Spark Plugs: Too much choice!

[Slingshot]

I've decided I need to change the plugs in the CBR, it's missing heaps when it's cold and not starting as well as it use to. So my question is this:

What type of plug should I replace the existing ones with, Denso, NGK, Champion, Spitfire etc and should I go standard or something special like Iridium or Platinum.

I'd also be interested to hear from anyone that has ordered off the net, any recommendations?

Cheers John

[vifferman]

Stick with NGK. I've tried the Iridium ones (they didn't have the 'ornery' ones in stock, and the Iridium ones were only marginally dearer), but didn't notice any difference. Note that "missing heaps when it's cold and not starting as well as it use to" may be due to things other than just the SpockPloogs, such as other ignition problems, a tune-up being needed, crap in the fuel bowls, air leaks, etc. etc. Having said that, new plugs won't hurt, unless you replace them and the new ones get fouled (assuming fouling's an issue).

[TwoSeven]

Stay with NGK, apart from the bike being designed for them (along with denso which are generally unreliable), you may want to try putting either the correct temp plug in or the proper fuel :)

[Slingshot]

Cheers Vifferman...I thought I'd start with the plugs and if that didn't help I'd move onto other things. I'm not sure if the plugs have ever been changed, I do know they haven't been done in the 12000ks that I've had the bike.
I'm going to try and find the fuel filter and give that a clean and will look to replace the air filter as well.

I'm not to keen on pulling the carbs apart to give them a clean out...I'd hate to make them worse :)

The battery was flat this morning as well...arrgggg.


How much should I expect to pay for the plugs?

[Slingshot]

you may want to try putting either the correct temp plug in or the proper fuel :)

I assume the owners manual will show the correct temp plug to put in...and as far as fuel goes, I use 96 so I guess that's proper.

[vifferman]

How much should I expect to pay for the plugs?
About 5 or 6 times what you think is reasonable. I think the Iridium NGKs for the VTR were $27 each.:eek5:

[Motu]

Stick to the standard plugs,NGK or Denso...I prefer Denso.It's possible the change of plugs may make it run better - and so disguise the real problem,until it rears it's ugly head again later....

[XTC]

The battery was flat this morning as well...arrgggg.


Has the bike been sitting? Is the battery old? If no to both these questions then get your charging system checked. Honda Reg/recs have a habit of failing. this causes the battery to overcharge and fail. If left too long it can also damage the stator. It's a quick and easy job to check the charging voltage when the bike is running. If you notice that your warning lights are getting dimmer during a ride or that your bike winds over slowly when hot (or not at all) then this points to the reg/rec failing. If not then all should be fine. Get a new battery if yours is not holding a charge.

[Slingshot]

About 5 or 6 times what you think is reasonable. I think the Iridium NGKs for the VTR were $27 each.:eek5:


At least you only need two of them!

[Slingshot]

Has the bike been sitting? Is the battery old? If no to both these questions then get your charging system checked. Honda Reg/recs have a habit of failing. this causes the battery to overcharge and fail. If left too long it can also damage the stator. It's a quick and easy job to check the charging voltage when the bike is running. If you notice that your warning lights are getting dimmer during a ride or that your bike winds over slowly when hot (or not at all) then this points to the reg/rec failing. If not then all should be fine. Get a new battery if yours is not holding a charge.


I commute into the city every day, I didn't ride the bike on Sunday or yesterday though. The warning lights don't dim while riding and when it's hot it starts no problem at all.
A while back I had the same problem with the battery going flat, I hadn't been on any decent rides and had only been commuting on it for a while...it's probably just not getting a long enough blat to keep the battery well topped up. I was too cheap to replace the battery back then but took it on some decent rides...problem disapeared...sounds like a good excuse for a ride to me:yes: .
If I put a multimeter across the battery while the bike's running, what voltage should I expect to see?

[Slingshot]

Stick to the standard plugs,NGK or Denso...I prefer Denso.It's possible the change of plugs may make it run better - and so disguise the real problem,until it rears it's ugly head again later....

Good point Motu, perhaps I should give it a bit of a service.


Replace spark plugs
Clean/Replace air filter
Clean/Replace fuel filter
Oil Change (can someone suggest a good oil to use?)
Clean the carbs (can I just spray something into the airbox or should I strip em down and clean em properly?)
Check/replace the spark plug leads.
Check the plug caps are still securely fitted
Is there anything else I need to look for and is it worth putting one of the additives in the fuel to clean the system out, how about an additive for the oil before the oil change, is this worth doing?

[vifferman]

If I put a multimeter across the battery while the bike's running, what voltage should I expect to see?
It should read between 12 and 13 volts at rest (engine off) and when it's running, the voltage should increase to about 14-ish (varies) at 5K rpm. If you turn the lights on (or the brake light, if your lights are on all the time), the voltage should dip momentarily, then go back to what it was reading.
If the voltage doesn't increase with revs, increases too much (over 15V), fluctuates wildly, or increases slightly then goes down, the R/R and/or battery are suspect.
R/Rs can, but don't usually cark it in such a way as to cook your battery. Most commonly the battery will go flat because the R/R isn't letting enough volts through. The R/R is Regulating (controlling voltage output) and Rectifying (converting AC to DC) - either function or both can fail.\

Fuel additives are often a waste of time, and oil additives definitely are. If your carb has problems with 'varnish', then fuel system cleaners might help to clean them out, but it's more effective to clean the carbs manually. Use a good oil (I like Motul 5100 semi-synthetic, but any 'reputable' oil will do) and it will already have the right additives. If you want, you could buy some el-cheapo oil, warm your bike up, drain the oil, put the cheap oil in, warm it up again, then drain it again, but it's probably not going to make any noticeable difference.

[Slingshot]

I've now ordered the plugs.

I'm getting them from super cheap auto at $15.99 each instead of the $24.95 that was quoted by a local bike shop.