Yz450f header pipe on 2010 wr450f

[Cooneyjj]

My 2010 wr450f has a gytr muffler with the stock header pipe which requires a slip on insert to fit the two together, I want to eliminate the slip on insert. I've heard the yz's hear pipes are bigger therefore it's a flush fit between muffler and header. Can any one confirm this for me ? Cheers !

[FORMA MOTO]

You are correct

[SteveThe Snakes]

The 08 and 09 Yz450 have the largest head pipe. They fit in a FMF rear tail section without a spacer not sure about the GYTR unless it's the same as a FMF.

[Cooneyjj]

Ok sweet thanks

[SilvFx]

Cooney...dont make the assumption that the YZ450F headpipe will make it run better.  I owned an '08 YZ450F and the low end is lacking a bit (compared to the WR) partially due to the size of the head pipe.  So, while it may look cleaner to no have the FMF insert/spacer it may make take away some low end grunt on your WR.

 

So....i wouldnt spend alot for a YZ head pipe for your experiment.

[Cooneyjj]

Cheers slivfx ! I wasn't to concerned power wise as I've had the wr rejetted but yer I'll still take that in to consideration ! I am trying to find a Second hand header pipe but there none around cheap enough !

[SteveThe Snakes]

Um not sure about losing low end with that header pipe. I run them on all of the WR's. But they are pricey.

[Cooneyjj]

Yer my wr cracks pretty hard since the rejetting ! But yes that's the main reason I haven't gone and got one because there bloody expensive ! My old mans 2012 wr450f header fits perfect with the gytr slip on muffler but there $340aud !