Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: McCabe-Thiele (Ted) on November 13, 2023, 02:41:08 PM

Title: Correct spark plugs for my 500 ?
Post by: McCabe-Thiele (Ted) on November 13, 2023, 02:41:08 PM
Parts manual shows NGK D-7ES or Denso X-22ES

The Denso seems to now have a U at the end now shows as Denso X-22ES-U

The NGK looks as though it is obsolete - I have resistor caps so don't want NGK DR-7ES.

Green Spark Plug Co shows the Denso X-22ES-U at good price.

Can't find my old spark plugs - I've been using some used NGK D8EA plugs to keep debris out.

Title: Re: Correct spark plugs for my 500 ?
Post by: Nurse Julie on November 13, 2023, 02:45:14 PM
Denso X22ES-U is the correct type.
Title: Re: Correct spark plugs for my 500 ?
Post by: Johnwebley on November 13, 2023, 03:18:35 PM
If you ride it, quite quickly, for a 70s bike

Mine runs great on the 24s



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Title: Re: Correct spark plugs for my 500 ?
Post by: deltarider on November 13, 2023, 04:09:52 PM
In The Netherlands dealers advised the D8ES-L (or the ND equivalent). The "7" was considered the plug for break-in period only. This was advised because we used to ride at maintained high speeds. US riders usually have the 7. They prefer to ride at lower rpm's.
Title: Re: Correct spark plugs for my 500 ?
Post by: Bryanj on November 13, 2023, 06:33:21 PM
IF you can find any D7EV are the muts nuts but expect to pay £8 ish EACH
Title: Re: Correct spark plugs for my 500 ?
Post by: mickwinf on November 13, 2023, 10:13:42 PM
d7es replaced by d7ea.
Title: Re: Correct spark plugs for my 500 ?
Post by: AshimotoK0 on November 13, 2023, 11:43:46 PM
Denso X22ES-U is the correct type.

Going to go with these Julie as heard there are a lot of fake NGK's around. Do you have a reference for ND for CB750K0 and 400/4 please?
Title: Re: Correct spark plugs for my 500 ?
Post by: Sesman on November 13, 2023, 11:50:42 PM
I don’t believe Greenspark supply fake NGK. Just saying…..
Title: Re: Correct spark plugs for my 500 ?
Post by: davidcumbria on November 14, 2023, 07:08:14 AM
I’ve gone for the denso ones from green spark who didn’t have the ngk in stock at the time. Run iridium in most of my bikes which definitely help starting but can’t see one for the 550.
Title: Re: Correct spark plugs for my 500 ?
Post by: deltarider on November 14, 2023, 08:07:06 AM
[...] Run iridium in most of my bikes which definitely help starting but can’t see one for the 550.
Any new sparkplugs will help starting. Some in the German forum have tested iridium plugs but were not impressed. These plugs will do well in modern bikes however which run much leaner than our filthy beasts.
Title: Re: Correct spark plugs for my 500 ?
Post by: K2-K6 on November 14, 2023, 08:26:49 AM
Denso X22ES-U is the correct type.

Going to go with these Julie as heard there are a lot of fake NGK's around. Do you have a reference for ND for CB750K0 and 400/4 please?

Original std for 750 K0 listed as D8 ES in Honda workshop manual, no equivalent for ND. Later manual lists D8 EA with ND "X24ES-U" as direct alternative. 
Title: Re: Correct spark plugs for my 500 ?
Post by: Nurse Julie on November 14, 2023, 08:30:33 AM
Denso X22ES-U is the correct type.

Going to go with these Julie as heard there are a lot of fake NGK's around. Do you have a reference for ND for CB750K0 and 400/4 please?
X24ES-U Ash.
Title: Re: Correct spark plugs for my 500 ?
Post by: K2-K6 on November 14, 2023, 08:31:19 AM
[...] Run iridium in most of my bikes which definitely help starting but can’t see one for the 550.
Any new sparkplugs will help starting. Some in the German forum have tested iridium plugs but were not impressed. These plugs will do well in modern bikes however which run much leaner than our filthy beasts.
It's primarily about service life and gap change during that lifing to meet intervals in schedule as opposed to significant changes in performance of the plug.
Before these materials they were heading toward twin and triple earth type plugs for durability (typically toward 36,000 miles in car engines) ultimately superseeded by this type of plug with more resistant materials.
Title: Re: Correct spark plugs for my 500 ?
Post by: Bryanj on November 14, 2023, 10:00:48 AM
Many years ago our NGK rep was  gent called Stan Dibden who used to be a sidecar racer, just by looking at the plugs from a GT 250 he advised stripping as a piston was holing and he was right.
He also gave me a set of D7EV for my 500 and i found it started cleaner, ran better and gave better mpg.
That plug has been long discontinued and if you can find them its £8-10 EACH, i am lucky to have bought a few sets years ago
Title: Re: Correct spark plugs for my 500 ?
Post by: Skoti on November 14, 2023, 12:12:08 PM
Aye,

Stan Dibben former sidecar world champion, NGK spark plug rep and recent vice president of the Norton owners club.


Here's a clip from the New York Times  https://youtu.be/V_8vr_4qa2g (https://youtu.be/V_8vr_4qa2g) (7mins)

Title: Re: Correct spark plugs for my 500 ?
Post by: philward on November 14, 2023, 01:34:53 PM
Great watch

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Title: Re: Correct spark plugs for my 500 ?
Post by: davidcumbria on November 14, 2023, 04:26:19 PM
[...] Run iridium in most of my bikes which definitely help starting but can’t see one for the 550.
Any new sparkplugs will help starting. Some in the German forum have tested iridium plugs but were not impressed. These plugs will do well in modern bikes however which run much leaner than our filthy beasts.
It's primarily about service life and gap change during that lifing to meet intervals in schedule as opposed to significant changes in performance of the plug.
Before these materials they were heading toward twin and triple earth type plugs for durability (typically toward 36,000 miles in car engines) ultimately superseeded by this type of plug with more resistant materials.

I have found empirically that The pin head electrode  in iridium plugs does produce better performance in some bikes. Less fouling and better idling and starting on all my two strokes. Notable better starting on my xt250 single which is a well known tricky starter. I wouldn’t waste my money buying them had I not seen irrefutable improvements in several fourstroke and two stroke engines versus new non iridium.  It’s not just about longevity it’s about the shape , power and consistency of the spark.
Title: Re: Correct spark plugs for my 500 ?
Post by: Bryanj on November 14, 2023, 05:50:44 PM
Stan was the travelling rep for a London firm near Wembley called Mobyke i think, the imported the rotary engined german bikes which the press wrecked the demos of(dkw?) Also did Marvin exhausts which were incredibly loud if you removed the baffle but being Italian the chrome fell off!
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