Mikuni Needle Jet Adjustment

How to adjust mikuni carb on yamaha moto 4. Most 4-strokes are this way. After play with the carb some more it turns out the bike runs well with the jet needle in the rich position. once it is, it will slide right in. The pilot or slow jet is also accessed from inside the float bowl area but is a small diameter brass jet with a screwdriver slot just in front of the larger brass main jet. Tuning and Jetting Mikuni Carbs (vintagebikebuilder. main 140, pilot 42.     If you put 120mm Mikuni mains in then you get a great low/mid range and a lower top end. Offering quick needle jet adjustment, and uses readily available standard Mikuni jets. This is especially important when a bleed type needle jet is used. Mikuni Carb Tuning Manual. Keihin FCR tuning manual. X = The total length of the needle : Y = The measurement from the top of the needle to where the taper starts : Z = The dimension in mm from the top of the needle to the pronounced taper point. The needle jet is next. Mikuni jet needle comparison charts. • Flat Throttle Valve Design. Kaw OEM or Mikuni needle jets are not. The main problem comes from their setup. Consequences: 1. 0 Treatland also sells a 16mm Mikuni for $85 that has a 20mm inner clamp diameter. (6) Assorted Mikuni Main Jets (2) Mikuni Pilot Jets (2) Titanium Adjustable Needles (2) E-clips (8) Cap head Allen screws TOOLS REQUIRED: 10 & 12 MM Wrenches & Sockets Assorted Allen Wrenches Phillips and Flat Tip Screwdrivers Factory Service Manual INSTRUCTIONS: JET/NEEDLE Size & Setting Chart. Replaced the factory carb on my ssr110 with the mikuni 22mm-133. ADJUSTING NEEDLE JET CLIP Step 6 The needle jet controls the amount of fuel from ¼ to ¾ throttle positions. The Needle jets are installed in the Carburetor in one of two ways. ÿ Primaryÿjet. 5 O-0 5E75 1. So, I don't have a 96 needle or a 240 main jet, I will have to order those. These will not make you an expert tuner. We sell Mikuni VM and CV air adjusting screws, slide needles and preload springs. Make sure the washer is the smallest that can be found. No problem to remove the main jet holder that is a fuel pipe up to the needle jet (red arrow) where the needle pass thru. Fit the leaner needle with the clip in the middle notch. 57 Due to the age of the carburetor it may require a rebuild. The needle jet's effect on mixture is limited from. In the case of the primary type, air which comes from the main air jet is mixed with the raw fuel after it has been metered by needle jet and needle. Install the pilot jet (20). Adjust the accelerator starting point so that the pump starts working immediately. Buy Mikuni HSR42 Jet Needle J8-8DDY01-98 Leaner Mixture: Jets & Jet Kits - Amazon. See Worn Needle and Worn Needle Jet diagram. We carry Mikuni needle jets in the 159, 166, 224, 247, 327, and 480 series. Kawasaki H1 500 Carb Kit Part #H1-7276 Price $225. Carb rebuild kit for standard SBN carbs. Comparing these numbers to those in the factory Suzuki service manual is recommended if the service history of the bike is unknown. Mikuni jet needle O-0 is one step richer than N-8. Mikuni used to carry different slides so you don. Rick Sieman walks us through the basic function and set up of one of the most common and time-tested carburetors of all time, the Mikuni round slide. When I was having my bogging problem, my friend said to look at where my needle was set, there are 5 notches and it was on the 4th, he said to move it to the second to lean it out more, bottom line was one of my carbs were plugged up, now I am conserned of this needle adjustment, the sled runs great I dont want to burn it up running to lean, I usually ride from 2500 to 6500 feet if that makes. and if I screw all in, the engine will dies. The needle is in the leanest position when the clip is on the top, and richest on the. 75 out on the brass adjuster screw which also should be between 1-3. No more searching for shims to adjust and tune your carbs. 604-(size) Main Jets, sizes 140 to 240 J8-8DDY01-(size) HSR42 Jet Needles, size 95, 96, 97 and 98, standard in HSR42 is 97. Use only genuine Mikuni jets. The needle jet is next. Adjust the end point for maximum travel. A wide range of tuning components are available to. * There is one adjustment screw on the belt side of each carb, where is the jet needle? * How do I set the idle? It is currently idling at 1100 and should be running around 1800 from what I am told, correct? * Finally, would anyone have factory settings I can try for basis point, to get me on the right track? Thanks again. I think the needle valve seat was worn. When we tuned our Mikuni we tried about ten different main jets, five pilot jets and every clip position on the needle jet. The technicians of Group K intend this document will provide the most current possible fine tuning information for the Mikuni "Super BN" and "I" series, as well as the Keihin CDK II series carbs as they are applied to personal watercraft. Denver formula for 70 degrees at 5300 feet is : 0. Mikuni BSR33 adjustment after overhaul. 5 with K&N filter BMW R100 Mikuni VM34 230 40 P4 6DH4 - 2. : 3) Clogged idle mixture circuit. Although these carburetors were originally delivered on the above mentioned BMW F-650, they are often transplanted onto other bikes and engines so the range that these service kits might fit is much broader. If you look carefully at any needle jet that you have, you will see two sets of numbers stamped on the body (assuming it's a genuine Mikuni needle jet): 1) the upper three digit number identifies which type of needle jet it is e. I will get them fitted so it runs, and also take it to a motorcycle guy for the fine tuning. 5 Mikuni Jet in most cases, to give you a middle of the road so to speak. 5 - 3 turns. The Mikuni Tuning Manual helps make jetting alterations and adjustments an easy matter. Mikuni Carburetor Instructions Always consult a service manual for your particular machine for proper initial mikuni bs25 carburetor uses rubber diaphragm to control the needle jet. Hi spindlehead,i reckon your now spot on with your jet/needle settings. In the case of the Rotax classes using the FN 266 needle-jet and a K27 or K98 needle this would be a minimum main jet size of less than 100, above which the needle and needle-jet would function as designed by Dellorto. In the closed throttle position, the tapered needle shuts off flow from the needle jet. the needlepulls away from the main so the main and needle work together. Proper Tuning of Your Mikuni Carburetor. the needle fits in to the main jet the needle is tapered so one end is larger than the other when you lower the clip it raises the needle and this allows more of the hole (main jet) to be exposed because the needle is thinner. The main jet is screwed into the end of a tube (called the emulsion tube), within the float bowl chamber. Metering Circuits by Percentage of Throttle Opening: Relative Mixture of Common Needle Jets. Most of the newer carbs, along with the higher performance older carbs, have replaceable needle jets, so if yours is looking worn, just go get a new one! You can also do more specific tuning with the needle and needle jet too - there are often options of needle tapers and needle jet diameters. The RS series Carburetors feature a compact design. The manual says it should be 2 7/8 turns out, but it is more like 2 - 2 1/4, to make up for the larger pilot jet. A change of the main air jet will affect the flow of fuel mainly at medium and high speed driving, resulting in change of output power. Use Garage as a guide to what jet you need. Because the engine ingests a fixed volume of air per cycle, the amount of oxygen available per cycle varies with the weather. Carburetor Theory 2. Tuning Tips & Manual Downloads. Denver formula for 70 degrees at 5300 feet is : 0. 090 thousands. 5 turns each… which would be your “bench balancing”. 99 each Includes: Float Bowl Gasket, O-Rings, Carburetor top gasket, Float needle & Seat, Main Jet, Pilot Jet, Adjustment screw, & Spring. That is pretty much what you desribed. Provides the strongest signal for precise and instantaneous throttle response • Float Bowl Vent. As the slide moves, the jet needle goes up and down in the "needle jet", sometimes called an "emulsion tube". For needle shims see fastener Dont see the needle you need below, check carb rebuild kits. Reference: Dellorto PHBL & Mikuni Ty 125 to Dellorto PHBL needle jet holder. It always did with the older carb. I will get them fitted so it runs, and also take it to a motorcycle guy for the fine tuning. I say keep it going and lets here about the needle jet and slide cutaway selection and follow that up with the main jet. The higher the last two digits the weaker the needle (so the 53 is the richest we. Mikuni Carb Picture(View) NOTE: The Hitachi Carbs article found on this website tells about removal, disassembly, tuning, and common problems. We have done our best to display an example to the left. Use @babel/preset-env SeaDoo Dual Mikuni Carburetor Rebuild Kit Needle Seat Base Gasket GTX 1992-1993 to avoid transpiling async/await unnecessarily. 00 (Sold direct only - no dealers on this one, sorry) Kit includes: Custom 5 clip postion, 5 angle needles for a much more exact fuel control. A simpler version exists, most commonly found on small motorcycles and dirt bikes, where the slide and needle is directly controlled by the throttle position. How to adjust the needle as part of the rejetting process by Jets R Us. A tuning kit with jets selected for each application is recommended, which allows us to jet the carbs for your application and include a selection of richer and leanger jets for fine tuning. How to convert your carburetor to E85. 8 size and 2. float type, fixed main jet, side (horizontal) draft carburetor; idle speed and mixture are adjustable; gravity feed. Install the pilot jet (20). Mikuni North America is the primary jet supplier. Looked this part number up in my old parts book and it says that this fits the 32mm Mikuni carbs. The 2-stroke Type 159 (primary) needle jet is standard for most 4-stroke twins using the VM 30, 32, 34, 36mm. Everything else is stock as far as air box, original 26mm mikuni carbs, exhaust. To get to the needle assembly remove the two screws holding the diaphragm cover on and beware of the large spring underneath it. I have a new Mikuni now, the old one did the same thing as yours. You don't get a new one in the carb kit, so clean and refit the old one. If this O-ring is dried out, shrunk or damaged, fuel can pass around the outside of the Needle jet instead of just thru the jets center causing a richer carb fuel mixture. During your 2-stroke carb adjustment, pay close attention to the needle. There are No checkout buttons on this page. Have a Question about Mikuni VM32 Round Slide 32mm Carburetor - Right ? Mikuni 159 Series Needle Jets. The main jet controls fuel flow from 3/4 thru full throttle, fig 5. 5 turns out on the fuel screw. The jet needle controls the fuel mixture in the mid range throttle position which is approximately 1/4 to 3/4 throttle opening. Aylor Engineering. ÿ Same as 166 OEM. 0 AJS/Matchless G80S Mikuni VM26 210 15 P6 5F21 1. The ‘E’-Clip can be raised or lowered on the Jet Needle. * There is one adjustment screw on the belt side of each carb, where is the jet needle? * How do I set the idle? It is currently idling at 1100 and should be running around 1800 from what I am told, correct? * Finally, would anyone have factory settings I can try for basis point, to get me on the right track? Thanks again. During the first ten millimeters of lift, most Mikuni needles are cylindrical - not tapered - and this means that mixture control in this part of the slide lift is performed only by the needle jet. For example: the thinner the diameter of the needle, the more fuel will be drawn through the needle jet. Needle Dimensions. 5 or 15 and it is a little too rich when hot on my 440 with. Dynojet Stage 1 Carburetor Jet Kit With Jets, Needle, Spring And Shim 3145. 3) Jet needle aka Needle - Affects the mixture from 1/4 throttle to full throttle. If you look carefully at any needle jet that you have, you will see two sets of numbers stamped on the body (assuming it’s a genuine Mikuni needle jet): 1) the upper three digit number identifies which type of needle jet it is e. Float height (AKA fuel level & how. Basic Tuning Guidelines. Engine sounded like a V8 but wrong. Tuning Tips. Steve) The needle that is held in place with a circlip and has the two spacers, is the "jet needle". The 6F19 needle. Some adjustments can be made by replacing interchangeable parts. 5 Needle and Seat Part #: 07-410-5. Because the engine ingests a fixed volume of air per cycle, the amount of oxygen available per cycle varies with the weather. The jet needle is a tapered needle that moves in and out of the needle jet. Intermediate –jet needle height adjustment. It pops on decelleration, but still runs good. On this page you will find all currently available parts for the Mikuni BST range carburetors. Regular Price: $14. The speed range in which mileage is usually recorded is controlled by the jet needle and pilot jet. Check them for "oblong" wear - the needle jet orifice starts out round!. 5, needle 6F19 clip on 3rd slot (Australian, Canadian and UK needle) US models use a 6F23 fixed clip position jet needle and a Y-5M needle jet. Dial in the slow circuit and air screw first, then the needle and clip position, then the main jet, and the power jet last. Needle jets are available with different inside diameters. Hey fellas, I ve been playing around with my Mikuni carb to try and get a good result. Clogged air cleaner. During your 2-stroke carb adjustment, pay close attention to the needle. Oils and plugs changed yearly along with Sta-bil, etc. Jetting Examples. The needle jet and jet needle control from 15% to 80% of the throttle opening and the main jet controls 60% to 100%. Online Shop » POWER SUPPLY » SPARE PARTS FOR CARURATORI Dell'Orto » 09436225_33 NEEDLE VALVE DELL ORTO PHBL MISURA 225; 09436225_33 NEEDLE VALVE DELL ORTO PHBL MISURA 225. 002-990 Velocity Stacks Velocity stacks improve the air flow into the carburetors to. 5 Works perfect. I am running a 25 pilot and 330 main jet; 166 Q2 needle, 6DP1 jet needle. The Jet ski Carb for the 550 Jet Ski is a Mikuni 38 mm Carburetor. Needle jet 249 0-0. We will work with you until your BMW runs like a top. I have a question regarding tuning if you can help, the bike (Triumph Bonneville T140V 1978) is fitted with VM32 Mikuni carbs and it's not running as well as it should. Both parts improve the original Mikuni design. An incorrect jet needle or pilot jet for a particular tuning set-up or altitude can reduce fuel mileage. 0 BMW R75/5 and R100 Mikuni VM32 200 35 P2 6DH3 - 2. one millimeter apart (. See Worn Needle and Worn Needle Jet diagram. Idle Adjustment Screw raises or lowers throttle slide height to control engine idle speed. Where as Keihin Carbs its recommended (if necessary) you change the Needle first. I tried one, it sit hard if it should be pressed out from inside when the main jet holder is out. To get to the needle assembly remove the two screws holding the diaphragm cover on and beware of the large spring underneath it. I think the needle valve seat was worn. As the slide moves, the jet needle goes up and down in the "needle jet", sometimes called an "emulsion tube". A wide range of tuning components are available to. comes with a 30 idle jet and a 100 main jet. It includes the needle jet, jet needle, and, to a lesser degree, the slide. Mikuni Carburetor Tuning Manual from Sudco. To order electronically: click on the Order button for the part you want to place in your shopping cart. N–5, Q-3. 5 and air jet 1. The Power Valve circuit needs to have its flow increased also to bring the primary up to about 35% at WOT. The needle has 5 notches. Oils and plugs changed yearly along with Sta-bil, etc. one thing you need to watch is the air main jet (which is usually the largest available) and the slow air jet (which you'll likely need to change to attain the proper idle mixture). So, I don't have a 96 needle or a 240 main jet, I will have to order those. The 40's are from the last oil cooled 1100R's, the M and N ( and 1100W's. The needle effects mostly the acceleration and the transition from the pilot to the main jet. 8) available in the following sizes. In a previous post, " Carb Jetting Basics " I explained why jetting is important, what factors affect jetting, and how to do basic jetting adjustments. if there any possible the pilot jet was broken or the size is incorrect due imitation product? or maybe i need to setup the float more lean? thank you for the reply Matthew. Please send corrections, comments, additions, etc. Yes dropping the needle into the needle jet as you describe will lean out the mixture, from memory snatched out of a dellorto carb tuning guide this affects mixture from around 1/4 throttle up to just under full throttle (on CV carbs the top end depends on where the engine vacuum has lifted the needle slide to). TTR CARBURETOR CARBY CARB 50CC MIKUNI TTR50 MAIN JET NEEDLE FOR YAMAHA TTR 50. Final set up is a: #25 pilot jet, a P4 needle jet, a 6DH3 needle set in the middle notch (could drop it a notch, but doubt if I will), and a #200 main jet. Note: If the adjustment screw is in the front of the carb, it is a fuel screw and not an air screw; it is adjusted the opposite of the air screw. This is especially important when a bleed type needle jet is used. Main jet, metering needle, air/fuel screw, needle and seat and gasket for needle and seat. The bleed type doesn't appear to offer any advantage, and not only will it need larger sizes than the 159 but also affects needle taper. It seems to make more sense when you (Indy600) explain it then when reading it in a tech book or tuning manual. 5 Needle and Seat Part #: 07-410-5. I haven't left the gas on since changing carbs but gas does not run out of my air vent tubes now when I stand the bike up. 1 x Carburetor Kit as Pictured. 3 slide cutaway, 106 needle jet and increased main jet from 220-320-350. It is recomended to first change (if necessary) your needle jet on Mikuni carburetors. Replaced the factory carb on my ssr110 with the mikuni 22mm-133. I have a question regarding tuning if you can help, the bike (Triumph Bonneville T140V 1978) is fitted with VM32 Mikuni carbs and it's not running as well as it should. Mikuni Needle And Seat 786-35015. 300" long and has a 4mm/. I am not sure how to adjust the air gap on the pick. In this kit is the bowl gasket. Needle Jets Two Basic Types of Needle Jets Primary Type Bleed Type On the following application chart, it is noted that certain needle jets require a specific type of main jet because there aretwo types of main jets (4/042 & N100/604) that have different fuel flow rate characteristics. The “balancing” would be accomplished when the carbs are on the bench, by turning the needle jets all the way in, then back out 2. A mystery for sure. All tuning components manufactured by Mikuni will have the famous "square within a square" tooled into the part. To lower or raise the needle, take off the top cap, loosen the screw holding the jet needle in position. Dynojet Stage 1 Carburetor Jet Kit With Jets, Needle, Spring And Shim 3145. Again Coffee Brown, is what you are looking for. Jet Needle: The jet needle works the same way as the Mikuni VM carbs. 50 each Meters the air flow through the passage to and into the needle jet. With the air screw 1. In the Rotax class we have two needles available the K27 and the K98. 6F5 Jet Needle - (Fits: Mikuni VM Carburetors). The problem is that I don’t know what size jets and needle to use. In order for this to work your browser must use frames and you must start at the Old Britts Home Page. The only real thing you need to know to put things all together is the needle jet (emulsion tube). It consists of two proprietary needles, a spare needle clip, detailed instructions with a jetting guide and a selection of main and pilot jets. Main jets take over from there. These settings were provided by the Victory Library "Mikuni Tuning for British Twins" author Jeffery Diamond www. Throttle Slide Cutaway- 1/4 THROTTLE to 3/4 THROTTLE The Mikuni VM. 'You may also find that there are other Mikuni needle jets that though having a different series number stamped on them and not listed on this page, are in fact identical in dimensions to another shown here and thus interchangeable, but you must read each products description to be sure it is compatible especially in regards to the correct main. Not to much force to be used either since it look fragile. A large selection of Genuine Mikuni large round main jets. This service is ideally suited for individuals that have purchased new or used VM carburetors from a source other than Rocky Point Cycle and want to get them dialed in for BMW brand motorcycles. Changing the main jet size will adjust the top end of the operating range from half to full throttle. Needle Jets for Spigot Mount Carbs. Carb is clean and float level is correct. Needle jets are available with different inside diameters. A mystery for sure. When tuning your Keihin Carburetor please follow the recommened guidelines. My question, is there a need to rejet the carbs? Do you think it needs more gas? Would adjusting the jet needle be ok? Maybe try the #4 position on the jet needle?. Main jet, metering needle, air/fuel screw, needle and seat and gasket for needle and seat. He has over 100 HP in his engine and has this carburetor working well. Oils and plugs changed yearly along with Sta-bil, etc. Needle jets allow a great way for tuning carb at 1/4-3/4 turn throttle. com) Adjustment Screw Location. If you copy our setup you may or may not see great results. Mikuni and custom needle jets. Carburetor tuning must be done to provide max power without overheating the 2 stroke engine. I haven't left the gas on since changing carbs but gas does not run out of my air vent tubes now when I stand the bike up. Tuning Tips. Mikuni jets are said to be ten sizes larger than Teikei, so a #138 Mikuni is the equivalent of a #148 Teikei. 5 in stock form, and this should not be modified for any setup. Replaces failed jet block gasket, and fuel needle seat O-ring with spare. * There is one adjustment screw on the belt side of each carb, where is the jet needle? * How do I set the idle? It is currently idling at 1100 and should be running around 1800 from what I am told, correct? * Finally, would anyone have factory settings I can try for basis point, to get me on the right track? Thanks again. Fits: XS/TX 650's (1970-79) with Stock Mikuni BS38 CV Carbs. Other jets such as dynojet use a different numbering system. " Carb Guide In PDF Format. I came in and reread my Mikuni tuning book. They cost $3. last night i was try using 17. mikuni fuel pump for 16 horse vanguard motor. The throttle valve controls 0% to 35% of the throttle opening. These will not make you an expert tuner. So you know you can trust Mikuni carburetor jets & needles to keep your carburetor mixing your fuel and air intake at peak performance. Yamaha VXR Wave Blaster Wave Raider XL700 XL760 Dual Mikuni Carb Rebuild Kit 685867151500 DUAL Mikuni SBN-I Carburetor Rebuild Kit Yamaha GP 800 XL XLT Waverunner Needle-Search Home Pricing. Also, needle jets are. 5 turns out. I am running a 25 pilot and 330 main jet; 166 Q2 needle, 6DP1 jet needle. ENGINE DOES NOT DEVELOP FULL POWER OR MISSED ON ACCELERATION. tion of the needle is within the needle jet and main system fuel flow is controlled by the size of the needle jet. For Mikuni VM26SS carburetors. Mikuni choke adjustment 20 I've reset the float height without removing the carbs,what a [email protected] of a job trying to hold the needle jet in place whist re. The one at the bowl end is the main jet. Throttle Slide Cutaway- 1/4 THROTTLE to 3/4 THROTTLE The Mikuni VM. A large selection of Genuine Mikuni large round main jets. Needle Jets P6 Needle clip position 3rd from top I'm in Toronto so about 250 ft above sea level. Mikuni N102,221 Main Jets. It made my bike reliable, no more cranking the throttle to keep idle to warm up and it increased power and speed. Mikuni TMX Needle Tapers Starting Point - Black Line: Mikuni TMX 6BFY44-73 Needle Straight Diameter Marked with Sharpie: 2017 KTM -TMX Late Model V2 Inlet- Needle Jet is Removed: TMX Late Model V1 Inlet: 2017 KTM -TMX Late Model V2 Inlet, Needle Jet and Shroud: 2017 KTM/Husky TMX Mikuni Needle Jet Has 3 Bleed Holes: Mikuni TMX Jetting for low. There are No checkout buttons on this page. user guide pdf Mikuni Carburetor ID Guide Mikuni does not offer a rebuild kit for these carbs. Most of the tuning for this range is done to the jet needle, and not the needle jet. Once the throttle is opened far enough, the jet needle is pulled high enough out of the needle jet and the size of the hole in the main jet begins to regulate fuel flow. KRS-005 for RS38 and RS40 Order No. Carb tuning help - mikuni flat slide remember that half throttle won't be the main jet-- it's the needle jet that the needle goes in and out of. We also have custom needle jets in the 224 series from DDO - EE5. Top Left side - This is a picture of the needle jet area of an emulsion tube from a stock 38mm CV Mikuni carb as installed on Ducati, Yamaha TDM/TRX 850, YZF750, FZR1000, etc. Mikuni Flat Side Carb Tuning for Dummies Needle/Jet System- 1/4 THROTTLE to 3/4 THROTTLE 5. Hi spindlehead,i reckon your now spot on with your jet/needle settings. To order electronically: click on the Order button for the part you want to place in your shopping cart. Install the main jet into the needle jet holder (17) and tighten securely; then install the needle jet holder assembly into the carburetor and. They cost $3. keihin carburetors cb750 115 jets. The carb code I am referring to is on the body somewhere. Needle Comparison Graph. Produces the optimum air and fuel mixture flow at all RPM. This will be the correct fuel level. Mikuni Round Slide VM Series Carburetor VM44-3 Carburetors come complete with lever You search Auto repair manual PDF mikuni bs 34 ss tuning manual. If you are using the XLH needle, place the jet needle into the slide without using any washers. how to rebuild a mikuni carburetor. The needle jet on the VM34SS is not standard Mikuni fare, it's a two piece thing with part stuck up inside the carburetor. Have a Question about Mikuni VM32 Round Slide 32mm Carburetor - Right ? Mikuni 159 Series Needle Jets. High speed - Main jet size change. Replaces failed jet block gasket, and fuel needle seat O-ring with spare. The last factor in the main system is the Main Jet. Put the C lip in the middle setting to start. I haven't left the gas on since changing carbs but gas does not run out of my air vent tubes now when I stand the bike up. Jet Needle - this controls the fuel when you open and close the throttle (between 20 and 80 percent power) Needle Jet - this is what the jet needle pops in and out of (between 15 to 60 percent of throttle _____ Main jet tuning: perfect air fuel ratio is 12. The needle jet is the main fuel passage to the main bore (venturi) of the Mikuni carburetor. 005 washer under needle 2 richen. Correction: Mikuni replace needle jet with next richer and test again. 5 and still tuning so I got a 25 just in case. If improvements appear in one direction of adjustment but perfection is not achieved whilst having reached the end clip on the needle, then you will need to install a richer or leaner needle if available or else a corresponding needle jet. When we tuned our Mikuni we tried about ten different main jets, five pilot jets and every clip position on the needle jet. If you copy our setup you may or may not see great results. The Sudco/Mikuni tuning manual provides most of the necessary information regarding the maintenance and tuning of Mikuni carburetors. Raising or lowering the jet needle has no effect on fuel mileage below about 70 mph. Throttle Slide Cutaway- 1/4 THROTTLE to 3/4 THROTTLE The Mikuni VM. untill you set-up carb proper just use 2 only bowl screws to make it a bit easy , the needle itself has nothing to do with under less than a 1/4 throttle the 1st section of throttle is handled buy the idle jet, needle is for about 1/4 throttle & up , needle& needle jet+ main air bleed & main jet size work the later throttle openings ,. Best selection and great deals on Mikuni Carburetors. The taper of the needle determines the amount of fuel. Mikuni used to carry different slides so you don. Mikuni round slide tuning baseline Moto Guzzi V7 Sport, 750 S, 750 S3, 850 T, 850 T3, 850 T3 California, V1000 I-Convert, V1000 G5, 1000 SP, Le Mans, Le Mans II, Le Mans CX 100, Le Mans 1000, 1000 SP III, 1000 S, California II, California III, California 1100, California Jackal, California EV, California EV Touring, California Aluminium, California Titanium, California Special, California. An incorrect jet needle or pilot jet for a particular tuning set-up or altitude can reduce fuel mileage. The needle is broken into 3 main functions; Diameter, Length, Taper. These needle functions have a large effect on the carburetors jetting from ¼ to ¾ throttle. You insert it from the top like. This Mikuni HSR carburetor kit is designed to be a bolt-on application, and as such, is set-up and jetted properly for most applications. Timing is good. Needle jets have different size holes in them. The needle jet pipe does not adjust the mixture, that is the function of the main nozzle. For Carbed engines, you need to up the size of the jets to flow about 20% more for the primary, and 35% more for the secondarys, and tune from there. VERY IMPORTANT! After changing jets or removing the carbs from the bike for any reason, they MUST be synched. pilots and mains are SIMPLE. main 140, pilot 42. Correction: Mikuni replace needle jet with next richer and test again. As far as the needle setting goes, ideally you should strive to find the main jet size that allows the needle to best operate in the center position. This section features the PWK exploded views just to let you understand where the tuning components are located. Mikuni Round Slide VM Series Carburetor VM44-3 Carburetors come complete with lever You search Auto repair manual PDF mikuni bs 34 ss tuning manual. Changing the STRAIGHT DIAMETER (D) will change the calibration in the transition range from the SLOW circuit to the MAIN circuit (1/8 to 1/4) throttle. VM28/486-(size) Pilot Jets, sizes 15 to 50 N100. When cleaning carb the pilot jet should be removed and "reamed out" with a fine wire. The needle jet and jet needle control from 15% to 80% of the throttle opening and the main jet controls 60% to 100%. Mikuni Viton Needle & Seat. Barons reuses the stock #35 pilot but there is an improved performance difference when using the #40 pilot jet. 43 – Length from tip of needle to start of taper, 43 mm (need to verify) 73 – Diameter of cylindrical portion of needle 2. Other jets such as dynojet use a different numbering system.