I am replacing the plugs in my 98 GL1500. I am going to go with the equivalent iridium. (I know the stock do work well)
My question - Do I go with the colder plug or stick with the standard? I have done a lot of reading and besides sticking with the ngk not a lot of info about the heat range on the 1500.
Living in the Southwest - most if my miles are 70mph and above - so above 3000rpm - and add to that riding year round (100F+) and not typically if ever below 40F.
From the manual:
Recommended plugs:
Standard: DPR7EA-9 (NGK), X22EPR-U9 (ND)
For cold climate: (Below 5 ° C/41 ° F)
DPR6EA-9 (NGK), X20EPR-U9 (ND)
For extended high speed riding:
DPR8EA-9 (NGK), X24EPR-U9 (ND)
A thought - I know the iridium plugs take a bit less voltage for spark. So perhaps they will actually fire a bit easier when starting and the voltage drops as the starter is turning over.
Thanks for all of the help!
Spark Plug Heat Range?
- MikeB
- Posts: 3805
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191K Miles
2017 - GL1800 Audio Comfort
28K Miles - Contact:
Re: Spark Plug Heat Range?
I've used many different plugs on many different bikes and I always go back to stock recommended plugs. They just work and do not drain your wallet.
MikeB
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA
- aholloway17
- Posts: 113
- Joined: Sat Jan 28, 2017 10:00 pm
- Location: West Haven, CT
- Motorcycle: 1994 GL1500 Interstate
Re: Spark Plug Heat Range?
I've had a 94 for three years now. I switched from the OEM plugs to the NGK and they just work. The bike runs very smoothly and when I check them the color is perfect.
Happy choosing!
Happy choosing!
1994 GL1500 Interstate
- DenverWinger
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'80 GL1100 STD Vetter (2005-)
'93 GL1500 Aspencade (2017-)
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Past rides
'72 CL350 (1980-1988) sold
'78 Suzuki GS550 (1985-2005) sold
'77 GL1000 (2002-2006) sold
Re: Spark Plug Heat Range?
Last maintenance I unscrewed the back two plugs on the 1500, looked at them (stock NGK) and screwed them back in. Bike runs perfect, the two plugs had good color, still looked like new.
These plugs were in the bike when I bought it 4 yrs ago.
No reason to go further.

No reason to go further.

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♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫

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♫ 127 Little Bugs in the Code. ♫ ♪

~Mark
- bellboy40
- Posts: 988
- Joined: Fri Nov 27, 2009 1:13 pm
- Location: Brewton, AL
- Motorcycle: 2000 GL1500SE Candy Spectra Red
Re: Spark Plug Heat Range?
I bought a 94 1500SE back in 2010 and while doing all the changing of fluids, filters, belts, etc., I removed the plugs and changed them with the stock NGK plugs. The ones I took out looked near perfect with just a tan color at 25,000 miles. If I hadn't already bought new plugs, I would have put those back in and rode it.
I sold that one and bought a 2000 1500SE with about 70,000 miles on it and those plugs looked about the same as the ones I took out of my 94. I have no idea if they were ever changed before I got it. I went ahead and replaced those with some new stock NGKs. Bike was running great before I changed them and still does.
Also, I bought a new GL1200 LTD off the showroom floor in 85 and after I had put about 70,000 miles on it, I pulled the plugs and they still looked nearly new. I put some new ones in and I couldn't tell any difference in how it ran or the gas mileage after replacing those plugs. I guess my bottom line is this: With the unleaded fuel we are running now, those plugs will last a long, long time.
I sold that one and bought a 2000 1500SE with about 70,000 miles on it and those plugs looked about the same as the ones I took out of my 94. I have no idea if they were ever changed before I got it. I went ahead and replaced those with some new stock NGKs. Bike was running great before I changed them and still does.
Also, I bought a new GL1200 LTD off the showroom floor in 85 and after I had put about 70,000 miles on it, I pulled the plugs and they still looked nearly new. I put some new ones in and I couldn't tell any difference in how it ran or the gas mileage after replacing those plugs. I guess my bottom line is this: With the unleaded fuel we are running now, those plugs will last a long, long time.
- Rambozo
- Posts: 2126
- Joined: Sun Apr 01, 2018 8:36 pm
- Location: Disneyland
- Motorcycle: 1992 GL1500 Aspencade
Ducati Monster
Re: Spark Plug Heat Range?
Last I checked, NGK is the OEM for Honda.aholloway17 wrote: ↑Sun Apr 25, 2021 7:08 am I've had a 94 for three years now. I switched from the OEM plugs to the NGK and they just work. The bike runs very smoothly and when I check them the color is perfect.
-
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Re: Spark Plug Heat Range?
I am currently using the autolite XS4164 iridium you may not believe this but last set got 88k on them before any misfire developed,so I highly recommend them no rattle or ping from engine they just last a long time.no better mileage though..
- MikeB
- Posts: 3805
- Joined: Fri Dec 04, 2009 12:54 pm
- Location: Tacoma, WA
- Motorcycle: 1998 - GL1500 Aspencade
191K Miles
2017 - GL1800 Audio Comfort
28K Miles - Contact:
Re: Spark Plug Heat Range?
OEM NGK plugs are only about $15 a set of six. Honda recommends replacing them every 12K miles or so.
OEM plugs work great. I've never had one foul or misfire and they do not drain the wallet.
OEM plugs work great. I've never had one foul or misfire and they do not drain the wallet.
MikeB
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA