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Discussion Starter · #1 ·
Hey everyone,
I recently cleaned and rebuilt the carbs on my 1980 CX500D using Larry's book, and am having a strange issue (may be unrelated to the carb cleaning, but thought I'd mention it). It runs and rides well for the most part - took it on a 150 mile jaunt around the Olympic peninsula with no issues, before it started raining every day here in the PNW. Only issue I'm having is sometimes (but not always) it will lag at half or more throttle. It always runs fine when accelerating gently, but if I really twist it it will lag on me. Then, if I hold the throttle in that position, often it will "catch" after a couple seconds and I'll get a kick in the butt and take off.

I think it happens more when the engine is fully warmed up, although I also don't tend to go hard on the throttle when it's not warmed up. I've also tested to see if it will rev (right after this happens) and it revs to 9K no problem if I pull the clutch. It's also not always the case, with the engine warm I'd say I have a 30% chance of it happening at any given time.

Any idea of where to start? Electrical issue? Carb issue? Any help would be appreciated. I do have a multimeter and any/all hand tools.
 

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Discussion Starter · #4 ·
Thanks littlebr4d. That's entirely possible, I'll try backing out the idle screws a half turn and see if that helps
 

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Do a spark plug reading to determine if too rich or too lean before turning screws. Are you certain that your accelerator pump is working properly?
 

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Just on an off chance because I had this happen while riding in the rain, are the drain holes in each cylinder head clear? I had one plug up a little and the water couldn't drain fast enough. It started shorting the plug voltage to ground.
 

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Run a restistance check on the coils when they are warm. Remember, to test both sides of each coil to ground.

One may be failing when warm.
 

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Discussion Starter · #8 ·
Do a spark plug reading to determine if too rich or too lean before turning screws. Are you certain that your accelerator pump is working properly?
Good call, will do. I am not certain that the accelerator pump is working, but I did rebuild it using Larrys book and Randakk's kit so I would assume so.
 

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Along with all the other good suggestions, try this quick easy test ... After its good and warm take it for a spin if/when it starts to lag/bog. Pull the choke out just a bit (1/16"-1/4") not to much, if it perks up you'll have a better idea if its carb related or other.

BTW welcome to another PNW rider. Keep an eye on the travel/trip section for a possible spring time group ride.

Also if needed I can loan you (short term) an Ignitech unit to help rule out or confirm stator/CDI issues.
 

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Discussion Starter · #13 ·
SLiM - thanks so much for the very generous offer. Sounds like I've got a few other things to try first, but if I can't get it figured out I may contact you. I'd love to join in on a group ride, I've got another buddy here in Seattle with a CX500C that I'm sure would be down too. I'll keep my eye out. Cheers
 
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