01-04-2022

Yes you can buy an American made four stroke and have the support of a major American engine producer.
This way you're assured the highest quality parts and technical support because you deal with the people that make'em.

Unique Rotary Valve Four Cycle Design - More economical and as QUIET as an electric.
Winner of fuel economy contests -- Up to 45 minutes on 6 oz of fuel.

HP  VT.21 Four Stroke #99-2301 with Roller Bearing Valve Support
HP  VT.21 Four Stroke #99-2302 Standard Head
VT.21 SPECIFICATIONS
Displacement
.21 cu.in. (3.5ccm)
Bore x Stroke
0.654 x 0.63
Power
.35 hp
RPM Range
2500 ~ 15,000
Weight
9.5 oz
Prop Size
8x5; 8x6; 9x5; 10x4
Prop Nut Thread
1/4" x28
VT.21 SPECIFICATIONS
Piston/Cyl Type
Dykes Ringed ABC
Crankshaft
Hardened supported by two ball bearings
Valve Type
Hard Chrome Rotary in bronze sleeve
Valve Train Drive
Bevel and spur gear via shaft
Carburetor Type
Twin Needle
Glow Plug
K&B 1L 7311 Std Long
See note a bottom of page about glow plugs in VT engines
ULTRA QUIET!
HP's unique design of four strokes are the quietest made. In fact, the VT.21 rivals an electric. Both engines are equipped with suburb mufflers that easily meet all DB requirements.
EXACTING TOLERANCES!
HP engines have always been renowned for their unsurpassed quality and precision. This tradition continues as all HP four cycles are produced with the latest computer controlled machines in our Southern California facility.
SUPER SMOOTH
HP has always been known as the smooth runners. The one piece hardened steel crankshaft with a massive counter weight is supported by 2 ball bearings. A light alloy forged conrod and cast piston are balanced perfectly. You'll be surprised just how smooth a engine can be.
OVERHEAD BBC rotary valve technology
Bronze, Brass, Chrome. HP pioneered rotary valves in model engines and utilize a true hard chrome valve running in a bronze sleeve. This arrangement never requires adjustment. No valve float and or power robbing valve spring tension to overcome.
Optional roller bearing supported valve Rather than the standard bushing, you can purchase the bearing head version to take the upward force of the valve during combustion. Both engines provide the same power, however the bearing head is less critical on the oil scavenging from the exhaust. Precision Crankshaft
Produced from solid bar stock with large counterbalance and then fully heat treated, these crankshafts are then precision ground to a tolerance of .0001 of an inch. This is why HP engines are known as the smoothest runners.

ABC ringed piston & cylinder assembly
A high silicon piston fitted with ring runs in a hard chrome plated brass sleeve precision ground to .0001 of an inch on both the inside and outside diameters.

Forged & bushed connecting rods
Each VT connecting rod is forged from high strength aircraft grade aluminum alloy then precision machined and fitted with bronze bushings at both ends
High pressure castings
All HP engines are pressure die cast from aluminum alloys. These castings are made by forcing molten aluminum into high strength tool steel dies at pressures as high as 3000 psi.
Ball Bearings
All VT's are equipped with double ball bearings on the crankshaft. The front is sealed on both sides eliminating blow by and rusting that is common in four cycle engines.
Click image for
larger image
with dimensions
IMPORTANT NOTE: The K&B 7311 glow plug works perfect in HP VT four stroke engines. Don't use R/C, 4 cycle, miracle, wonder or any other plugs that have anything extending from the end. These plugs can hit and destroy the rotary valve. Early VT.21's use a standard short plug like the K&B 1S 7321. You can identify the early version by the rotating valve, early used a bronze valve in a chromed sleeve, all later engines used a chrome valve in a bronze sleeve.

Click here for Owners Guide

Part Number

Description

Engine size

10-2301

Crankcase with valve and tower gear VT.21

10-2302

Crankcase with valve and tower gear FC.25

13-2301

Piston VT.21

13-2302

Piston FC.25

14-2301

Ring, Dykes type VT.21

14-2302

Ring, Dykes type FC.25

15-2301

Wrist pin, w/pads VT.21

15-2302

Wrist pin, w/pads FC.25

16-2301

Connecting Rod HP VT.21, FC.25

17-2301

Crankshaft HP VT.21, FC.25

18-0018

Front Bearing HP VT.21, FC.25

18-0019

Rear Bearing HP VT.21, FC.25

18-0020

Front Bearing HP VT.21, FC.25

18-0022

Roller Bearing HP VT.21, FC.25

19-2001

Collect for Prop Driver HP VT.21, FC.25

20-2002

Prop Driver HP VT.21, FC.25

23-2001

Prop Washer HP VT.21, FC.25

24-1101

Prop Nut HP VT.21, FC.25

24-2331

Muffler Nut HP VT.21, FC.25

25-2301

Screw Set HP VT.21, FC.25

26-2301

Teflon pads for wrist pin HP VT.21, FC.25

28-2301

Draw Bar to retain Carb (2 Req.) HP VT.21, FC.25

29-2301

Gasket for valve cover HP VT.21, FC.25

30-2301

Muffler with nut VT.21

30-2302

Muffler with nut FC.25

40-2301

Bearing head update kit VT.21

40-2302

Bearing head update kit VTFC.25

40-2311

Bearing head update kit VTFC.25 AUTO

41-2301

Standard Head cover VT.21

41-2302

Roller Head cover VT.21

41-2303

Standard Head cover VTFC.25

41-2304

Roller Head cover VTFC.25

41-2305

Auto heat sink cover Standard Head VT25

41-2306

Auto heat sink cover Roller Head VT25

43-2301

Pinion gear pin HP VT.21, FC.25

44-2301

Lower rear large bevel pinion gear HP VT.21, FC.25

46-2301

Pinion gear retaining strap HP VT.21, FC.25

46-2302

Valve shim set HP VT.21, FC.25

46-2303

Con rod shim HP VT.21, FC.25

80-2301

Carburetor HP VT.21

80-2302

Carburetor HP VT FC.25

80-2311

Carburetor HP VT FC.25 AUTO

81-2301

Carb body HP VT.21, FC.25

81-2311

Carb body HP FC.25 auto

82-2301

Carb barrels HP VT.21

82-2302

Carb barrels HP VT FC.25

83-2101

Throttle arm HP VT.21, FC.25

83-2301

Barrel Spring HP VT.21, FC.25

84-2102

Throttle arm nut HP VT.21, FC.25

84-2301

Barrel cam screw/nut HP VT.21, FC.25

84-2302

Spray bar HP VT.21, FC.25

85-2101

High Speed Needle HP VT.21, FC.25

85-2302

Low Speed Needle HP VT.21, FC.25

85-2312

Low Speed Needle for car engine HP FC.25 auto

86-2301

Auto carb insulator HP FC.25 auto

87-2301

Needle, housing & nipple HP VT.21, FC.25

88-2301

Carb Manifold HP VT.21, FC.25
- VT "T" pressure fitting -
- VT Crankcase pressure nipple -
- VT Crankcase Plug -

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