Hey all,
I ordered NGK DPR8EA-9 plugs from Ebay (used a cross-reference chart I found) and noticed on the NGK site that they have model # DPR9EA-9 instead. Anyone know the difference. The chart I used had up to 1994 models using DPR9EA-9 and from 95-96 using DPR8EA-9's. Know I'm wondering if i should use the ones I ordered or go get the DPR9EA-9's instead? They have the same specs as far as I can see.

BTW, after reading previous posts, any other suggestions on idle not being kept unless the choke is on?? Could old gas (about 8 months/ last season) and original plugs (5300 miles on her!!) be the culprit?

Thanks
Phil

 

Well 5300 miles is not much on plugs. I have 12K + on the plugs in mine and they still look like new.
I would suspect that it's not so much the old gas in the tank, but rather what the gas sitting in your carbs has done. Like plug up some jets.
Grap a can or two of fuel injection cleaner, drain the tank and put new gas with the FI cleaner in it and run a couple of tanks through. If it hasn't cleared up, then you'll have to pull the carbs and take them apart to clean them out.
BTW next winter try some Sta-bil in the tank. Works great for winterizing a bike. Or... just ride year round!

 

The difference between #8 and #9 plug is that the #8 plus i warmer. It gets warmer which helps to maintain the plug free from rich-fouling, but can overheat if the engine is used at maximum power. I have seen that the #8 plugs was specified as an option to #9 plugs, i believe it is in the Haynes manual. I think you can use the #8 plugs without any problems if you are just commuting with the bike and not run very hard. If you know you will go full power from time to time, go for the #9 already from the beginning, they are reasonable cheep after all and a melted side electrode on #8 plugs can be costly if the tip burns off and comes free in the combustion chamber. However, what could be more likely to happen with the #8 plugs, rather than a plug failure, is that they can begin to glow if used at full power. That could if happened, cause unwanted preignitons/detonations which can kill the engine in fractions of a second in worts case. A motocycle engine is not as rugged as a large old iron V8, or a truck diesel, so there is less room for any errors.

 

Thanks for the information guys, never having drain the tank, is there an easy way of doing it?
Hopefully it will clear up the jets by running some fresh gas and FI cleaner inside.

Thanks again!

 

R1000,
I rarely use it a full power, the most on average I'll go up to is around 8,000 rpm's.
I use it to go cruising mostly with some of my pals, that's about it, nothing hard core.
So, I guess I could use the new plugs along with fresh gasoline and see what happens, the worst case would be for me to spend another $13 on plugs and whatever it costs to clean out the carbs.

Phil

 

No problems to use a plug one step warmer with a sensible driving like you describe. I used the recommended #9 when the bike was ridden quite hard between 8,000 to 10,000 + rpm during 20 minutes per session on track this sunday. I did 4.5 sessions, stopped after 10 minutes in the last session due to overheated rear tyre which began to slide.

A reference from the car world that would give you an idea of the scale:

# 6 plugs @ stock but powerful V8 with a few houndred horsepower
# 7 plugs @ 500 horsepower, occasionally with nitrous
# 8 plugs @ 1000 horsepower with nitrous
# 9 plugs @ 1500 horsepower with nitrous

The CBR has plenty more hp/litre than a stock V8, which motivates the plugs to be #9 to also cover hard driving.

Edit: The hotter Suzuki GSX R1000 with about 170 hp per litre also uses #9 plugs. And the wird spelling error horepower is fixed [X(]

 

Freudian slip. I use the DP9EA-9 plugs. They have no R (resistor). I also took out the little resistor in each spark plug cap, and inserted a screw. With both resistors gone, one supposedly gets a hotter, but shorter-lasting spark. It seems to start easier.

 

When coming to some basic specifications www.louis.de have a nice little "MotoBase"..

http://www.louis.de/_3031919b067bcea...ONTENT=auswahl



DPR9EA-9 for my bike.

 

That's cheeting, to use specifications and manuals [:@]. Seriously, a very good link, thanks !