Hello and need some opiions

[gusimus]

Hey Guys, I guess I am the newest member of this group at this exact moment, so wanted to say hello and then get down to business.

First let me make sure that I am in fact posting in accordance to the forums rules...let me know if I need to read anything or do anything etc...

Ok, so now for the opinions thing,...I have been trying out some different spark plugs on my 79' and am getting different results...the question I have is this...
i was using NGK D8EAs as per the manual and then switched out to NGK DREIX8 iridiums, didn't like them so went back to the D8EAs...I found that everything works just as it should with the D8EAs but there is a bit of a lack of oomph as compared to the iridiums (the iridiums caused other issues that I didn't like) i then tried some other plugs for shits and giggles called E3 diamond sparks,,,

The E3s allow for better cold starts a bit more throttle response and a really smooth idle, like really smooth...the issue i am having is this...when I get into the higher rpm range (around 7000 and up) I am getting some backfiring and what feels like a rev limiter kicking in...

This is not happening with the D8EAs....only with the E3s

I am running 900 cams, 900 spark advancer, procom igniters, dyna 3 ohm coils with the bypass relay mod, brand new battery, valves lapped a couple months ago, compression a cool 150 across the board, carbs rebuilt last year and cleaned really thoroughly 3 weeks ago, charging system working fine (all connections cleaned and checked)

I've got stock airbox on the CVs, no leaks anywhere that I can find, and stock main and idle jets (68 and 102)

Is it at all possible that the E3 plugs are needing more gas in the higher throttle position? Would this popping be a lean condition aused by the main jet being a little too small? I was thinking about bumping it up to a 105 to see if that would make a difference.

i can't for the life of me figure out why this is happening, any help would be much appreciated.

Also, the bike seems to be much quieter with the E3 plugs in, like super smooth sounding....

Anyways, thanks in advance for reading...Gus

 

[amc49]

Read more on spark ignition and how the arc develops at plug gap......................

The E3s are telling you what they DO, or f-ck the engine up. I used to sell them for everything, and the number of engines they made 'better' you could count on one hand. MOST they screwed the engine up and it ran perfectly as soon as owner went back to normal plugs. I can tell you why but too lazy to type that much. Suffice to say way more than one reason, gimmick plugs just like the old Splitfire, which was garbage that allowed plug prices to go from $1 a plug to $7+, or ripoff.

I took back in warranty almost every E3 set I sold. I even took one home and put it in a perfectly running lawn mower, the mower then refused to even start, put original OLD plug back in and instant start. Not scientific but good enough for me.

Can't say about the iridiums as they should have been transparent. Neither them or the normal NGK are a good long range plug as they are not double plats at the least.

Did you gap the E3s? (laughing, part of the problem)

 

[madmtnmotors]

I like the Denso X24ESU (now Denso 4099):

http://www.rockauto.com/en/moreinfo.php?pk=261487 (at $1.28 ea you can afford to replace them often)

https://www.amazon.com/Denso-4099-Spark-Plug/dp/B000HCRNZQ (twice the price, but free shipping if you order 15 or more)

These do not come with the screw on terminals. Be sure to remove the screw on terminals from your old plugs if you are using spark plug boots that require the automotive style spark plug posts, or order them here:

https://www.densoproducts.com/Denso-Terminal-Nut-p3450.aspx

 

[dirtdigger]

I always ended up taking the gimmick spark plugs out when customers cam in with running problems when I was a tech. It always seems to me that the farther you stray from factory recommended plugs the more problems you have. All the longer lasting plugs have done is caused an issue with plugs getting froze in the head, long lasting plugs mean they dont need to be changed for 150,000 miles right.......never had plugs stuck in heads when you had to do a tuneups every 30 to 50,000 miles. Most of use dont put enough miles on these bikes to make expensive plugs worth the expense.

 

[amc49]

'It always seems to me that the farther you stray from factory recommended plugs the more problems you have.'

X2. You get the closest matched heat ranges that way. All others are more of a compromise you DON'T need.

Other plugs can work fine but gimmick plugs? Leave them in their pretty boxes!!!! I not only yank them but I throw them as far as I can with the machine owner watching me do it. If that doesn't make the point clear then you can't.

Bosch makes those Platinum +4s and while they work great on the particular Beemers they were specced for, put them in other cars not intended and nothing but problems, yet Bosch pushing ads hard to do so. We warrantied lots of them as well. People just want the new gimmick and until you choke them with it they will not give up. Splitfires? They love them till they hate them ten days later.

I confuse the cars with the bikes, it's absolutely true, you don't want plugs so good they stay in place forever, they will corrode there and damage removing them later. Even the cars can do it now. What good is a 100K plug if it costs you a head change removing it when done?

The iridiums are supposed to be 100K plugs but the iridium is only on the center point, these with waste spark fire two plugs backwards and the iridium needs to be on the wire electrode as well, like double plats or two of your plugs wear a whole lot faster than the other two. I've seen longterm ones where the car owner showed me 4 plugs, 2 looked fine and the other two were missing like half the wire, I had to explain why. Huge gaps there, I was surprised it was even firing. Ford when they first came out with waste spark on cars had the engines running two different spark plugs, one had plat on the center, the other had plat on the wire and about $25 each, needless to say I didn't buy Ford plugs back then. You had to be careful to install proper plug in proper hole too and a pain in the butt.

Run the OEM plug and keep them fresh, you'll do better than almost any gimmick plug out there can do. If you got specialized driving conditions go up or down one heat range to suit, nothing else much to do there other than play with gap to see if you can get it wider, wider if still dependable is better.

 

[madmtnmotors]

The Nippon Denso X24ES is listed in the Honda Shop Manual:

It is a standard copper-core plug. The "U" was added to the part number when they added the "U" groove to the negative electrode.

 

[Dave]

NGK D8EA Yup, yup. Tried others, nothing works better. Some cost more and work the same.

 

[amc49]

Denso plugs are fine for Honda bikes, just harder to find in some locales.

 

[dirtdigger]

NGK and Denso are the only plug brands I will put in any import, car or bike. Had issues in imports using Autolites, champions etc and switch back to NGK and all was well. Did have issues with iridium NGK in two stroke MX bikes though....couldn't keep them from fouling and switch back to the standard plug and all was well. Got to were if a customer brought an import car in with running issue and I saw it had something other then NGK I would swap them out even if they just put new plugs in. Had couple customers complain that they just spent $ on new plugs and I wanted to put new NGK in, fix them though when I did.

 

[amc49]

You just can't go wrong picking the plug an OEM spends probably a million dollars on to guarantee exceptional performance.

Back in the car drag racing days we had plug charts that actually showed heat range on a graph as compared to competitive brands and you could see how they overlay them to try to match other makes but they never fit perfectly. One plug may be slightly too hot and the next step down might be slightly too cold, always a game there. The tip type and how far it extends into the chamber affects heat range too.

Why do E3s suck? The massive outer electrode actually masks flame propagation, screw what the expensive art work shows. All those multiple firing points going on there?, you don't get but ONE spark unless you are running a multispark ignition. Or, highly misleading. The massive electrode also runs cooler because it's so big, so lost performance there, you need a certain amount of heat to ionize the spark path to jump. All electrodes wear by rounding, usually the center rounds since material off of it vaporizes to increase gap over time. These bikes though fire two backwards and rounding at that big electrode can make spark begin to jump from points further away, spark always prefers the sharpest edge to jump away from. A distance increase can make for slight misfires there, ignition generally is more consistent with the firing points not dead exactly the same, rather in a close tight spot. The spark needs to be able to move around from jump off points but only a little, E3 electrode is like every spark jumps from a spot 30 miles away from the last one. Too much space there, that alone allows the tip to be colder. Colder plug fouls easier. They use a cheap crap normal metal center core, like a $1 plug does, nothing special there, what did you pay big money for? Extra wear in an era where plugs pretty much don't wear any longer. Add to that the fact that it's a pain in the butt to regap an E3 to what you want and you got a worthless plug.