Newbie questions

Good morning all , just got this bike on a trade, was told it was an '07 yz450f, and under further checking the 10th digit shows more likely to be an '06 ?

as my 10 digit is a 6,  but why are there 07 possibiilities, due to late year builds ?


There are 4 possible matches. Year Make Model VIN    

  2007 Yamaha YZ450FWL


JYACJ10C47A012968 Parts Manuals Specifications CycleChex

2007 Yamaha YZ450FWW WHITE/SILVER JYACJ10C47A012968 Parts Manuals Specifications CycleChex

2006 Yamaha YZ450FSPV 50TH ANNIVERSARY EDITION YELLOW/BLACK JYACJ10C16A000131 Parts Manuals Specifications CycleChex



i know its not a yellow black...


concerned about the loudness, i pulled the valve cover this morning to check cam chain tension which was ok, so im going to change plug while in there, and i pulled out a 9 instead of an 8, which manual shows for an '06, what issue would a hotter plug cause ?? also is an iridium better , worth the extra $ or not ?


thanks in advance

Edited by wetneck

Pretty much everywhere but the US, the larger number plug is colder.  An NGK CR9E (or EIX) is colder than a CR8E(IX).  Probably wouldn't be able to keep it from fouling except in hot weather or when used only for long riding periods.  If the plug color looks dark, go back to the CR8E. 


If you ran your VIN through a parts warehouse, that's why it came back with so many matches; their records are a jumble, usually.  If the tenth digit is a 7, it's an '07.  

Yea i put an 8 back in yesterday and i already assumed an 06, thanks for the reply !

What in your best guess, was the previous owner trying to accomplish by going with a colder plug ?

The bike was/is in Fl, humidity capital and zero elevation. ....

He probably thought it would make the engine run colder.  That's a fairly common misconception.  In fact, of course, the heat range of the plug refers only to how hot the plug itself runs, and that's a matter of keeping the plug hot enough to burn itself clean, but not so hot it causes preignition or damages itself.  Doesn't have an effect on engine heat in any direct way.

Ok undetstood on the plug

Is it safe to run a product like seafoam thru motor to clean or not recommended?

I have an exhaust leak at pipe/silencer joint and ordered new gaskets for front and back, but the clamp appears to not clamp perfectly round, is that normal?

Im new to 4strokes and appreciate all the help.

I would rather just run clean oil through the engine if the inside seems dirty.  Get something good but cheap, like Rotella, run it for one ride and change it.  Do that a couple of times and switch to whatever your favorite flavor is.


If you're using the stock pipe, you'd need a gasket and a clamp.  Almost all aftermarket pipes are slip joint; no gasket or clamp.  And yeah, the clamps won't quite do a perfect circle on their own, no big deal, usually.

Actually i meant for the fuel side, carb specific, we use it in outboard motors often

Another question, waiting for the gasket between pipe and silencer, #13, why would they make the gap so large, and do the aftermarket pipes use the same gasket,have the large gap ??

And what different years will fit my '06 ??

Aftermarket pipes do not generally use a gasket; just a slip fit.


.06 -'09 are direct fits, but you do not want anything to do with the '08-'09 systems.  Poor performance.

ok , new exhaust gaskets here,front is easy enough but the pipe splice still sucks, leaks when i blow back thru silencer. how tight should i expect it to get ? i read that leaks can cause popping/backfiring, which i have some, i guess im trying to get it airtight ??


and which orientation does the gasket go in, the mesh side in or out , as in the manual it really doesnt show

when i pulled out the old one the mesh was towards the front, as i pulled on it.

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