Yerf-Dog 31700, Owner'S Manual, Page: 11 / 16

11
Engine Lubrication – You must change the oil in the crankcase after the first two hours of operating your
new engine and after each 25 hours of use thereafter. That will insure proper lubrication in internal parts
and prevent costly repairs due to excessive wear. Refer to Engine Maintenance Instructions.
Chain Lubrication (Clutch and Drive Chain) – For the best chain life, it should be lubricated with a
graphite type of lubricant such as the spray-on type which evaporates leaving the graphite on the
chain. Using oil or grease on the chain in dusty or sandy riding conditions may cause dirt particles to stick
to the chain resulting in rapid wear from abrasion.
Clutch Lubrication – There are two main elements that can shorten the life
of a clutch – poor lubrication and dirt/sand. The Centrifugal Clutch (14)
contains an oil-impregnated bronze bushing. It is press fitted on the
sprocket and surrounds a steel sleeve onto which a snap ring clips. The
small Snap Ring at the end of the Sprocket holds the clutch together, and
for this reason the snap ring should not be removed. With the engine off,
apply (4 or 5 Drops) of oil (SAE 30 motor oil) to the Snap Ring area, try to
manually roll the mini-bike along while applying the oil. If you lift the rear
end and support it on the frame you can rotate the rear wheel to work the
oil into the bushing. Never apply grease to this bushing, because it will
clog the pores and retard proper lubrication. For best results, oil every two
hours of running time.
SAE 30
Motor Oil
(4 or 5 Drops)
Centrifugal
Clutch
Snap Ring
Brake
Band
Brake
Drum
Brake
Cable
Adjuster
Nut Locking
Nut
BRAKE
ASSEMBLY
Brake Test – Always do a brake test before
operating vehicle. To test brake function:
Sit on the vehicle with the brake actuated, grip and
squeeze the Brake Lever (12). Have an assistant
push the vehicle forward. If the rear wheel turns,
the Brake needs to be adjusted. Do not operate
this vehicle unless the brake is properly
adjusted and working.
Frame
Pin
ADJUSTMENT INSTRUCTIONS
10
11
9
14
Sprocket
Pad
2. Tighten Brake Band (9):
-Loosen the Locking Nut on the Brake Cable (10).
-Turn the Adjuster Nut counterclockwise to
tighten the Brake Band on the Brake Drum (11).
-Tighten the Locking Nut.
3. Check the Brake Lever (12) for Reach Distance,
so the Brake Lever is comfortable for the rider,
and for Minimum Clearance when fully actuated,
the Brake Lever must have no less than 1/2”
clearance.
To change the Reach Distance:
-Turn the Reach Adjuster Screw.
To change the Clearance:
-Turn the Clearance Adjuster.
-Retighten the Locking Nut.
4. Test brake function - see Brake Test.
1/2 Inch Min.
Clearance
Brake
Lever
Clearance
Adjuster
12
Locking
Nut
Brake
Cable
10
BRAKE LEVER
Reach Adjuster
Screw
Grip
26
Reach
Distance
Brake Adjustment – Always test brake before
and after adjusting - see Brake Test .
To adjust the Brake:
1. Check the Pad thickness on the Brake Band (9).
Make sure the Pad is not excessively worn. If
excessively worn, less than 1/16 inch of Pad
remaining, replace the Brake Band.