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MAINTENANCE
Suspension Maintenance:
You should periodically check all the moving parts: front and rear end, suspension arms, steering blocks,
steering linkage, shocks, and so on. If any of these should get dirty or bind, then your car’s performance
will suffer.
Motor Maintenance:
Between runs, inspect the brushes to ensure they are moving freely in the brush holder. Do this by
carefully removing the spring and sliding the brush in and out of the holder. If there is any resistance or
rough spots, remove the brush and carefully wipe the brush clean. This will clean off any buildup so the
brush slides smoothly in the brush holder.
After every 1 to 3 runs, remove the brushes from the holders and inspect the tips for wear and/or burning.
If there is a noticeable amount of wear, replace the brushes with a new pair. If the tip is a burnt blue
color, then the lubricant in the brush has been burned away and new brushes should be installed.
When you remove and inspect the brushes, inspect the condition of the motor cummutator also. If the
motor commutator is rough or discolored from the normal, shiny copper color, it may be necessary to cut
the commutator with a motor lathe. Before re-assembling the motor, spray the complete armature and
can with motor cleaner. After completing the cleaning, apply a small amount of lightweight oil to each
bearing for lubrication. Be careful not to apply too much oil, for this will pick up dirt and contaminate the
commutator and brushes.
Differential:
Adjust the differential or “diff” as noted on page 6. Adjusting the diff is not meant to be a tuning option. If
you can hear the diff making a “barking” or “chirping” sound on jump landings, either your diff is set too
loose or your slipper clutch is set too tight. First check your slipper setting, then re-set the diff according
to the instructions on step C-5.
Slipper Clutch:
The assembly instructions give you a base setting for the slipper clutch. The slipper clutch is not
designed to help gain traction on low-grip surfaces. The slipper clutch is intended to relieve some of the
load on the transmission under racing conditions. The slipper clutch should be set so that it has a faint
slipping sound under hard acceleration on very high-grip surfaces. Setting it this way, and leaving it, will
provide the best racing performance.
TUNING AND SETUP TIPS
Camber:
Camber describes the angle at which the tire and wheel rides when looked at from the front or back.
Negative camber means that the tire leans inward at the top.
A good starting camber setting is 1°. A camber gauge of any type is helpful when setting your camber.
Positive camber in the front, where the tire is leaning out, is not recommended. Adding a small amount of
positive camber in the rear will tend to improve straight-line acceleration on loose tracks.
Summary of Contents for BJ4
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