Valve check on an 06 YZ450F

Well, I have about 10 total hours on the bike. 95% of that has been at race speed. I have no issues with the bike other than weeping fork seals. No dings in the tubes just some fine silt dust that gets under the dust covers. A set of seal savers is in my future. The bike is simply phenomenal. I feel it has raised my abilities as a rider considerably. After 32 years of riding bikes, it isn't often that I can say that anymore.

Obsessively, I have changed the oil about every 2 hours of riding time for the first 5 changes. I replaced the oil filter after the first ride and again at the 10th hour. I will probably change oil less often now, most likely at the 4th or 5th hour. There were a couple of times there, that the Yamalube 4R still looked like honey coming out. I have used this break in method with several modern 4 strokes now and simply don't have issues with the motors on my Yamaha's.

On to the point of the post. I decided to check the tolerance on the valves of the beast (06 YZ450F) and my little beast 06 YZ250F. Both were within tolerance. The middle intake on the 450 was right at the limit. I suspect it needs more time to seat a bit better but wouldn't be suprised if it is still there at the limit the next time I check the valves. I have found this to be the case over time myself and I have heard from other Yamaha owners that this will likely be the case. If it becomes hard to start...I'll make some adjustments. As it is, it runs like a scalded ass ape and starts 1st or second kick. I left it as it was and closed it back up. I usually never keep a bike more than 2 years anymore.

I will say getting to the valves on the 450 is a bit of a task. Of course, I removed the seat and tank. I was a bit suprised that I had to removed both motor mounts completely to be able to work the valve cover off. Accessing the rear valve cover bolt was easy with a 5mm t handle allen wrench. I had to use a traditional allen head to get to the front bolt though. Working the cover off is a bit difficult and I had to cut a zip tie and move some cables around to get it off and on again. It is very tight in there!!:ride: Be sure to wash your bike extremely well with the tank off. Wipe the cables throughly. Get everything sparkling making sure to look up under the frame rails as you don't want any dirt in this precious area when the cover is off. You're going to have to manipulate things to get it back together. Also, be very careful putting the gasket back on. Mine bowed out at one point as I was tightening down the rear valve cover bolt. Check carefully in a well lighted area because you just don't want mistakes in this area.

For those who own an 06 YZ250F, the task is much more simple. You don't have to remove any motor mounts. There is alot more room to maneuver the valve cover off.

Anyways, hope that helped some of you and that it will give confidence to other '06 YZ450F owners that Yamaha is still putting out a fantastic product.

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