Can someone shed some light as to what the references actually mean on spark plugs. I have got a Champion N7YCC in my Rev 3 currently but got a new spare plug which is a NGK BP5ES that I was going to put in at some point. What is best suited for the bike and is there a big difference between them, really?

Edited January 31, 200719 yr by Jetset

Probably many will disagree here but this is the story to the best of my knowledge. The letters vary depending on make except a R at the end means Resistor. If you are not running a radio this should not make a difference. The numbers do not vary from manufacture. They correspond with the heat of the plug. By heat, that only means how quickly the plug reaches operating temp, not how hot the plug runs. I believe a 5 reaches temp quicker than a 7. That is the difference.

Aaron

Edited January 31, 200719 yr by AMiller

Beta's come with a Champion plug in from new but JLI's sell the NGK ones. I've no idea what the numbers and letters mean on either of them. They both do the same job but I think the NGK ones last longer for some reason...

Jetset, the BPR 5ES plugs are better than the champion for rev3,s, stick it in and stay with it

B= 14 x1.25 mm thread

P= Projected tip

R= Resistor Better stick with that for the new digital style ignitions

5= heat range Champions numbers are backwards to NGK's

E= 3/4" thread reach

S= standard tip

The standard NGK has always had a copper core. It dissapates heat faster and gives the plug a broader heat range. With some brands as soon as you get out of the operating range of the plug they foul or cause diasaster. Which is why I like NGK's. They seem to be more tolerant and forgiving.

And to get a little techi. the heat range refers to a plugs ability to disapate heat , not how fast it gets to temp ! Hence to cold a plug will foul easily and to hot a plug can turn a motor into a pinging meltdown waiting to happen !!!!

Glenn

... The numbers do not vary from manufacture.

They do.

For example:

N7YCC = BP7ES

N6YCC = BP8ES

http://www.spark-plugs.co.uk/pages/technical/x-ref.htm

http://www.spark-plugs.co.uk/pages/technical/ngkjpg.htm

I've used NGK bp6es & bp7es on my rev-3's, never had any problems.

Edited February 1, 200719 yr by Tinde

Thanks folks, that has fully answered my question

Thanks folks, that has fully answered my question

Well almost..... Are the BPR5ES or BPR7ES better suited for the Rev 3?

A mate gave me a platinum plug for the rev3 to try yesterday, the bike definitely ran better than before especially low down but not a huge difference, will probably stick with it for a while and see what difference it makes on big climbs.

Well almost..... Are the BPR5ES or BPR7ES better suited for the Rev 3?

Lampkins reccomend a heat five, but I've run a heat 6 in the summer before.

Bob

Anyone tried one of these? Meant to be good but only according to the person selling them.

Iridium Spark Plug

Mate who gave me the Platinum plug has used them before but said the Plats are better, price reflects it as well

Being reluctant to leave something I know works well, the NGK Platinum. I have an iridium in my sherco 125, and has been flawless for months. My sons Sherco 50 went through seveeral standard plugs, and the Iridium lasted quite a while longer.

I use the fine wire platinum/iridium etc stuff in any 2 cycle engines i have: lawn, saws, mc, etc. Last longer, start easier, less fouling. 3 to 5x the money, and I think well worth it.

The functional advantage is in the fire wire design-It takes less voltage to initiate the ionization and spark jump across the gap with a sharp small point than a wide flat or rounded surface.

The reason for the fancy metal is that the conventional nickel iron center wire would overheat and melt if made into a fine wire, not enough mass to dissipate the heat rapidly. (This local heat is a totally separate issue than the heat range of the tip and insulator)

The basic idea was known many decades ago. I saw a tip in literature written in the 20's about filing to a point to prevent oil fouling in auto engines of the model T era. The idea was there, just not have the materials to make it last until the last 20 years or so.

Freshly filed ground electrodes and sharp flat center electrode of conventional plug improves spark, same reasons. just not last so long until it rounds off.

I'd recommend trying them.

kcj