Honda CX 500 Forum banner
1 - 17 of 17 Posts

·
Registered
‘78 CX500
Joined
·
8 Posts
Discussion Starter · #1 ·
Okay. I’ll try to keep it short.

my new (to me) cx500 seems to lack some pep and seems to run better on the left cylinder than the right. I swapped the spark plugs after some tinkering with other things to see if there’s a difference. Seemed to help some BUT when I pull the plugs theyre D7EA NOT D8EA, which from what I e read is stock. Would this cause issues? I am planning on replacing them as theyre cheap and if it helps at all I’d be happy but want to ensure I use proper parts.
Any help or guidance is appreciated.
 

·
Super Moderator
'84 CX650E that is evolving into a GL500
Joined
·
17,292 Posts
The FSM says D8EA for all CX500 models with CDI.

As you can see from the chart below, the number indicates the heat range of the plug and 7 is one step hotter than 8. The GL500 FSM recommends 8 heat range as standard with 9 for high speed extended riding and 7 for cold weather (below 41f/5c). FWIW, I use 8s in mine all winter (DR8ES-L for my GL500 engine).

It is possible that your bike's PO changed to 7s for cooler weather or to attempt to deal with the plugs fouling, or even in an attempt to compensate for the effects of the pod filters. Or that he just bought the wrong number and didn't notice.

Unless someone with more knowledge of pod filters tells you different I would recommend using the stock 8s in a place as warm as Texas.

Font Parallel Pattern Event Number
 

·
Registered
‘78 CX500
Joined
·
8 Posts
Discussion Starter · #3 ·
The FSM says D8EA for all CX500 models with CDI.

As you can see from the chart below, the number indicates the heat range of the plug and 7 is one step hotter than 8. The GL500 FSM recommends 8 heat range as standard with 9 for high speed extended riding and 7 for cold weather (below 41f/5c). FWIW, I use 8s in mine all winter (DR8ES-L for my GL500 engine).

It is possible that your bike's PO changed to 7s for cooler weather or to attempt to deal with the plugs fouling, or even in an attempt to compensate for the effects of the pod filters. Or that he just bought the wrong number and didn't notice.

Unless someone with more knowledge of pod filters tells you different I would recommend using the stock 8s in a place as warm as Texas.

View attachment 210208
Awesome. I looked into it more while waiting and noticed the heat range difference. Went ahead and snagged the D8EA plugs.
thank you for the reply and knowledge!
 

·
Registered
‘78 CX500
Joined
·
8 Posts
Discussion Starter · #5 ·
I'd wager you're having carb issues especially if the bike has been sitting for any length of time.
It starts and runs okay but the throttle response seems sort of slow. I am hoping to pull the carbs and clean them soon and really look at the pilot jets as I’ve heard they can cause some of the issues.
having said that, the plugs did seem to help some as well so that’s a plus! Thanks
 

·
Super Moderator
Joined
·
5,160 Posts
Have you done the stator resistance checks? It is easy to do and should be one of the first things done when chasing running problems with a CDI bikke.
 

·
Registered
Joined
·
1,387 Posts
Unless you are a real carb guru you might want to invest in Larry's book (forum member) CX500/Gl500 Carb book (donlhamon.com) Getting them really clean and tuned correctly is more difficult than most people think.
 

·
Registered
‘78 CX500
Joined
·
8 Posts
Discussion Starter · #9 ·
Have you done the stator resistance checks? It is easy to do and should be one of the first things done when chasing running problems with a CDI bikke.
Have not done that but will look into it.
Thank you!
 

·
Super Moderator
Joined
·
2,846 Posts
  • Like
Reactions: D-Fresh

·
Registered
Joined
·
2,685 Posts
CXPHEAK is probably right but you may want to run some seafoam in the gas in the meantime, can't hurt and it's cheap.
 

·
Registered
1978 cx 500 cafe
Joined
·
5 Posts
Okay. I’ll try to keep it short.

my new (to me) cx500 seems to lack some pep and seems to run better on the left cylinder than the right. I swapped the spark plugs after some tinkering with other things to see if there’s a difference. Seemed to help some BUT when I pull the plugs theyre D7EA NOT D8EA, which from what I e read is stock. Would this cause issues? I am planning on replacing them as theyre cheap and if it helps at all I’d be happy but want to ensure I use proper parts.
Any help or guidance is appreciated.
I would also look at a set of carburetor kits ,had trouble with balancing my cx 500 but after replacing and cleaning of the internal of the carb she ran sweet as ,good luck buddy,
Cheers yab
 

·
Registered
Joined
·
18 Posts
It starts and runs okay but the throttle response seems sort of slow. I am hoping to pull the carbs and clean them soon and really look at the pilot jets as I’ve heard they can cause some of the issues.
having said that, the plugs did seem to help some as well so that’s a plus! Thanks
Before you pull the carbs run "Mechanic in a Bottle" through it. It's a super card cleaner and in most cases I have found once you use it you don't need to pull the carbs. Also go score some ethanol free full, these bikes never were designed to run on the crappy gas they sell these days.
 
1 - 17 of 17 Posts
Top