After the last run I noticed my transmission wasn't working so
well in reverse. I didn't find any chunks of clutch material in the pan so I
decided to try adjusting the reverse band. There are two different reverse
band adjustment procedures for the TF904 and I am starting to suspect mine was
setup to the wrong one. One version has you tightening the band to a
specific torque, then backing off 7 turns, while the other setup requires 4
turns. My particular band tensioner was about 6 turns looser than what it
should have been.
The last run also convinced me I needed to move the radiator
up so it would not blow hot air on the fuel cell. While some of my customers
have gotten away with running a 4 cylinder radiator down low I just could not
keep the rear tubing from creating a hot zone around the cell with all the heat
coming off my 26 x 19 dual pass radiator. I had designed the chassis with this
possibility in mind so I just needed new mounting brackets. I opted for
adjustability so I came up with a cradle that is spaced off of 4 tabs. I
can adjust the height of the radiator by changing the spacer lengths.
The upper hold down was made from two pieces of sheet metal,
this front piece has two bends in it while the piece forming the back section
has a single 90 degree bend and is welded to the front piece.
Here is the painted up bracket with both front and rear tabs
I really need to learn to weld aluminum. The lower
cradle would be nearly half the weight if I had made it from aluminum. I
tried to put ample lightening holes to cut the weight as much as possible.
After applying so rubber strips to the lower cradle and upper
hold down I bolted everything back together. I left a few inches of
clearance between the roof and radiator to allow for chassis movement in a roll.
My transmission cooler also needed to be relocated to avoid
blowing hot air in the vicinity of the fuel cell. The simplest solution was a
pair of tabs that bolted to the original mounting points, The lower end of
the bas were bent at a 30 degree angle to direct the air up and away from the
This change has left a large open area behind the rear seat
which I intended to wall off and use for storage.
The storage cubby behind the rear seat ended up being formed
from 3 pieces of aluminum which were then riveted together to form an 8 inch
deep rectangular pocket. It should come in handy this winter for jacket/headset
storage once we reach the trail.
Something I meant to do but never got around to was to box in
the front upper link mounts on the chassis side. the passenger side mount was
actually bent inward so it took a while to get it straightened out not to
mention the 5/8 bolt was bent in the middle. I think the tabs may have been bent
when I slammed the front end back down after doing a massive wheelie at
the Hammers. I know for sure the front shock mount was bent on the
passenger side after that little incident.
On the test run the new radiator position worked much better
once I got the system burped of air bubbles. For most of the crawling and fire
road driving the temps stayed at 160-180F with only one fan on. Previously the
single fan could hold it around 200F while crawling but I needed the second fan
on if I was doing any sort of speeds on road. The fuel pump stayed totally
silent the whole trip and the fuel cell stayed around the ambient air