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simimi

YZ400 spark plug change tips please

11 posts in this topic

Hi all,

Is there a special tool or procedure for changing the plug on my 98 YZ400?

I have run it for several years with the same plug, probably should change it, just in case,

thanks

Mike

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i have the 99 yz400 if its the same as mine, im sure it is, just take off the gas tank , pop off the spark plug boot ....all you need is your 5/8ths spark plug socket, an extension and your socket wrench, the spark plug is a ways down in the valve casing so thats why you need the extension for your rachet..... loosen it up and pull it out, put the new one in, be carefull not to cross thread when tightning up the new plug...and watch out for mud and dirt it can build up in the spark plug housing if your cap is not on tight.......clean all that out........and you can even apply spark plug protector(buy at the store) to keep the boot and plug from rusting for the next time and allow for easy removal....

thats it........

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Just a little suggestion about getting new plugs... I've found that Advance Auto Parts will usually order you a plug [or 4] and they are typcially 50% of what the dealer charges. I've gotten my plugs from Advance Auto Parts for the past 4 years now. Saved quite a sum of money... and just found out... the plugs come with a 1 or 2 year warranty [depends on the type you purchase]. Example: Standard NGK CR8E [my 426 uses] approx $2 w/1yr warranty, Iridium NGK approx $6 [latest thing since platnium] w/2yr warranty.

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Just a little suggestion about getting new plugs... I've found that Advance Auto Parts will usually order you a plug [or 4] and they are typcially 50% of what the dealer charges. I've gotten my plugs from Advance Auto Parts for the past 4 years now. Saved quite a sum of money... and just found out... the plugs come with a 1 or 2 year warranty [depends on the type you purchase]. Example: Standard NGK CR8E [my 426 uses] approx $2 w/1yr warranty, Iridium NGK approx $6 [latest thing since platnium] w/2yr warranty.

Wow, i'm coming to live in the US!!! Over here, stock NGK CR8E's are about $10-12, and CR8EIV's (Iridium's) are $18-20. :)

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Thanks again for the great info. I found the NGk plug, and the Iridium listing as CR8EIX , but could not locate the CRE8G as you mentioned above.

Also, the last plug has lasted since I bought the bike, 4 years ago. Any reason to upgrade to the iridium if what is in there has worked so well?

I run the FMF Q pipe, and bike starts on 3 kicks cold, 1 kick hot. I usually do not need to run the hot start button unless it is a hot day.

thanks

Mike

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a 3/8 universal or wobble swivel would'nt hurt. it makes it alot easier to get the plug in and out, as the backbone of the frame is partially overtop of the plug hole. take your time, i also used compressed air to blow anything out of the recessed cavity where the plug is. i just got mine a couple months ago, i am still working out the bugs, but if you paid less than 2 grand for it, than you have some room to work with. at least that's my opinion. lol

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Motion Pro makes a neat little combination plug socket and extension for these that can be used on 450's and 250F's with the tank on (barely). Might not work with a 400/426.

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Don't know if just any plug wrench and extension will work, the bike should have come with a pivoting plug wrench. If you purchased your bike used and you didn't get the wrench, you can pick them at your local Yamy dealer for around $15. It makes the process a whole lot easier.

MThumper

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OOPS! I just got back to this thread and saw my boo boo that should have been a CR8EK sorry :)

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