Replaced the plugs on the bike: HUGE improvement!

[14Accent]

Per the recommendations of the CB forums, I ordered and installed a set of NGK DR9EIX Iridium plugs to replace the standard DR8EA's that were installed. I have to say, it's a marked improvement. Starts are faster, the idle is smoother, power comes on faster and more consistently. It's just an all around good experience, so anyone with an older bike looking for a cheap upgrade should definitely consider some Iridium plugs.

I found the best price at RA for 4 plugs. Even with shipping, they were $2-5 cheaper for the set than anywhere else. Used a 5% code, as well, of course.

 

[cjcride]

Pictures of the old plugs?

 

[14Accent]

Originally Posted by cjcride
Pictures of the old plugs?


I saved them, I can snap a pic and upload later this evening. They all looked good, maybe a tad lean but not too bad.

 

[DrDanger]

Good write-up. Matches my experience with Iridiums as well.Thanks for posting.

 

[14Accent]

As promised, here's photos of the old plugs. They aren't in order, but they all look identical. Anyone with more experience than me want to chime in and lend an opinion? To me, they look just this side of too lean, but these bikes were tuned lean from the factory for emissions anyhow.

I'd love to hear what the motorcycle guru on this site have to say!

 

[cjcride]

They look fine to me. Thanks for posting.
I've read some plugs seem to perform better in certain engines.

 

[tbm5690]

I put the same ones in about 3 years/6,000 miles ago in my VT1, except mine are the "7" version (hotter plug). Very smooth, and the plugs will easily outlast the bike which is nice.

 

[14Accent]

Just to update, I really haven't been able to ride much lately due to lack of access to ethanol-free fuel in my area... however I finally made a trip with a 5 gallon gas can and filled her up.

Today was the first day I put in some real seat time with the new plugs, both at 7:30 AM with a cool 61 degree temp and this afternoon riding home with temps in the high 70's. I really can't believe how much nicer the bike runs with the new plugs, from less warm-up time to mid-range power, etc. etc. I could go on and on, but I'll just say that the plugs really woke the bike up. Power is just so smooth and seamless, it's hard to believe it's a 40 year old machine. Cruising along at 60 in high gear, hi range, it turns just a touch over 4k RPM and sounds like an old, well oiled sewing machine. It just hums along without a care in the world.

I'm really getting to like this thing... I must admit!

 

[alarmguy]

Your old plugs look just fine, actaully perfect even more so for a 40 year old engine.

 

[electroken1]

I haven't been here for a while but I was employed by a Honda dealer from '83 to '86 when your engine was pretty common. Those old plugs look fine to me with the exception that the gap might be a bit larger than it should be (hard to tell in a photo).

It's not surprising that the idle is smoother with the finer center electrode and likely a smaller gap. I do need to ask why you changed the heat range to one step colder than stock. We never saw any indication that Honda had chosen poorly.

 

[14Accent]

Originally Posted by electroken1
I haven't been here for a while but I was employed by a Honda dealer from '83 to '86 when your engine was pretty common. Those old plugs look fine to me with the exception that the gap might be a bit larger than it should be (hard to tell in a photo).

It's not surprising that the idle is smoother with the finer center electrode and likely a smaller gap. I do need to ask why you changed the heat range to one step colder than stock. We never saw any indication that Honda had chosen poorly.


It wasn't so much a choice as it was the DR9's were easier to find. I'm really only going to be riding in the summer when temps are in the 80's and 90's so I didn't think the bike would mind.

Do you think it would be better to run the DR8's?

 

[electroken1]

A colder plug will tend to foul more quickly but no harm should be done. They're easy to change on that bike if it comes to it.

 

[14Accent]

Originally Posted by electroken1
A colder plug will tend to foul more quickly but no harm should be done. They're easy to change on that bike if it comes to it.


That was my understanding, thanks for confirming. I (assumed) that riding in hot weather and giving the old girl the business at least a couple times every time I ride would keep the plugs from becoming fouled. As you can see by the old plugs, it seemed to be running fine, however I plan on pulling at least 1 of the new plugs soon and comparing to an existing plug to see where I'm at. I've got ~100 miles on the new plugs, I'd like to run at least one tank through to see how they look afterwards.