The #4 main bearing assembly is engineered to absorb the tremendous forces imposed by the propeller. Cast of special bearing alloy, the large #4 main bearing allows for oil control capability for the propller. Click here for a detailed technical study of the #4 main bearing.

#4 main bearing assembly    $280.00

To order:
Please call 760-244-3074, or CLICK HERE to download our printable order form (Adobe PDF).


Revmaster has been manufacturing the RevFlow series injector carburetor since 1981. The major components of the RevFlow are precision die cast, not machined from bar stock. The die casting process allows for many intricate features to be cast in, thus reducing manufacturing costs. The injector unit incorporates a once-patented variable jet for fuel metering and a guillotine slide which controls the air flow. The two parts work in unison, thus providing the engine with the proper fuel/air mixture.

The fuel metering needle is ground with a flat tapered side which gives it an asymmetrical shape. The needle is attached to the slide and is allowed to float so it is self-aligning when inserted into the fuel nozzle. The head of the needle is configured so it cannot rotate while in service and is spring-loaded so the fuel mixture can be fine-tuned during the initial installation via a slotted adjusting screw. Several throat sizes and needle configurations are available.

The guillotine slide is actuated by a wheel and leaf spring that opens and closes to the throat opening when the wheel is rotated via the control arm. The slide has four flutes that guide it very precisely on several surfaces so the transition from idle to full power is without hesitation.

When the slide is in wide-open position, there are no other obstructions in the way of the air flow except for the needle, thus allowing for much greater air flow than with throttle bodies which have typical butterfly valves. The flat side of the needle is oriented towards the engine and produces a low-pressure on the back side which in turn causes fuel to flow in relation to the air flow.

This characteristic has altitude compensation benefits due to the variance in air density at higher altitudes. In order to manually control the mixture, the injector unit is equipped with a manual mixture control and idle cutoff. Besides controlling the mixture, this system will allow the fuel to be cut off at the nozzle, thus eliminating fuel leakage from the fuel line. Then, on restart, the fuel is at the nozzle for priming and starting.

The unit is equipped with two control arms; one for throttle and one for mixture cutoff. They require vernier type controls with at least 3.5″ travel with solid wire ends. Cable housings are connected to the injector body via cable housing attach points. This eliminates any movement in the cable housing which can cause erratic control problems. The wire ends of the controls are secured at the control arms with barrel clamps.

The fuel inlet fitting is a flared AN-4. The unit is mounted to the intake system by a hose and two clamps. The hose I.D. on most units is 1.5″. Flanged adapters can be provided on request.

In the event multiple units are required, such as for in-line engine applications, up to four units can be ganged on a single throttle shaft.

RevFlow injector sizes range from 28, 30, 32, 34, 36, 38, 40, 42, and 44mm. An alternate air source assembly is recommended for most single unit installations. This unit consists of an air filter, open on both ends, mounted onto the air horn of the injector and held on with a clamp. The ram air tube is clamped onto the opposite end.

The tube incorporates a valve that controls the ram air. When in the closed position the ram air is cut off and the engine is digesting warm filtered cowled air.

The RevFlow injector is a 1 to 2 psi low pressure injector. It will function well on gravity feed, although some applications require a fuel pump. When a fuel pump is installed, the fuel pressure should be maintained at a nominal 1.5 psi. This is best accomplished with a fuel return line to the source. The return line can be restricted to achieve the 1.5 psi.

For VW engine applications, Revmaster manufactures a special oil pump/fuel pump/oil filter assembly. This allows for an engine-driven fuel pump to be incorporated into certain requirements.

The RevFlow injector unit is floatless; therefore, it lends itself to many installation configurations; horizontal, vertical, etc. The RevFlow injectors have been installed in many various types of experimental aircraft over the years, with excellent service history. The unit is not type certificated and no such claims have been made, intentionally or otherwise.

Under certain moist atmospheric conditions with air temps ranging anywhere from 20 to 90 degrees F it is possible for ice to form in the induction system. The rapid cooling in an induction system using a float type carburetor is caused by the absorption of heat from the air during vaporization of fuel and, also due in part to the high air velocity, causing a low pressure area through the carburetor venturi. As a result of the latter two influences, the temperature in the mixing chamber may drop as much as 79 degrees F below the temp of incoming air. If this air contains a large amount of moisture, the cooling process can cause precipitation in the form of ice, generally in the vicinity of the butterfly which may build up to such an extent as to cause engine stoppage. In a float type carb, the fuel jet is ahead of, or just below, the venturi and throttle butterfly which means that the fuel is being impinged directly in the worst possible place for icing…the carb venturi. Since the RevFlow injector carburetor does not contain a venturi, nor a butterfly valve, the fuel and air is mixed further downstream, beyond the float type venturi refrigeration chamber. The absence of these parts accounts for the decreased likelihood for ice in this type of system.

If ice were to form, it would most likely collect in the intake manifold T area, however, tightly cowled engines with internal exhaust systems would retard or preent this from happening. The alternate air source/ram air cut off valve also assists in this matter. When the ram air is cut off, the engine will digest warm air through the alternate air filter. The exhaust system we usually have in the KR air frame is a four into one, whereas the #4 exhaust pipe runs parallel to the intake manifold. This exhaust heat keeps the intake system above freezing.

The higher the pressure drop in the intake tract, the more likely the system could ice. At higher power settings the pressure drop is lower and less prone to icing. At lower power settings, the pressure drop is much higher and more prone to icing. Auto fuel vaporizes more completely in the same time as 100LL. Thus, a lower air temp will result. This will create a lower threshold for icing. This should be considered when switching over to auto fuel.

CLICK HERE for a order form.



CLICK HERE for order form.

02-00-06 Crankshaft, forged 720.00
02-00-10 #3 main bearing, std. 20.00
02-00-14 Step woodruff key 4.25
02-00-17 Thrust spacer (3) shim 4.50
02-00-25 Gear, crank timing 38.00
02-00-26 Nut, gear retainer 21.00
02-00-27 Nut, set screw .20
02-00-28 Dowel, crank (2) 1.20
03-00-00 Con rod (4) 137mm 230.00
03-00-00-A Con rod (4) 139.7mm 230.00
03-00-00-B Con rod (4) 142.24mm 2″ jrnl w/9mm bolts 250.00
03-00-05 Set con rod bearings 19.00
04-00-00 Crankcase 1360.00
04-00-06 Main bearing alignment pin (6) .90
04-00-07 Case stud seals (6) 1.20
04-00-10 Main bearings #1 & #2 75.00
04-01-00 Cam bearing set 18.00
04-01-05 Cam followers (8) 75.00
04-01-12-B Camshaft 274 degrees (390 lift) w/gear 140.00
04-02-01 Rear crank seal 6.00
04-02-02 Camshaft plug 1.25
04-02-04 Crank flange key 1.75
04-02-05-AS #4 main bearing assembly 280.00
04-02-05 #4 main bearing only 250.00
04-02-06 1/8″ pipe plug .60
04-02-09 #4 main int. rotary seals (2) 10.40
04-02-10 #4 main outer seal 10.50
04-02-11 #4 main seal snap ring 2.25
17-02-04 Tube fitting, #4 main 2.15
04-05-00 Case stud washers (6) 1.80
04-05-01 Lock nuts, main case (6) 4.20
04-05-05 Secondary case washers (28) 5.60
04-05-06 Secondary lock nuts 8mm (20) 14.40
04-05-07 Top case bolt (long) .55
04-05-08 Top case bolt (short) .55
04-05-09 Bottom case bolts (2) 1.60
04-06-02 Plug seal 1.20
04-06-03 Threaded plug 5.00
05-00-00 Crankshaft flange removal tool 32.00
05-00-00-2 Crankshaft flange 305.00
05-00-01 Flange washer .75
05-00-02 Flange bolt LH (forged shaft) 58.00
05-00-05 Bolt plug .75
05-00-06 Flange moisture seal 2.25
06-00-01 Dipstick 8.00
06-00-04 Set piston rings 92mm 1.5mm 60.00
06-00-05 Set piston rings 82mm 2.mm Call
06-01-00-2 92mm cylinders/pistons set CIMA 335.00
06-01-00-4 94mm cylinders/pistons set CIMA 335.00
06-01-09 Cylinder stud kit (16) 64.00
07-00-05 Cyl heads, pair complete 94 bore, dual plug 995.00
07-00-06 Cyl heads, pair complete 75HP 92 bore, dual plug 995.00
07-00-07-B Spark plug covers (4) cast 42.00
07-01-05 Intake valves, 40mm SS (4) 48.00
07-01-06 Exhaust valves, 32mm SS (4) 48.00
07-01-07 Valve springs (8) 24.00
07-01-08 Spring ret. (8) 10.00
07-01-09 Split cotters (16) 8.80
Valve seats installed (8) $45.00 ea. 360.00
08-01-00 Push rod tubes (8) 20.00
08-01-01 Tube seals (16) 4.50
08-01-02 Cyl head washers (16) 4.50
08-01-03 Cyl head nuts (16) 6.65
08-02-00 Push rods, steel (8) 38.00
08-02-01 Push rods, alum (8) 45.00
08-03-00 Rocker arm assembly (2) 96.00
09-01-00 Sump gasket (2) 1.80
09-01-01 Oil strainer 4.75
09-01-11 Oil sump side drain assembly 85.00
09-01-14 Washers (6) 3.60
09-01-15 Cap nuts (6) 3.60
10-01-00 Copper mesh oil separator 1.45
10-01-01 Gasket, breather .25
10-01-02-A Breather plate 24.00
10-01-03 Breather ret. bolts (4) .85
10-01-05 Breather fitting .65
10-01-06 Breather hose 2.25
10-01-08 3/8″ plug, oil block-off (2) 2.00
10-01-10 Fuel pump gasket .50
10-01-11 Fuel pump cover plate 8.55
10-01-15 Oil fill cap 18.00
10-01-16 Oil fill cap O ring .35
10-01-20 L/L front block-off plate 10.00
10-01-22 L/L front gasket .35
11-00-00-AS Shipping legs (4) exhaust pipes 80.00
11-01-02-A Starter flywheel for magneto 265.00
11-01-02-B Starter flywheel for CDI 325.00
Flywheel bolt socket 9.50
Ring gear (only) 72.00
11-01-06 Alternator rotor 170.00
11-02-07 Rotor ret. screws (6) 3.60
11-01-08 Rotor lock washer (6) .90
1-01-09-A Mag cplg. (non-starter engine) 45.00
11-01-11-A Flywheel dowel pin (2) 2.00
1-01-13-B Flywheel ret. screws (4) 20.00
1-01-14-A Alternator stator (20 amp) 160.00
11-01-16 Stator ret. screws (4) 1.20
11-01-17 Stator lock washer (4) .48
11-01-30 Voltage regulator/rectifier 65.00
11-02-00 Mag mount housing (for Bendix) 185.00
11-02-04 Housing bolt, 55mm (2) 3.30
3.30 Housing bolt, 60mm (2) 3.30
11-02-06 Housing bolt washer (4) 1.00
11-02-08 Housing bolt lock nuts (2) 2.20
11-03-01 Starter bolts (2) 2.60
11-03-03 Starter bolt washers (2) .60
12-00-12 Mag drive rubber vib. (2) 12.00
12-00-13 Mag drive ret. cup 15.00
13-01-00 Spark plugs NGK3932 3.65
Spark plug socket machined to 1 12.50
14-00-00 Slick single ignition magneto Call
14-00-05 Mag hold down clamp (2) 10.20
14-00-15 Ground terminal assembly, P-lead kit (2) Call
14-01-00 Rocker arm covers, complete 60.00
14-01-01 Rocker arm cover gasket (2) 5.00
14-01-02 Rocker arm cover bolts (4) 2.00
14-01-03 Rocker arm cover washers (4) 2.40
15-00-00 Lower intake manifold 65.00
15-00-01 Intake manifold, left 125.00
15-00-02 Intake manifold, right 125.00
15-00-03 Intake manifold gaskets (2) 3.00
15-00-06 Intake manifold coupling hose (3) 30.00
15-00-07 Coupling hose clamp 5.00
15-00-10 Set intake manifold 345.00
15-02-05 Injector coupling hose 10.00
15-02-10 RevFlow flange adapter Call
15-02-11 Air filter 45.00
15-02-15 Alternate air source/ram air filter assembly 130.00
15-04-02 RevFlow carburetor 30 – 36mm 385.00
RevFlow carburetor 38 – 40mm 405.00
16-00-00 Oil pump, single function internal outlet 38mm gears 95.00
16-00-00-T Oil pump, dual body for turbo 265.00
16-00-01 Oil pump with oil filter mount, oil bypass 38mm gears 365.00
16-00-05-B Pump cover, oil bypass with filter mount, without pump 185.00
16-01-00-AS Oil cooler assembly with bracket, lines 285.00
16-01-05 Oil line, case to cooler 65.00
16-01-06 Oil line, filter to cooler 65.00
16-01-11 AN8 fitting eng case 18 X 1.50m 13.50
16-01-12 Oil cooler, bare 135.00
16-01-15 Fuel pump/oil pump assembly (outright) 38mm gears 390.00
16-06-06-D Geared starter for 109T ring gear 225.00
16-06-06-E Hi-torque starter for 12v ring gear 295.00
19-00-00 Vacuum pump bracket, pulley, bolt 175.00
20-00-15 Engine mount sleeves (4) 8.00
20-00-16 Engine mount conical bushings set (8) 38.00
20-00-17 Wide area washers (4) 4.00
20-00-20 Engine mount hardware kit, complete 75.00
20-00-30 Sonex engine mount hardware kit (special) 100.00
26-00-51 Prop crush plate 40.00
26-00-54 Prop extension 3 365.00
Prop extension 4 375.00
Q-2 or KR exhaust system, mild steel 350.00
Q-2 or KR exhaust system, stainless steel 510.00