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Best Spark Plug to use in WR450F '2011


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Hi !

 

I want to change the stock spark plug, I made the free mods, and I have a new complete FMF exhaust system, and boyesen quickshot 3, Jd Jetting Kit....

 

I read something about the NGK spark plug of Iridium is better than original

 

now I need know the reference and place to buy one...

 

thanks for help and opinions...

 

 

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Ok thanks! So there isn't any proven plugs for easier start on kickstarts only?

yes there is. its the heat range of the plug. depending on what kind of riding you do will depend on the heat range of the plug. if its very stop start technical riding using not a great deal of throttle you will use a hotter plug,if its wide open throttle such as supermoto or motocross you will use a colder plug. i switched to a cr9e in my yz426 because i was riding in very technical trails at not much more than half throttle. it definatlely made starting a bit easier. its all in the service manual

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yes there is. its the heat range of the plug. depending on what kind of riding you do will depend on the heat range of the plug. if its very stop start technical riding using not a great deal of throttle you will use a hotter plug,if its wide open throttle such as supermoto or motocross you will use a colder plug. i switched to a cr9e in my yz426 because i was riding in very technical trails at not much more than half throttle. it definatlely made starting a bit easier. its all in the service manual

 

 

So, you went to a CR9E plug from the std CR8E contradicting your own advice :bonk:

A CR9E is a colder plug than an CR8E

Your easier starting probably came from the new plug rather than the heat range change

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my apologies,i must have got the numbers the wrong way around,my bike has been sitting in the shed for 10 years so its 10 years since i last changed the plug. i definitely remember it made a difference as i used the hot start less. just google spark plug heat range yz426 or wr426 and you will find a wealth of information

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Heat range of a spark plug is about removing heat from the insulator around the spark element

It does not change the heat of the combustion.

It changes the heat of the metal in the head, which dissapates either slowly or quickly.

If the motor is not burning all its fuel quickly enough, you put in a hotter plug to assist this

If the motor is pre-igniting it's fuel, you put in a colder plug

You determine this by analyzing the exhaust for un-burnt fuel, or aluminum particles (pre-ignition)

 

Changing heat range for any other reason is purely 'emotional'.

 

On a low compression, low-flow head like the WR, changing to anything but the stock plug will make it run worse.

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