Curtis KUBOTA B2650 Operating instructions

INSTALLATION & OWNER’S MANUAL
Rev. D, p. 1 of 12
The contents of this envelope are the property of the owner.
Be sure to leave with the owner when installation is complete.
KUBOTA B2650/3350
Hard Sided Cab p/n 1KB33AS
Soft Sided Cab p/n 1KB33SS
Installation Instructions
APPROXIMATE INSTALLATION TIME: 2 to 3 HOURS
(excluding accessories)
Hard sided cab shown with optional work lights, and optional strobe light.
Additional options available are: heater, hard rear panel, and rear window wiper.
Note: a front windshield wiper comes standard with this cab kit.
p/n: IM-1KB33
Revised on: 12-1-2015
Note: photos for illustration purposes only.
Colors and features may vary.

DESIGN CONCEPT
Curtis cabs feature an assembly of parts designed for your vehicle which require
adjustment and alignment of components to accommodate vehicle variations and
provide proper weather protection. For accurate installation, proper operation, and
years of satisfaction, please read and understand the installation instructions.
From all of us at Curtis, we thank you for choosing our product.
CAB INSTALLATION
BEFORE YOU START
HELPFUL HINTS:
A. Refer to parts diagram toward the back of this manual
to help identify parts during the assembly process.
B. To assist with the cab installation, leave all bolts
loose for later adjustment unless otherwise specified.
C. Read and understand all instructions before beginning.
D. Plastic washers have been supplied to provide a
weather seal under the heads of all exterior bolts.
The plastic washer should be installed under each
bolt head directly against the outside cab surface.
Care should be taken not to over tighten the fast-
eners and damage the plastic washer. Also use
steel washers as required. See diagram.
E. Apply a silicone sealant to seal any minor
gaps that may occur due to vehicle variations.
F. Use caution to avoid damaging the factory installed
threaded inserts. Begin the bolt engagement by hand
to avoid or correct potential cross threading.
TOOLS REQUIRED
driver and passenger.
Curtis accessory weights are listed in product
add additional weight to the base vehicle. All
Curtis Cabs, blades and general accessories
ADDED
WEIGHT
brochures. Deduct the accessory's total weight
from the vehicle's rated capacity and never
exceed the vehicle's rated capacity including
Exposure to Carbon Monoxide can Cause
illness, serious injury or death. Never
operate vehicle if suspicious of Carbon Monoxide. Inspect
exhaust system for leaks monthly. Leaks can result from loose
connections, corrosion, cracks or other damage to the exhaust
manifold. If leaks are found, repair or replace exhaust system.
Do not use vehicle until repair or replacement is complete.
p. 2 of 12
Fastener
Cab Surface
Steel Washer
Plastic Washer
Set of standard and metric sockets
Set of standard and metric open end wrenches
Drill
3/8" drill bit
Measuring Tape
Clamp
One Phillips Head Screwdriver
Scissors
One 3/8” Drive Ratchet
One 5/32” Allen Wrench (preferably “T” handle type)
One 3/16” Allen Wrench (preferably “T” handle type)

p. 3 of 12
1. VEHICLE PREP
1.1 Per fig. 1.1, remove the following five (5) items
from the tractor: the optional tool box and clamps from
the roll bar (if equipped), both grab handles, and both
turn signal lights from the fenders (identify the wires for
easier re-connection later). Save the turn signal lights,
washers, and nuts for re-use in step 13.
2. ROLL BAR BRACKETS
2.1 Per fig. 2.1, loosely install the roll bar brackets and
the roll bar mounts to the R.O.P.S. tubing (two places per
upright) (approximately where shown in relationship to
the removable pin for the fold-down R.O.P.S.. Ref.: the
center of the bolt hole should be approximately 14-1/2”
up from the fender and 36-1/2” up from the fender. When
left loose, these units will be able to slide up or down to
match the exact mounting holes in the back of the side
frames. Orient as shown for the right side and opposite
for the left side. Use the following hardware per setup:
one 5/16” x 1” long carriage bolt and one locknut. The
locknut is to be towards the outside of the tractor.
Fig. 1.1 (remove these items from tractor)
14-1/2” up from fender
Fig. 2.1 (roll bar bracket on right side of vehicle)
locknut here
(outboard)

p. 4 of 12
3. HARD REAR PANEL
Note: this is a separately purchased option on soft sided cabs.
It’s a standard included item on hard sided cabs. If installing
on a SS cab, remove snaps from rear edge of roof.
3.1 If not installing a hard rear panel, skip to step 4 below.
3.2 See fig. 3.2. With assistance, place the hard rear panel
on the tractor in front of the R.O.P.S. tubing oriented as
shown with the window towards the rear. The bulb rubber on
the bottom of the left and right sides should be pointing for-
ward. NOTE: per the inset picture in the top left hand corner
of fig. 3.2, be sure both removable pins for the fold-down
R.O.P.S. are oriented for easy outboard pin removal once the
optional hard rear panel is bolted in place.
4. COWL
4.1 Per fig. 4.1, position the cowl over the hood of the
tractor oriented so the top channel bend is towards the rear of
the tractor (fig. 5.1.1 also shows the orientation). The bulb
rubber seal around the hood area should be positioned to
point towards the seat. As shown in fig. 5.1, the lower bent
flange on the cowl sits on top of the rubber floor mat (not
under it).
5. SIDE FRAME
For ease of installation, remove the doors from side frames
by opening and lifting up off of pin hinges with the aid of an
assistant.
5.1 Per fig. 5.1, install the left side frame so the floorboard
sits on top of the rubber floor mat and on top of the bent
flange on the lower portion of the orange cowl as shown. Per
fig. 5.1.1, the mounting tab that is welded on to the side
frame fits into the bent channel on the cowl as shown. The
bulb rubber that seals against the rear fender should be point-
ing outboard to minimize covering the factory installed de-
cals.
Fig. 3.2 (view from front left side of tractor)
Fig. 4.1 (view from front left side of tractor)
Fig. 5.1 (view from rear left side of tractor)
bulb rubber
to point
towards the
seat
bent flange
on cowl
Fig. 5.1.1 (view from front left side of tractor)
mounting
tab is in here
hard rear
panel
bulb rubber
to point for-
ward

p. 5 of 12
5. SIDE FRAME (cont’d.)
5.2 Per fig. 5.2, use the following hardware installed
horizontally into the front of the side frame tubing (into
factory installed threaded inserts): three 5/16 x 3/4” long
button head bolts, three nylon washers, and three steel
washers. See helpful hint “D” on page 2 for proper place-
ment of nylon/plastic washers. Use caution to avoid
damaging the factory installed threaded inserts. Begin the
bolt engagement by hand to avoid or correct potential
cross-threading. Do not tighten bolts.
5.3 Per fig. 5.3, clamp the top corner of the cowl to the
side frame to assist in lining up the holes for the vertical
bolt. Use the following hardware in this location: one
5/16 x 3/4” long button head bolt, one steel washer, and
one locknut. The head of the bolt is to be up top as
shown. Tighten bolt and remove clamp.
5.4 Per fig. 5.4, attach the back side of the side frame to
the roll bar bracket assembly. Note: fig. 5.4 shows an
optional hard rear panel in place. Use the following hard-
ware in each of the four roll bar bracket assemblies: one
5/16 x 1” long button head bolt, one nylon washer, and
one steel washer. Thread into the factory installed thread-
ed inserts in the rear of the side frame tubing. Do not
tighten bolts.
5.5 For the remaining two threaded inserts per side
(one up top and one down bottom) on the back of the side
frame, leave them open if not installing a hard rear panel.
If installing a hard rear panel, use the following hardware
per side: two 5/16 x 3/4” long button head bolts, two ny-
lon washers, and two steel washers. Thread into the fac-
tory installed threaded inserts in the rear of the side frame
tubing. Do not tighten bolts.
5.6 Repeat all of section 5 for the opposite side frame.
5.7 Per fig. 5.7, new decals can be obtained from
Kubota and repositioned on the tractor if required.
Fig. 5.3 (view from front right side of tractor)
clamp here
head of vertical bolt
Fig. 5.4 (view from rear right side of tractor)
hard rear
panel
Fig. 5.7 (view from center of tractor)
Fig. 5.2 (view from front left side of tractor)
install
bolts
here
nylon washer, steel
washer, head of bolt

p. 6 of 12
6. WINDSHIELD SUPPORT
6.1 See fig. 6.1. With assistance, install the windshield
support to the top front corner of the side frames oriented
as shown with the bent flanges on the bottom. In the low-
er holes only, use the following hardware per side frame:
one 5/16 x 1” long button head bolt, one steel washer,
one nylon washer, and one locknut. Refer to the helpful
hints section on page two for the proper placement of the
nylon washer. Do not tighten bolts. Note: the upper hole
on each side will get hardware once the roof is installed.
7. WINDSHIELD
7.1 See fig. 7.1. Have the following items ready: four
5/16 x 1-3/4” long flat head bolts, four locknuts, and two
plastic spacer blocks. With assistance, install the wind-
shield hinges to the windshield support with the two
spacer blocks between the hinge and the windshield sup-
port. Attach windshield latches to windshield latch re-
ceivers on the cowl by squeezing tabs to retract spring
loaded pins. See fig. 7.1.1. Lift up on bottom of wind-
shield and close latches. Check alignment of windshield
with side frames and tighten hinge hardware. CAU-
TION: hinges are plastic components. Do not over-
tighten hardware. Torque to 7 foot-pounds maxi-
mum. Also tighten both lower windshield support bolts
(from step 6 above).
Fig. 6.1 (view from front left side of tractor)
install
bolt
here
leave empty for now
Fig. 7.1 (view from front right side of tractor)
3/4” thick spacer block
Fig. 7.1.1 (view from center of tractor)
latch
receiver

p. 7 of 12
middle
side bolt
Fig. 8.3 (view from front left side of tractor)
rear corner bolt
ref.: reflectors are back here
Fig. 9.2.1 (view from left side of tractor)
heads of
bolts up top
8. ROOF
8.1 Use a Phillips head screwdriver to punch a hole
through the headliner at any of the covered bolt hole lo-
cations (8 places). Punch holes from the inside out to
avoid having the headliner pull away from its glued sur-
face.
8.2 Install the roof oriented so the reflectors are to-
wards the rear of the vehicle. Use the following hardware
in the two front corners: one 5/16 x 1” long button head
bolt, one steel washer, one nylon washer, and one lock-
nut (locknuts on the inside surface). Install the bolt
through the roof, windshield support, and mounting tab.
See the helpful hints section on page two for placement
of nylon washers.
8.3 See fig. 8.3. The middle side and rear corner bolt
location on both the left and right sides uses the follow-
ing hardware per side: two 5/16 x 3/4” long button head
bolts, two steel washers, and two nylon washers. These
bolts are installed into factory installed threaded inserts
in the top of each side frame. NOTE: use caution to
avoid damaging the internal threads on the factory in-
stalled threaded inserts.
8.4 The remaining two holes in the middle front use the
following hardware: two 5/16 x 3/4” long button head
bolts, two steel washers, two nylon washers, and two
locknuts. Locknuts to be on the inside surface.
9. TIGHTEN ALL BOLTS
9.1 Tighten all bolts at this time including the carriage
bolts on the roll bar brackets, etc.. Note: the roll bar
brackets should end up parallel and/or perpendicular to
the R.O.P.S. tubing.
9.2 Per figures 9.2 and 9.2.1, use the two holes in the
side frame floorboard as a guide to drill 3/8” diameter
holes through the floor of the tractor. WARNING:
check underneath for obstructions before drilling.
With assistance, depress the inner-most brake pedal to
gain clearance for the drill to be vertical when drilling
the front right bolt hole. Install the following hardware
per side: two 5/16 x 1” long button head bolts, two steel
washers, and two locknuts. Locknuts to be underneath
the tractor. Tighten these bolts.
Fig. 9.2 (view from seat of tractor)
drill a
3/8” hole

p. 8 of 12
10. REAR CURTAIN
If installing a hard rear panel, skip this step and continue
with step 11 below.
10.1 Assemble the six (6) snaps on the rear curtain to
the six (6) snaps on the back side of the roof.
10.2 Dry fit the sides of the rear curtain to the wide in-
ner surface of the side frame rear vertical tubing as
shown in fig. 10.2. Install the supplied 1” wide hook vel-
cro to a clean, dry surface at room temperature for best
adhesion. Attach the curtain to the newly installed velcro.
11. UNDER SEAT FILLER
11.1 Per fig. 11.1, tip/raise the seat forward and position
the under seat vinyl filler as shown with the seat belt
bracket passing through the slit openings on each side.
Dry fit this and estimate where to apply the supplied 1”
wide hook velcro to the fenders, etc.. Reminder: for best
adhesion, apply self-adhesive backed velcro to clean, dry
surfaces at room temperature. The top middle section of
the under seat filler attaches to the bottom of the soft rear
curtain or to the bottom inside surface of a hard rear pan-
el as shown in fig. 11.1.1. For the hard rear panel, install
more of the supplied 1” wide velcro to suit.
Fig. 10.2 (view from center of tractor)
2” wide inner surface
of side frame rear
vertical tube
Fig. 11.1 (view from left side of tractor)
seat belt
bracket
opening
Fig. 11.1.1 (view from left side of tractor)
hard rear panel
is shown here

p. 9 of 12
12. DOORS
12.1 Apply grease to the pin hinges. With assistance, re
-install the doors onto the pin hinges. Work the doors
back and forth until the hinges are completely seated. If
necessary, specific adjustments can be made per the steps
below. Note: the top of the door should end up visually
parallel with the side of the roof. Note: the door latch is a
rotary type with two positions to close. Adjust door so
that when fully closed door latch clicks twice for total
engagement.
Per fig. 12.2, the large striker bolt and nut can be loos-
ened and reset higher or lower, in or out for better en-
gagement and door seal. Use two 19mm open end
wrenches. Note: finger guard to end up being centered
and facing inward.
Per fig. 12.3, the 1/4” hex head bolts on the door hinges
can be loosened on the rear tube, or on the door itself, or
in both places, in order to rotate or move the door up or
down and forward or backward as necessary for proper
alignment with side frame. Note: An assistant will be
needed for this step. Keep the hinge sleeves fully seated
on the pin hinges. Tighten all hinge bolts using caution to
not over tighten. Over tightening will crush (damage) the
structural tubing. Torque to 40 inch-pounds.
Per fig. 12.4, the inside latch can be moved forward or
back for proper engagement with the striker bolt. Loosen
the two hex head bolts shown to move the latch. Re-
tighten bolts.
CAUTION: FOR SAFE OPERATION, DO NOT
DRIVE WITH DOORS OPEN. MAKE SURE
DOORS ARE CLOSED AND PROPERLY
LATCHED WHEN DRIVING.
For soft sided doors, install the supplied vinyl coated
cable door stops between the upper bracket on the doors
and the upper bracket on the side frames. Use the follow-
ing hardware: four 5/16 x 3/4” long hex head bolts, eight
steel washers, and four locknuts. Do not tighten down
firmly. Allow for free pivoting.
For hard sided doors, install the supplied gas shocks to
the factory installed ball studs on the side frames and
doors with the small piston end towards the door.
Fig. 12.2 (view of striker bolt assembly)
Fig. 12.3 (exterior view of right side door)
Fig. 12.4 (interior view of right side door latch)
RIGHT

p. 10 of 12
13. TURN SIGNAL LIGHTS
13.1 Per fig. 13.1, re-install the turn signal light to the
welded bracket on the back side of the side frames. Use
the supplied wires to connect to the existing wiring un-
derneath the fender (see fig. 13.1.1). Repeat for opposite
side.
14. WINDSHIELD WIPER
14.1 Install the wiper motor per the installation instruc-
tions included with the wiper kit.
15. FINISHING TOUCHES
15.1 Peel protective film from the windows.
15.2 Install the supplied nut covers on the interior lock-
nuts (qty.: 20).
16. CARE AND MAINTENANCE
16.1 Once the doors are properly adjusted, lubrication
(preferably grease) can be applied to the striker bolts and
door latch assemblies. Re-apply periodically as needed
(same goes for the door pin hinges as necessary).
16.2 Check and tighten hardware after 40 hours of op-
eration. Periodically inspect and tighten hardware for the
remainder of the unit’s life.
16.3 Wash the painted surfaces of the unit with com-
mercial automotive cleaning products.
16.4 Clean windows with glass cleaner.
16.5 Vinyl components should be washed with a mild
solution of warm soapy water.
16.6 Clear vinyl can be easily scratched. Be careful
cleaning frost or snow from rear curtain. Do not roll cur-
tain in cold weather. The curtain becomes stiff and may
crack. Keep curtain clean.
Fig. 13.1 (view from rear left side of tractor)
both washers and nut on this side
Fig. 13.1.1 (view from rear right side of tractor)
connect wires