Spark Plugs

Dylan · Trackday Trickster Joined: 03 Feb 2002 Karma :

Ive got an nsr125rk, and got a new spark plug for it. The old one was an NGK BR9ECS. But the one my bike shop gave me for it was an NGK BR7ES. Is one of them for hotter combustioon or summin. They bothe work in the bike. All i want is the best performance, and not the high speed motorway cruizin.

Thanks
Dyl

the_icon · L Plate Warrior Joined: 04 Feb 2002 Karma :

I have exactly the same bike. When my plug needed changing, phoned the local honda dealer and asked if they had any NGK BR9ECS in stock. When I went to collect it he thought I would need two, told him what bike I had and there was a knowing Aahh but no reason given.

I know this hasn't answered your question but the honda dealer suggested I keep to the ECS plug - but don't know why?

I will ask him and see if I can get a better answer.

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

The number is the heat range. The lower number is for cooler running engines and will make them run slightly hotter (spark plugs work properly over a narrow temp range). Use too low a number and the plug will run too hot and be damaged (and possibly burn a hole in the piston), too high a number and the bike will be more inclined to foul the plug, especially at low revs

If you are doing lots of round town mileage then you could consider dropping to an 8, but going down to a 7 sounds a bit risky

All the best

Keith

Dylan · Trackday Trickster Joined: 03 Feb 2002 Karma :

Ill see how hot it gets on the temp gauge and give a report!!!
Dyl

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

At high revs by the time the temp gauge reacts it may be too late. It is not so much water temp that is affected but the combustion chamber temperature. The cooling system should have plenty in reserve.

All the best

Keith

Dylan · Trackday Trickster Joined: 03 Feb 2002 Karma :

Is there any benefit to having a plug that burns hotter. The plug is the one that is recomended in the chart they had in the shop, i might of just had a cooler plug in to start with??? What has everyone else got in there RK's???
Thanks for the reply Keith, you might be saving me a hole in my piston!!!
Dyl

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Honda say a BR9ECS, or a BR10ES for sustained high speed riding.

There is no advantage to having a hotter or colder plug as such, what is required is the plug with the correct heat range for your engine. Basically the difference is the amount of insulation round the centre electrode. Less insulation means more heat is transferred out of the combustion chamber. The pkugs work in a certain temperature range, outside which they will either start to blister and burn, or to foul.

All the best

Keith

Hunter · Nitrous Nuisance Joined: 01 Mar 2002 Karma :

Hey Guys

I have a 92 NSR125RK with an BR9ECS plug, I think that you should stick to this because you can run into all sorts of problems if you go for too low/too high temp ranges!

bye...

N.I.N · L Plate Warrior Joined: 28 Feb 2002 Karma :

I've got a set of NC30 plugs going spare if anyone wants them.