HPI F
FEATURES: Composite construction slide valve,
7.5mm 3 needle carburetor,
high speed needle, idle screw and low speed needle are set flush with the carburetor body for factory settings
8 port chrome plated brass sleeve ABC cylinder construction, "A"luminum piston with a "B"rass cylinder that is "C"hrome plated Purple anodized billet aluminum heat sink head Round rear exhaust port Cast aluminum crankcase with heatsink fins
Machined pilot shaft crankshaft with collet preinstalled
Knife-edge billet aluminum connecting rod with dual bushings.
High flow 2-stage air filter dramatically reduces intake restriction as it smoothes and straightens air flow Two year limited warranty
INCLUDES: Nitro Star .28 F4.6 glow engine Glow Plug - HPI R5 cold plug (
HPIG1504 for a replacement) Dual Stage Air Filter (
HPIC7198 for replacement) Instructions and exploded views
SPECS: Height/bottom of Mounting Flanges/top of Cylinder Head: 4" (101mm)
Height/bottom of Crankcase/top of Cylinder Head: 4.5" (114mm)
Length from Pull Starter to Front Bearing: 3.3" (84.5mm)
Length from Pull Starter to end of Crankshaft: 4.6" (117mm)
Width at Mounting Flanges: 1.81" (45.9mm)
Mounting Hole Center Same Side: .82" (21mm)
Mounting Hole Center Opposite Side: 1.42" (36mm)
Bore: 18.68mm
Stroke: 16.6mm
Crankshaft diameter: 5mm (clutch bell area)
Crankshaft diameter: 6.7mm (threaded portion) Displacement: 4.6cc (.28 ci)
HPI K
FEATURES: Composite construction slide valve, 3 needle carb with hand
adjustable high speed needle (the stock carb settings are made flush
for convenient "back to factory settings")
8 port chrome plated brass sleeve
True ABC cylinder construction
Purple anodized machined aluminum heat sink head
Rear exhaust round port
Cast aluminum crankcase features heatsink fins
Machined pilot shaft crankshaft with collet preinstalled
Knife-edge billet aluminum connecting rod with dual bushings.
Dual stage air filter dramatically reduces intake restriction as it
smoothes and straightens air flow
INCLUDES: Nitro Star .28 (4.6) glow engine
Glow Plug - HPI R5 cold plug ( for a replacement)
Dual Stage Air Filter ( for replacement)
Instructions and parts break down
SPECS: Crankcase: 3.29 inch (83.5mm) (from rear of case to front without shaft)
Height: 4.40 inch (111mm) (from bottom of case to the top of the head)
Width: 1.81 inch (mount flange)
Mount Holes: 1.42 inch (measured from center to center width)
Mount holes: .82 inch (Between holes front and back)
RPM: Max 39,000 RPM
Crankshaft diameter: 5mm (clutch bell area)
Crankshaft diameter: 6.7mm (threaded portion)
Crankshaft screw: 3 x 12mm caphead screw
Capacity: 4.60cc (.28 ci)
I have worked on the inside of both engines several times and would say in my humble opinion the F is a faster engine.
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