|The Yamaha AT1MX Replica Project
|Left, at the bottom you see a spacer tube.
This comes in the stock forks and sits on top
of the fork spring. Years ago Webco made a
fork kit for the AT1/CT1, which consisted of a
spring to replace these spacers. Webco isn't
around anymore so we used 3 Briggs and
Stratton valve springs per fork with B&S valve
spring keepers in between each spring &
stacked on top of the stock fork springs.
Finish off with 4 oz. of 20wt fork oil. This setup
will have about a half an inch of preload don't
worry, you'll understand why when it's all
together. The result is a front suspension that
is soft in the first 1 to 2 inches of travel then
gets progressivly stiffer, but is very difficult to
bottom out. This is as good as it gets with 5.5
inches of travel.
|Stock Yamaha spacer tube
|Briggs&Stratton valve springs&keepers
|Slamming into bumps wasn't what made me
nervious about the 30mm forks. Not being able
to hold a line at speed or while cornering were
my main concerns. This used fork brace made
all the difference. The bike holds a line and
turns like a cat on carpet. The 21inch CT1
front wheel Happy found, fit perfectly. Michelin
S12 does the steering well.
|Cycle Gear had the 20wt fork oil, fork seals and locktite.$25
The local lawnmower shop had 6 used Briggs&Stratton valve
springs and 4 keepers. $10 Fork brace on E-bay $15.99 for a
total of $50.99 the AT1 has a front end that works.
|The Before front
end with 18 inch
wheel and no fork
|The used Works Performance shocks were a
bolt on. They were off a CZ and were 13.5
inches eye to eye. The mounts fit well and
only needed the bushings bored out slightly to
fit the larger diameter Yamaha mounting bolts.
A drill and a vise was all that was needed.
The shocks being 1.5 inches longer works out
perfect with the taller front wheel, the bike sits
level and feels good on the track.