Rotax 125 MAX Adjustable Variable Exhaust
Introduction: This information is in addition to the valid repair manual. Safety requirement has to be taken from the valid repair manual. This information is only for internal usage.. BRP-Powertrain 2010.04.09
Installation 1. Clean the cylinder with brake cleaner and check impulse bore for cleanliness. (visual) Presentation Rotax exhaust valve only for internal use 3
Installation 2. Clean the Exhaust valve with brake cleaner and scotch brite and check the total length of the exhaust valve. ( 72 +/- 0,3) ATTENTION: Stud screw has to be locked with LOCTITE 648 Presentation Rotax exhaust valve only for internal use 4
Installation 3. Insert the exhaust valve as shown on the picture and assure free movement of the exhaust valve. Presentation Rotax exhaust valve only for internal use 5
Installation 4. correct metallic contact between valve and cylinder not correct gasket interferes contact between valve and cylinder Apply the gasket on the cylinder and assure metallic contact between exhaust valve and cylinder. Presentation Rotax exhaust valve only for internal use 6
Installation 5. Apply the valve rod housing to the cylinder and check the exhaust valve for free movement. In case the exhaust valve piston get caught, check the position of the valve rod housing. Presentation Rotax exhaust valve only for internal use 7
Installation 6. Apply the o-ring to the stud screw. Presentation Rotax exhaust valve only for internal use 8
Installation 7. Apply the bellow on the valve housing and check the sealing surface for proper sealing. The small hose spring at the bottom of the bellow has to be installed correctly to the groove of the bellow. Presentation Rotax exhaust valve only for internal use 9
Installation 8. 10 NM Hand tighten the exhaust valve piston to the stud screw and adjust a total length of 73,5 +/- 0,3 mm Torque the exhaust valve with 10 Nm to the cylinder. Presentation Rotax exhaust valve only for internal use 10
Installation 9. Apply the hose spring with Rotax special tool 276070 to the bellow. Assure free movement of the exhaust valve and make a visual check for the correct installation of the hose spring to the groove. Presentation Rotax exhaust valve only for internal use 11
Installation 10. Apply the compression spring to the Exhaust Valve and mount the Valve Cover by means of the spring clip to the housing. Presentation Rotax exhaust valve only for internal use 12
Troubleshooting R.A.V.E (ROTAX ADJUSTABLE VARIABLE EXHAUST) Presentation Rotax exhaust valve only for internal use 13
Engine concept Rotax engine 125 MAX Rotax 125 MAX versus typical 100cc kart engines 22 125 Max 100cc 20 engine performance [kw] 18 16 14 12 10 8 6 4 2 2% oil 0 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 15000 16000 17000 18000 19000 20000 5-8% oil engine speed [rpm] Presentation Rotax exhaust valve only for internal use 14
Engine concept Rotax engine 125 MAX Performance characteristic of Rotax engine 125 MAX 22 performance of engine [kw] 20 18 16 14 12 10 8 6 4 2 Exhaust valve closed till 7.500 rpm Tuned exhaust pipe in combination with ignition timing 7.500 rpm 12.500 rpm Ignition timing 12.500 14.000 rpm 0 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 engine speed [rpm] Presentation Rotax exhaust valve only for internal use 15
1) Exhaust valve exhaust valve closed exhaust valve opened Low exhaust port timing = longer use of combustion energy High exhaust port timing = shorter use of combustion energy Till 7.500 rpm: Exhaust valve closes by compression spring (adjustable) At 7.500 rpm: Exhaust valve opens through raising pressure in the exhaust system Presentation Rotax exhaust valve only for internal use 16
1) Exhaust valve Pressure in the exhaust system (schematic diagram) exhaust valve closed exhaust valve open pressure 1 2 3 4 5 6 7 8 9 10 11 12 engine speed (rpm) The raising pressure in the exhaust system causing the exhaust valve to open. Presentation Rotax exhaust valve only for internal use 17
1) Exhaust valve Correct opening timing of the exhaust valve Motorleistung [kw], performance of engine [kw] 22 Leistungskurven mit geschlossenem und offenem Auslaßschieber performance graphs with closed and open exhaust valve 20 18 16 Opening timing too early Optimal opening timing 7.500 rpm Opening timing too late Leistungskurve 2, performance graph 2 14 12 10 8 Leistungskurve 1, performance graph 1 6 4 2 0 3.000 4.000 5.000 6.000 7.000 8.000 9.000 10.000 11.000 12.000 13.000 14.000 15.000 Motordrehzahl [1/min.], speed [rpm] Presentation Rotax exhaust valve only for internal use 18
1) Exhaust valve Standard setting of the exhaust valve 5 mm = approx. 2 inch Adjustment of the exhaust valve Ë at the race track Ë engine must have operation temperature Ë accelerate from 5.000 rpm at full throttle as soon as exhaust valve opens, noise is changing significantly. Ë exhaust valve has to be adjusted to open at 7.500 rpm Adjustable rpm range for exhaust valve opening Approximately +/- 300 rpm Presentation Rotax exhaust valve only for internal use 19
1) Exhaust valve Re-adjustment of the exhaust valve is just necessary if the Ë cylinder or the height of the cylinder (base gasket) has been changed Ë condition of the isolating mat in exhaust muffler has changed (worn). Presentation Rotax exhaust valve only for internal use 20
1) Exhaust valve Troubleshooting Problem: Missing performance till 7.500 rpm ( bottom end performance ) Exhaust valve does not close completely wrong Short use of combustion energy = high exhaust port timing Possible reason: Exhaust valve does not completely close. Solution: Check assembly of exhaust valve. Exhaust valve has to touch the cylinder surface in closed position. Metallic noise at closing has to be noticeable. Exhaust valve completely closed correct Long use of combustion energy = low exhaust port timing Presentation Rotax exhaust valve only for internal use 21
1) Exhaust valve - Troubleshooting Problem: Delayed throttle response out of the curve. Track sector: Å To the curve: Engine revs 12.500 rpm, exhaust valve is open. Ç Middle of the curve: Engine revs drop to 9.000 rpm, carburettor slide is closed, exhaust pressure drops exhaust valve closes. 2 3 É Out of the curve: Engine revs 9.000 rpm, carburettor slide open delayed response of the engine 1 Presentation Rotax exhaust valve only for internal use 22
Ski-Doo Lynx Sea-Doo Evinrude Johnson Rotax Can-Am Presentation Rotax exhaust valve only for internal use 23 2006 Bombardier Recreational Products Inc. All rights reserved. Trademark of Bombardier Recreational Products Inc. or its affiliates.