help front plug runnin lean back plug rich

Energy One
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wyatt580

Well-Known Member
last up grade was new ignition everything was ok before that. plugs both the same color. bike ran great.... please any suggestions would be great .with plugs runnin different[lean /rich] bike surges around 2500rpm went up on intermedite to 33.. main seems fine 76. airbleed is 78 with 2 thunderjets.everything fine until new thunderheart ignition :bang::bang::bang::bang::bang::bang::bang: ive tried 0-4 on the timeing settings...no difference have pitcher of plugs but don't know how to put in.they were new plugs 2nd set of new. i know the frt cylinder runs colder then the back because of airflow but not that different .... how do i get the plugs the same is it ignition timeing or carb adjustment??????????????????????????????????????????
 
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oldmutt

oldmutt

Active Member
My front plug has been running rich and my rear plug is normal since I got the bike 6000 miles ago. It runs great so I am leaving it alone.
 
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wyatt580

Well-Known Member
both of mine looked good till new ignition and there wasn't any surging at 2500 rpm before. thanx for reply
 
Staffy

Staffy

Active Member
Not saying its normal but definitely common. Can we get a pic of each plug.
Do you have a small black cap on your carb? Make sure that it is in good condition and not cracked. Also although im not sure this is relevant the air bleed seems high and might hold back the main from kicking in until much later.
 
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wyatt580

Well-Known Member
the carb is a taz not home but don't think i've seen a black cap .i've got a pic but don't know how to post it?? airbleed was a 68 had some touble before and bob at xxx helped me with it. what we ended with is 78 witch is as big as recommended.since bike was runnin ok before ignition do you think ignition timeing?? i was thinking carb but can't get the plugs close and the surging is driving me nuts
 
PROFLYER

PROFLYER

SWOLE
Its whatever you screwed with last. If it was running fine, then you changed the ignition, that's probably it. If the timing is adjustable for each cylinder (i'm not sure how your new ignition works) it could be firing early just a tad which will leave some unburnt fuel and foul the plug. I know my front runs a tad richer then my back but that's because the front cylinder stays cooler, just the nature of the beast...but it's not a huge difference. The guy who tuned mine said you always tune the rear because if you make the front fine the rear could be too lean and too lean is worse then a tad rich.

Anyway, I'd check the ignition if everything was fine before and that's the only thing you've messed with.
 
Mickeetwo

Mickeetwo

Guru
PROFLYER said:
Its whatever you screwed with last. If it was running fine, then you changed the ignition, that's probably it. If the timing is adjustable for each cylinder (i'm not sure how your new ignition works) it could be firing early just a tad which will leave some unburnt fuel and foul the plug. I know my front runs a tad richer then my back but that's because the front cylinder stays cooler, just the nature of the beast...but it's not a huge difference. The guy who tuned mine said you always tune the rear because if you make the front fine the rear could be too lean and too lean is worse then a tad rich.

Anyway, I'd check the ignition if everything was fine before and that's the only thing you've messed with.
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Got to agree with Proflyer. Good advice
 
Staffy

Staffy

Active Member
Let's try process of elimination......
First off what made you change the stock ignition? Does it still work and if so what would it take to put it back on? If not much let's give it a try and see if the bike performs as previously and all is well with "both" plugs. Depending on the results we can take next steps.
Just a thought...This way none of us are second guessing.
 
mobsta

mobsta

Well-Known Member
Did you have the exhaust off when you did the ignition change?An exhaust leak can cause a problem with heat.just sayn
 
mastiffdave

mastiffdave

Well-Known Member
My plugs crapped out at Bike blues and BBQ this year. They only had a couple hundred miles on them after a complete going over and a new exhaust at Iron Lightning. The bike was running perfect up untill fri night and then the surging started at about 2500 rpm . Next the bike craps out on 540 , after changing the plugs it runs perfect. The front plug was darn near black and the back one was like its supposed to be. Ive put 750 miles on the new ones and both are like they are supposed tp be. I believe its was just defective plugs cause the new ones with more miles are just fine.
 
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wyatt580

Well-Known Member
didn't need to take pipe off for ignition upgrade.if you can call it that.... i've thought off puting old ignition back on but hate to keep spilceing the wires. 2nd set of new plugs both sets showed up the same as the ones in it at time of install. front cylinder is ok to lean. more lean than ok back is deffinitly rich.there was no surgeing or difference between plugs before new ignition. i know it's gotta be an easy fix just can't find it. i also agree with proflyer.just hate to mess with the electrical to much haven't had a problem with the ehc yet. nock on wood!!! i'm thinking it's gotta be ignition timeing. i'd take it to a shop but they most don't have anything good to say about big dogs at least the ones ive been in and the harley shops well you know.i went with thunderheart because it's wire for wire can't screw that up...............thanxx for responses does anyone know how to change the timeing on the thunderheart asm5012 useing laptop to advance and retard timeing?????????????
 
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wyatt580

Well-Known Member
called thunderheart gonna send ignition to them to check drivers on ignition. they responded right away i'm happy with that .i'll let you know what they say. thanxx
 
Mickeetwo

Mickeetwo

Guru
mastiffdave said:
My plugs crapped out at Bike blues and BBQ this year. They only had a couple hundred miles on them after a complete going over and a new exhaust at Iron Lightning. The bike was running perfect up untill fri night and then the surging started at about 2500 rpm . Next the bike craps out on 540 , after changing the plugs it runs perfect. The front plug was darn near black and the back one was like its supposed to be. Ive put 750 miles on the new ones and both are like they are supposed tp be. I believe its was just defective plugs cause the new ones with more miles are just fine.
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Glad you found your problem David.....nothing like a easy fix :2thumbs:
 
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