2006 yz450f heads

About 5 months ago I picked up a 06 yz450f for a around $1500 and did some basic maintenance (valve adj, wheel bearings, grease linkages) but am planning on tearing the engine down over the winter. I would like to have the valve seats done along with installing steel valves vs Ti and maybee wr cams for a little more added longevity and the wr cams for tamer runing motor. Anyone know a reputable machine shop in the seattle area? Has anyone else done the wr cam swap or is it even possible?



Don't know in he Seattle area, but Millenium Technologies does great work. If you swap to SS valves, you'll also need to use a matching spring/retainer kit.

As far as cams go, the 2007 WR450 cam were the first cams completely unique to the WR. Other cams used in the WR ('03-'06) were nearly identical to YZ cams. YZ cam from '03-'09 and WR cams from from '03-'11 will fit in your bike.

The '07+ WR cams have about 1mm less lift than previous grinds and make really good low end power compared to the YZ cams. I have o set of these cams in a 471 stroker WR. They definately choke off some top end power though, but if you spend a lot of time on tight twisty trails, you'll like the '07 WR cams.

Thanks for the useful info

Definitly dont spend much time in the upper range so 07+ wr cams sound like the way to go.

To get the most from the WR cams, I'd go with a heavier flywheel too.

To get the most from the WR cams, I'd go with a heavier flywheel too.

Already got that portion taken care of. Definitely helped but I still want a little more low end grunt.

Dyna makes a programmable CDI for your bike. I have one on my '06 YZ. Making maps for it was a little tricky. Making a blanket advance down low makes it snappier for sure but the even with the flywheel, it's a handfull in tight situations. I've been playing with advance curves at part throttle settings and have some that work pretty good now, but it was a lot of trial-and-error testing.

You can also try using an FMF Mega Bomb header. Depending on which type of muffler you are using, the Mega Bomb can make a noticable difference. The FMF seems to be the most effective at helping bottem end power when used on a YZ with a quiet muffler. The YZ's really run like poop with a quiet exhaust, considerably worse than with the same muffler on a WR. The Mega-Bomb really works good with the Q4 on the YZ. The stock '06 YZ exhaust is much better, performance wise, than exhausts used on the '07-'09 YZ's.

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