Filed Under (KTM) by admin on 12-11-2010
Repair manual KTM 250 / 300 / 380 Art No 3206004 -E 2-2C main jet jet needle jet needle air control screw idle adjusting screw idle jet throttle valve Idling range A Operation with closed throttle valve. This range is influenced by the position of the air control screw 1 and the idle adjusting screw 2 . Only make adjustments when the engine is hot. To this end, slightly increase the idling speed of the engine by means of the idle adjusting screw. Turning it clockwise produces a higher idling speed and turning the screw counterclockwise produces a lower idling speed. Create a round and stable engine speed using the air control screw (basic position of the air control screw = open by 1.5 turns). Then adjust to the normal idling speed by means of the idle adjusting screw. Opening up B Engine behavior when the throttle opens. The idle jet and the shape of the throttle valve influences this range. If, despite good idling-speed and part-throttle setting, the engine sputters and smokes when the throttle is fully opened and develops its full power not smoothly but suddenly at high engine speeds, the mixture to the carburetor will be too rich, the fuel level too high or the float needle is leaking. Part-throttle range C Operation with partly open throttle valve. This range is only influenced by the jet needle (shape and position). The optimum part-throttle setting is controlled by the idling setting in the lower range and by the main jet in the upper range. If the engine runs on a four-stroke cycle or with reduced power when it is accelerated with the throttle partly open, the jet needle must be lowered by one notch. If then the engine pings, especially when accelerating under full power at maximum engine revs, the jet needle should be raised. If these faults should occur at the lower end of the part throttle range at a four-stroke running, make the idling range leaner; if the engine pings, adjust the idling range richer. Full throttle range D Operation with the throttle fully open (flat out). This range is influenced by the main jet and the jet needle. If the porcelain of the new spark plug is found to have a very bright or white coating or if the engine rings, after a short distance of riding flat out, a larger main jet is required. If the porcelain is dark brown or black with soot the main jet must be replaced by a smaller one. mixture too rich: too much fuel in proportion to air mixture too lean: not enough fuel in proportion to air 1 2 OPERATING RANGES OF THE CARBURETOR 2-3C Carburetor adjustment Basic information on the original carburetor setting The original carburetor setting was adapted for an altitude of approx. 500 meters (1600 ft.) above sea level, and the ambient temperature of approx. 20°C (68°F), mainly for off-road use and central European premium-grade fuel (ROZ 95 MOZ). Mixing ratio 2-stroke motor oil : super fuel 1:40 – 1:60. Basic information on a change of the carburetor setting Always start out from the original carburetor setting. Essential requirements are a clean air filter system, air-tight exhaust system and an intact carburetor. Experience has shown that adjusting the main jet, the idling jet and the jet needle is sufficient and that changes of other parts of the carburetor will not greatly affect engine performance. RULE OF THUMB:
Filed Under (Yamaha) by admin on 21-01-2012
1) The “blue” colored screw in the image is the duration adjustment screw. Underneath the head of the screw is a lock nut and the bracket arm that the screw is threaded into. To decrease the amount of fuel squirted the adjustment screw is turned “clockwise” or in. To increase the amount of fuel squirted the adjustment screw is turned “counter clockwise” or out. To get the max, amount of decrease remove the screw and take the lock nut off of the screw. Then replace the screw into the cam arm, then replace the lock nut underneath the arm on the screw. this gives you another 3/32″ of an inch in which the screw can be screwed in.
2) Turn the adjustment screw fully clockwise or IN. Start your engine, Blip your throttle open, if the engine stutters, (hesitates), it is not getting enough fuel so turn the screw counter clockwise to increase the amount of fuel squirted from the accelerator pump into the carburetor. Keep blipping the throttle and adjusting the screw till the carburetor starts to cough. Stop here and turn the screw back in till the coughing stops. Tighten down the lock nut. This should give you the best throttle response with the least amount of coughing and backfiring out the carburetor. Timing Adjustment Screw This is the “Green” colored screw just above the Blue duration adjustment screw. The” Mucker” said it best,,,,, This upper screw adjusts the “timing” of the squirt. By altering it’s setting, you can advance or delay the onset of the fuel squirt. But probably, it won’t have to be touched
Filed Under (Triumph) by admin on 29-10-2010
Jets: These are made in various sizes ranging from.099 inches to.1875 inches, the larger sizes being used only for racing or very high performance engines. The two sizes most commonly found on production cars are the.090 inch and the.100 inch. The size of the jet will be found stamped on the jet head. The figure “nine”wilt indicate that it is the.090 inch and the figure “one”will indicate the.100 inch jet. When tuninga production car the jets size should be checked to make sure that it is of the size recommended by the manufacturers. Centering of Jet: If for any reason, the jet assembly has been removed, it will be ne cessary to recenter the jet. First, remove the clevis pin at the base of the jet which attaches the jet head to the jet operating lever. Withdraw the jet completely and remove the adjusting nut and spring, then replace the adjusting nut, without its spring, and screw it up toits highest position. Slide the Set into position until the jet head is against the base of the adjusting nut. When this has been done, find out if the piston is perfectly free by lifting it up with the finger and allowing it to drop. If the piston is not entirely free, slacken the jet screw and manipulate the lower part of the assembly, including the projecting part of the bottom half of the jet bearing, adjusting nut, and jet head. Make sure that this assembly is now slightly loose. The piston should then rise and fall quite freely as the needle is now able to move the jet into the required central position. The jet screw should now be tightened and a further check made to determine that the piston is still quite free. When complete freedom of the piston is achieved the jet adjusting nut should be removed, together with the jet, and the spring replaced. Experience has shown that a large percentage of carburetors, which have given trouble has been due to the incorrect centering of jets. Jet Needles— These are made in a great variety of sizes, probably now well over two hundred and fifty, and each type of engine hasaneedlethat has been selected, after very careful tests have been carried out, to give the best all-round performance. Most manufacturers actually give three alternative needles for each type and size of engine, these needles clearly being listed by the manufacturer “Standard”, “Rich”or”Weak”and before tuning is started the needle, which is marked on the shank should be checked against the manufacturer’srecommendation to make quite sure that the right needle is fitted; this is most important.
Filed Under (Yamaha) by admin on 10-11-2010
1. Remove the vacuum slide from the carburetor. 2. Remove the OEM needle, spacer and washers, noting order of assembly. 3. Counting from the top to the bottom, install the new Baron needle clip on groove #4 for 04-07 models and on groove #5 for 99-03 models of the replacement. NOTE: Baron adjustable needle – The top is the blunt end of the needle. 4. Reinstall the OEM spacer and washers as shown in this diagram. 5. Reinstall the vacuum slide along with the diaphragm spring. 6. Reattach the diaphragm cover back and tighten screws. NOTE: Verify that the slide maintains its full range of movement. 7. Drain the fuel from the float bowl and remove the bowl cover. 8. Remove the OEM main jet and replace it with a Barons genuine Mikuni main jet. Install the correct main jet as indicated in JET SELECTION area above on this page. Our install guides provide a basic outline on the proper installation of our products. Further tuning and/or fitment may be required. Page: 2 BA-2420RD NEEDLE/JET KIT – Yamaha Road Star (99-07) 9. Thoroughly clean the inside of the float bowl prior to reinstalling it. 10. Reassemble the carburetor by reversing the order of step #1 through step #10. Use the new cap head allen screws in place of the OEM phillips head screws. 11. Locate the fuel mixture screw – it will either be a screw head or a brass plug. If it is a screw head, skip to step #11c. 11c. If you see a brass plug with a small hole in the center, proceed as follows: With the drill bit, carefully and slowly drill through the fuel mixture plug. CAUTION: The fuel mixture screw is located directly beneath this plug. Be prepared to stop the drill and remove the bit the instant you break through the plug. Insert the self-tapping sheet metal screw into the drilled hole and remove the plug. With air/fuel screw now accessible, use a flat blade screwdriver to turn the screw clockwise until it seats, then carefully turn it counter-clockwise 3 1/2 turns. Refer to step #16 for assistance in fine tuning the setting of the air/fuel adjustment screw. 12. Reinstall the carburetor. We strongly suggest that you attach the throttle cables prior to mounting to intake manifold. 13. Reconnect the fuel line, ensuring the clamp is firmly in place. 14. Reinstall all vent hoses and electrical connectors that were previously removed, checking for any obstructions or blockage. 15. Reinstall the OEM air filter assembly or, if you are installing our Big Air Kit (BAK), follow the instructions that accompany that kit, then continue with next step. NOTES: When the BAK is installed, the vent hose that terminated on the rear of the OEM airbox can be relocated in any safe position that does not kink or pinch it. It is important to verify proper throttle operation before starting the engine.
Filed Under (Yamaha) by admin on 16-01-2012
Remove the vacuum slide from the carburetor. • Remove the OEM needle and spacer, noting the order of assembly. • Counting from the top to the bottom, install the new Baron needle clip on groove #4 of the replacement Baron adjustable needle. • Reinstall the OEM spacer and washer. • Reinstall the vacuum slide along with the diaphragm spring. • Reattach the diaphragm cover and tighten its screws. Note: Verify that the slide maintains a full range of movement! • Drain the fuel from float bowl and remove the bowl cover. • Remove the new cap head Allen screws in place of the OEM Phillips head screws. • Repeat above steps for other OEM main jet and pilot jet, and replace them with Baron’s main and pilot jets. • Thoroughly clean the inside of the float bowl prior to reinstalling it. • Reassemble the carburetor by reversing the order of previous steps. Use thecarburetor. • Locate the fuel mixture plug on each carburetor; it will either be a screw head or a brass plug. If it is a screw head, skip to step c . If you see a brass plug with a small hole in the center, proceed as follows: a. With a 5/32″ drill bit, carefully and slowly drill through the fuel mixture plug for each carburetor. CAUTION: The fuel mixture screw is located directly beneath this plug. Be prepared to stop the drill and remove the bit the instant you break through the plug. b. Insert a self-tapping sheet metal screw into the drilled hole and remove the plug. 311 #1 Industrial Way – Fallbrook, CA 92028 – USA Phone: (760) 731-1200 Fax: (760) 731-1284 E-mail: firstname.lastname@example.org Website: www.baronscustom.com Included in this kit: (2) Mikuni main jets, (2) pilot jets, (2) titanium needles, (2) clips, (8) cap head Allen screws Revision 2.0 c. With air/fuel screw now accessible, use a flat blade screwdriver to turn the screw clockwise until it seats, then carefully turn it counter-clockwise 3 turns. Refer to final step for assistance in fine-tuning the setting of the air/fuel adjustment screw. • Reinstall the OEM air filter assembly. • Check all vent lines, fuel lines, and linkage for any obstructions or blockage