Topic: NGK D8EA vs D9EA

[Johnie]

What is the difference between the 2 plugs? Just the heat range? The reason I ask is I got a box of 10 D9EA for $10 before I realized I have been using the D8EA. Can I run the 9's in the CB750 or would I expect problems.

[Grey]

They are the next stage colder plug. Good for hot weather or running hard for the most part. Stick a set in. If they don't foul then your good to go. If you know someone with a modified motor sell the plugs to them.

[grcamna2]

The D8EA are stock plugs for you're CB750..D9EA's are one step colder for running it flat out..or w/ aftermarket high energy coils.

[Gordon]

They're one step colder than the stock plugs and will tend to foul out under regular street use. 

[Kevin D]

Johnie  - not that you are asking, but I followed a Hondaman tip and have been happy with my Denso's:

http://www.sparkplugs.com/results_appOther.asp?otherMotiveID=58433&mfid=3

I have a coffee can full of slightly fouled NGK's, just one set of Densos for, I dont know, 3-4 years maybe 10000? miles

[octagon]

another vote for densos.
this is a little slack, but i found a set in good shape in a parts bike, and did a search and found hondaman's recommendation. noticeable improvement, and i've been running them for almost a year. pulled them recently and they look good, and the bike is running good. the parts bike last ran in the early 90's.

[grcamna2]

I've always had good life & performance from NGK's...as long as the jetting is "on" and it isn't burning oil or trying to run stale fuel..those NGK's last for the standard duration.
I may try a set of ND's for my next time and do a comparison.

[HondaMan]

What is the difference between the 2 plugs? Just the heat range? The reason I ask is I got a box of 10 D9EA for $10 before I realized I have been using the D8EA. Can I run the 9's in the CB750 or would I expect problems.

If you hit the highway with a 17T countersprocket and run 80+ MPH, they will be spot-on heat range for the run. That's how you can travel 100 MPH for 1000 mile back-to-back days, for weeks on end.

For anything else, they are too cold. Try using Shell gas, regular grade, to help keep them clean in normal riding.

[phil71]

I put the ngk precious metal plugs in my K1 and was very happy with the gain in throttle response and overall crispness... Though , at puttering speeds they load up a little.

[Johnie]

I have had excellent performance with the NGK D8EA in every bike so hate to put these in. I may just take these 9's and exchange them for some more D8EA. I could say it was a gift and no receipt at the local store. Maybe they will do the exchange for me. I actually found these at a liquidation sale. Figured $1 a plug is a good deal.

[ekpent]

I have had excellent performance with the NGK D8EA in every bike so hate to put these in. I may just take these 9's and exchange them for some more D8EA. I could say it was a gift and no receipt at the local store. Maybe they will do the exchange for me. I actually found these at a liquidation sale. Figured $1 a plug is a good deal.

For some reason I just don't see you doing that Johnie. I think before you were done you would be shaking,asking the store to call the police and confessing your sins for all to hear and begging to be taken away.     

[grcamna2]

A sohc4 forum member w/ Hot coils can use that heat range as standard plugs..just offer them up for sale here for.... $1.50 per plug.

[john_matrix]

Ok, I have a stupid question:

I just ordered the Denso plugs. You don't need to gap these before you put them in, do you?

Stock bike here.

[LesterPiglet]

It would be a good idea to check them and then decide.

[bwaller]

Johnie, I use D9's in my race bike, I'll buy them if you haven't done anything with them yet. Too bad though I just bought a bunch.

PM away.

[grumpy]

FWIW
The Densos are a touch too hot for my K3. The D8eas work better - but 95% of my driving is on the freeway at 5,000+ RPM.