no resistor in the caps (not my preference) you will need the -R version of forsaid plugs. If you choose to run without any resistor, which is against the law, you will be a plague for all those along your route who listen to AM radios/watch TVs with antennas.

kyle750 · « **Reply #23 on:** August 18, 2025, 12:29:56 AM »

Quote from: Deltarider on August 18, 2025, 12:13:20 AM

which is against the law

I believe you are wrong . . . perhaps in your home country but not here in Thailand where I live. But I'm not a lawyer and I'm not here to debate laws or motorbike regulations in all the different countries of the world.

kyle750 · « **Reply #24 on:** August 18, 2025, 12:45:16 AM »

I'm a really old timer decades behind in the adoption of the latest technology . . . but . . .

Who still listens to AM radio?
Who watches TV with an antenna?

Late Edit: I just did a quick check and emergency vehicle responders and law enforcement personnel do not use AM radio for communication

News:

Author Topic: Honda CB550 Spark Plug Wires (Read 1204 times)