Project Foo Fighter: 2007 Yamaha XT225 Build, Part 4

Jul. 21, 2010 By Dan Paris

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Action photos by John Grant, Ryan Rainville and Lawrence Hacking

In the last installment of Project Foo Fighter, our little XT225 project bike was awaiting some suspension work. That’s been done, but it remains to some degree a work in progress. As always, the faster you go the more problem areas become apparent. In the great spirit of blowing right on past the point of diminishing returns, here’s part four of project Foo Fighter!

To review, follow the entire build here:

Project Foo Fighter, Part 1

Project Foo Fighter, Part 2

Project Foo Fighter, Part 3

The first time we rode the Foo Fighter with modified suspension was at the local motocross track. It was a huge improvement at both ends, but the rear was still a little light on rebound damping.

The forks were the weakest part of the XT225 suspension package. Not as sophisticated as a decent mountain bike, the damper-rod style 35mm forks also coughed up their mushy travel with spring rates more appropriate to a bicycle. We started with the installation of Race Tech Emulators, which basically attempt to mimic the action of more modern forks and offer a degree of adjustability.

The technicians at Cycle Improvements/MX-Tech modified the damper rods to suit the Emulators. They also polished all the internals for smoother action.

With the forks stiffened by the addition of .46mm/Kg straight-rate fork springs, we now had a more controlled, though still spindly, front end.

The shock was grossly under-damped and under-sprung for any sort of aggressive riding. The first step to making the rear end of the Foo Fighter behave for an aggressive 170-pound expert trail rider was installing an appropriate 6.8mm/Kg shock spring.

We guessed at the valving for the first trial run of the modified shock, going up substantially on high and low speed compression and rebound damping. With the bleeder nuts, the rebound damping adjuster was now completely independent of the compression circuits, making trackside tuning easier and more effective.

Despite the short wheel travel, with the stiffer suspension we could actually jump the XT a little bit without fear of breaking the bike in half. On the trail, the bike soaked up small impacts just as nicely as it ever did, meaning cushy! After our test run, the shock was removed and sent back for more valving modifications to the rebound circuit, but we were close!

We got the shock back the same day the bike was scheduled to be trucked to Alberta for rounds one and two of the Canadian Enduro Championship, where I’d be using it as a mule for photographing the races. Aside from being a capable workhorse, the bike spent 10 days trail riding in Canada’s Rocky Mountains with riders on much more serious machinery.

For an East Coast boy, used to swamps and forests, playing in the snow in July was just too much fun! Getting back down those mountains was another matter. On some long downhill trails we had to stop and adjust the rear drum brake several times. Often we’d be on the front brake so hard the skinny forks would twist in the clamps and on the axle. Not good.