On this week’s 4-Stroke Project Spotlight the main focus is our 2018 Yamaha YZ450F motocross project with long-time test rider Pete “Grandpa” Murray. It’s pretty amazing how drastically different our Yamaha looked and performed after the changes we made. This week’s Thumper Theater features a nitromethane burning hillclimb machine, 2019 Yamaha YZ450F in the raw and a couple project bikes you don’t won’t miss. Check out the exclusive link to a clean Honda CRF450R built with lots of help from Pro Circuit at the bottom of this post.

As you can see we went a little bold with this Yamaha YZF build. The Polisport Flow Yellow kit and Red Label semi-custom race graphics definitely make this machine pop.

Dubach Racing Development engine relocation kit moves the 2018 Yamaha YZ450F engine forward 1.5mm and is designed to improve front-end traction. Internally the engine is stock but the throttle body was modified by Injectioneering

We used the new Torc1 Defy lock-on grip for four-stroke applications that have a “Tacky” texture.

Dubya USA laced up a set of silver Talon billet hubs to some black DID Dirt Star rims with some custom black stainless steel spokes accented with silver spoke nipples. Talon sprockets, a Regina chain and an IRC M5B transferred all that Yamaha power to the ground.  The blue chain adjustment blocks and rim lock hardware are part of a Dubya Bling kit.

The seat is slightly taller that the 2018 stock unit and is available from GYTR.

The Ride Engineering handlebar clamp is 5mm lower than the 2018 stock units and the same height as the 2017 YZ450F model.

The Dubach Racing Development complete stainless steel and aluminum system saves some weight and provides a nice performance increase across the board. This system is also equipped with a removable forestry service approved spark arrestor.

To improve stopping power we installed Galfer rotors and silver steel braided lines all around.

Although our Dubya USA Yamaha YZ450F looks drastically different  the real shock value for us was how well it performed by making a few targeted changes. For the complete “Project Grandpa” story check out the July issue of Dirt Bike Magazine.


If you liked this week’s 4-Stroke Project Spotlight check out this sweet Honda CRF450R build we did with Pro Circuit. Click the image below! 

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