Mikuni Main Jet Size Chart

Drilling jets and carbs are quite simple if you go in step sizes with a hand pin vise. Main jets are available in sizes #110-#134 and the pilots available are #38 through #43. 0mm Slot head Meters the air flow through the passage to and into the needle jet. Sudco can “Special Jet” any Mikuni Carburetor for your particular application. Jet Kit Asssortment. Please remember that sometimes the stock OEM jetting will work just fine, other times you may have to make an adjustment, so use our suggestions below as a guide to help with your jetting problem. DJ Style Main Jet. Knurled handle for easy grip and rubber cap with jet storage in head. High speed - Main jet size change. The main jet. 5 with a #62. To find out the correction main and pilot jets, multiple the correction factor and each jet size. Mikuni Primary style Mikuni Bleed style Keihin style. It's also Mikuni type 4/042. Remove the four screws that hold the float bowl in. 02598" #71 66 jet. Have a Suzuki 85 GS5550L with two duals mikuni carbs. The following is a chart showing jet size, equivalents, and fuel flow. Fits: XS/TX 650's (1970-79) with Stock Mikuni BS38 CV Carbs. 5 (Stock Main Jet #105 & Pilot Jet #20. 0mm Slot head Meters the air flow through the passage to and into the needle jet. and maximum power is developed. Share Thread to do anything but change the main jet but still pretty easy. 95 JavaScript seems to be disabled in your browser. Mikuni VM Carburetor #35 Pilot Jet. MIKUNI JET PART NUMBERS Main Jets JetNumber PartNumber 122. 110 Mikuni Pilot Jets: N224. Lowering the clip and raising the needle makes the mixture richer. BBR Motorsports is the industry's premier adult four-stroke playbike performance technology company. A post in the Performance forum by #CrazyWayne™ rocks. Using the altitude/jetting chart it is best to also order the 60's main jets kit so you can install the #63 jet if you are at sea level, or the #60 jet if you are closer to 4000 ft above sea level. MIKUNI JET PART NUMBERS Main Jets JetNumber PartNumber 122. Mikuni Jets & Springs for PWC Carburetors Carburetor Needle & Seats SBT Rotary Valve Parts for Sea-Doo SBT Reed Sets SBT Fuel Injectors/Filters SBT Fuel / Primer Line NGK Spark Plugs SBT Primer Kits Electrical Accessories BlackTip Jetsports. The chart also has jetting and needle adjustment specs from the oem specs book that should help with tuning. ENGINE DOES NOT DEVELOP FULL POWER OR MISSED ON ACCELERATION. Incorrect use of choke. Avoid installing jets that are too rich as this will create a sluggish feeling at full throttle as well as contribute to plug fouling. THE TMX SERIES CARBURETORS ARE AVAILABLE IN 35MM BORE SIZES FOR 125CC RACE ENGINES, AND IN 38MM BORE SIZES FOR USE IN 250CC RACE ENGINES. I have a fantastic Snap-On set which i use every day to check jet sizes on old carbs. e jet diameter expressed in mms i. Kit Contains: 2 slide needles with clips, 2 pilot jets, 4 main jets (2 sizes), 1 Drill bit to modify slide, Instructions for tuning with various Exhaust & Carb/Intake setups. Spanky's Jetting Guide: A correctly jetted carb makes a tremendous difference in the torque, midrange pull, top-end pull, and over-rev of your engine. (You need to use the STP jet size as the base). dual 44 phh mikuni carburetors. A main jet size of 350 would be multiplied by 0. The other 'pilot air jet' is called PAJ2,,, meaning 'pilot air jet number 2. 24-26mm Pilot jet Main jet Spigot for slot in needle jet The needle clip may be moved. 0 Idle RPM +/--200 1500 Cooling Liquid Cylinders 2 Ignition Timing _BTDC @ RPM 18_ @2500 +/--500 w/tps Ignition Type Digital Oil Injection ves Spark Plug Champion. Flow rates based on size markings of Mikuni and DynoJet jets are not comparable. Mikuni publishes a comprehensive tuner's guide available here. Currently the jets that came with the carbs were for a gsxr750 so they are on the small size Just wondering what other people are using with a similar setup? GPZ1100 converted to Mikuni RS34 FS jetting - KZRider Forum - KZRider, KZ, Z1 & Z Motorcycle Enthusiast's Forum. Ralph Spencer. Set the main jet first for correct running at wide open throttle and max speed. The size of the jet is how much fuel it allows to pass. Main jet size numbers do not all yield the same flow for different style jets, ie, #100 Large Round Reverse has different flow than #100 Large Hex. the appropriate Honda Shop Manual to replace the main jet inside the carburetor with the appropriate size. If you find this hard to believe, use the main jet test in the Mikuni manual to see for yourself. eg: 150, 155,160,etc. If your stock main jet is a 100 (stock size in a 22mm Mikuni) you will find this jet size falls between the #62 & #60 drill bit. DO NOT ACCEPT SUBSTITUTES. 5 in stock form, and this should not be modified for any setup. These are the jetting recommendations for S&S carburetors for various engine sizes. Enter your search keyword. 92 and the pilot jet size would be 36. 5 out Main Jet 178 2000 Pilot Jet 45 Needle STOCK Clip Position 3RD Air Screw 1. Look for a milk coffee colour on the porcelain, use a used plug that has already coloured up, (note KX 85s and 100s will be a lot leaner than the plug chop looks, be careful. 110 Mikuni Pilot Jets: N224. 95 Quantity in Basket: none Carb to air tube connecting rubbers 30mm-->34mm Mikunis, pair, for Mikuni 30 - 34mm round slide or flat slide carbs. The numbered bit set that I bought is too small for drilling main jets. A pilot jet size of 40 would be multiplied by 0. Accelerator pump jets $8 per pair. 5 in stock form, and this should not be modified for any setup. If the best position is as much as three turns open, the jet is to big. Part# 122-132. 188 type needle jet? My chart lists that. Increase the main jet size 2 steps at a time. The OEM Constant Velocity Carburettor introduced by Harley Davidson on its Sportsters (1989) and Big Twins (1990) is actually a damn good piece of equipment, capable of flowing enough CFM of air to feed modified 90+ HP motors while giving nothing away to aftermarket carbs by S&S and Mikuni. If you are located 1000’ or above sea level - refer to the Main Jet Conversion Chart. a 3326 main jet, other sheets list the 376/100. I found this Jet conversion chart. While true for a stock machine, as you add mods the temp range that a main jet size works best for may be as little as 20 degrees F (for example: 310 mains for 40-60 degrees F, 300 mains for 60-80 degrees F, etc. This is very handy when using jetting charts. Below is a more comprehensive and definitive guide to jetting your carb. 5 out Main Jet 178 1999 Pilot Jet 42 Needle STOCK Clip Position 2ND Air Screw 1. If it's lean and you need to increase the size of your main jet, drill the jet out with the next size larger drill bit, which in this case is the #60 bit. Mikuni "VM" Factory Carb Specs Jetting Specs ~ Carb Body Specs Throttle & Cables, Fuel Line, Reed Valves ~ ~ ~ JETTING Carb Size Main Jet Pilot Jet Needle Jet Jet Needle Air Jet Slide Cutaway 16mm #70 #25 165­O­8 3DJ3 None 2. Dynojets have a machined flat surface. The 26mm are an oddball as they come with 4-stroke jets, these can be modified but MB recommends the 25mm size. 60 You save 14% Pro X N424-21 Series Keihin Pilot Jet $3. OEM Replacement This part is aftermarket equipment designed to replace the original manufacturer's part numbers specified here. The best destination for OEM, Aftermarket, Tires and Gear for your machine!. For example, a Dynojet 152 main jet is actually a Mikuni 142. The chart below lists the inside diameter of the needle jet in millimetres, ie an N-6 is 2. It's a 2 minute call that could save you $100 or more!. To find out the correction main and pilot jets, multiple the correction factor and each jet size. Install the correct main jet as indicated in the chart in the upper right corner of the page. Lowering the clip and raising the needle makes the mixture richer. The numbered bit set that I bought is too small for drilling main jets. This saves a bunch of time when dyno tuning a bike. #CrazyWayne. main jet fell out while cleaning out carb and don't know where it goes. retest with a larger size. Change jet size by 2 or 2. 8mm Slot Head14mm Length Plain, unbeaded nose Ø3. The needle - Dynojet or Mikuni - has very little effect. Is there a chart that states what the actual hole diameter is based on the jets size. All numbers in this site assume a mikuni main jet. Last year Polaris listed a part number (#3130150) for a 530 main jet size, but now for 2002 all jetting charts take you from a 500 main up to a 540 main, or they will specify a new jet size with an “N” designation. Eg: 100,102,105,108,110. any recommendations on jetting for this sled. Didn't find what you are looking for? We have millions of parts and accessories not listed on our site available from our vendors. Spanky's Jetting Guide: A correctly jetted carb makes a tremendous difference in the torque, midrange pull, top-end pull, and over-rev of your engine. See NexTag Sellers' Lowest Price! Mikuni Jet Needle Chart. 5 mains & needles on 4th notch down. A-BAX Precision Engineering Ltd brass main jets for Keihin CVH carburettors, used on most big twins. However, we may be able to help you avoid the general problem of "wrong" combinations with the information found in the web pages assigned to the links at the top of this page. 0mm Thread length 50-200 (Δ 5) 210-500 (Δ 10) 520-720 (Δ 20) H5-N151067-A-SIZE Special Order M5x0. The fact is you cannot directly interchange the jets for a given size. These data are calculated depending on the weather conditions and the engine configuration introduced in the other tabs. The main jet does not effect the jetting for starting and idling. The 520 was an accidental overlap in the two numbering systems. 067 non-bleed pilot jets. My combat with 32mm ports started with a 440 main jet and the verdict was that it ran too lean. Use a richer main jet and/or needle setting. Note that no altitude compensation is needed on the pilot fuel jet since our elevation is less than 6000' a-s-l. Look through the hole in the new main jet to make sure there is no debris blocking it. Find great deals on eBay for mikuni main jet 80. The main jet screws in next and holds the emulsion tube in place. 0mm Thread length 50-200 (Δ 5) N100604-SIZE…. Accelerator pump jets $8 per pair. Obviously the needle jet range is from N-0 as the leanest up to R-9 as the richest. Description VM, TM, RS, HSR OEM TMX, BSR Rhino Bleed Type. Whatever air kit you decide to purchase or if you are jetting the carburetors because of a new. Dennis Kirk stocks carb, jet and intake parts from all the major manufacturers, such as Dynojet, Mikuni and Kimpex, as well as some quality players you may not be familiar with. Main jets for motorbike carburetors (made by Dynojet - USA) CJ main jet. More Horse Power – Excellent Running Quality; Optimizes Fuel – Easy Installation. The CVP Rejet kit is designed for unmodified Harley CV carburetors and riders seeking to "Jet it and Forget it". Main Jets are sized incrementally by 5, so if your stock jet was a #175 the next size larger will be #180. My combat with 32mm ports started with a 440 main jet and the verdict was that it ran too lean. NJ=Needle Jet. The bike starts and runs but after a few seconds starts to pop, and miss. The HSR45 has a number 175 and the HSR48 a 190. (You need to use the STP jet size as the base). As far as size goes, 26mm is best for a 250cc street bike. Keihin Jets are sized in steps of 2 and 3. 5 main 42-486 #20 pilot 42-495 #155 main 42-487 #22. you need to under stand that just comparing the size of the hole doesnt mean everything. It is running fine at idle to 2/3 throttle, but try going full throttle and it sputters like its running out of gas. 5 But if u have aftermarket exhaust and air filter u can use #45 What carburetor is on a 1999. 5 turns out from seated. You should then convert your jetting to the baseline 1. thousandth of an inch diameter that the jet actually is for example, {ie. When the operating altitude of the engine will be 2000 feet higher than your normal altitude, you'll need to insert a jet one or two sizes smaller than the size currently installed in the carb, which reduces the amount of fuel entering the engine to match the reduced level of oxygen in the air. NOTES For Mikuni, Amal, or Keihin HEX STYLE Main jets that are M6 or 1/4" In size. This saves a bunch of time when dyno tuning a bike. to jet his or her own carburetors. The Jet Needle enters into the top of the Needle Jet and the Main Jet screws into the bottom. If the position of best idle is less than 1/2 turn open, the idle or pilot jet is too small. 044" is equivalent to a Mikuni #103. MIKUNI MAIN JETS EXPLAINED or HOW I SAVED BIG BUCKS JUST BY LEARNING THIS STUFF OK folks, here's the full meal deal on Mikuni main jets. Of course it maps jets above our applicable range. Get free shipping, 4% cashback and 10% off select brands with a Gold Club membership, plus free everyday tech support on aftermarket Mikuni Carburetor Jet Kits & motorcycle parts. The stock size was a 150 Mikuni jet, but these say, very clearly, 97. DJ Style Main Jet. For twin carburetor models such as Triumph Bonneville or BSA A65 you would want to use a P26-130, comparable to an Amal 190 main jet. On a 850 Norton for a SINGLE Mikuni VM 34mm dia, use pilot 30-35, throttle slide 3, needle jet type 159, needle jet size P-4, P-6, needle 6DH3 or 4, Main 260, air jet 1. 05 mm in diameter and a 120 jet has a size of 1. THE TMX SERIES CARBURETORS ARE AVAILABLE IN 35MM BORE SIZES FOR 125CC RACE ENGINES, AND IN 38MM BORE SIZES FOR USE IN 250CC RACE ENGINES. I started by refitting the carburettor and doubling the size of the jet. Keep this in mind when using this chart. Mikuni Needle Information. Find great deals on eBay for mikuni needle jet and mikuni main jet. Since the pilot/slow jet is supplying fuel at wide open throttle we always recomend starting with the slow/pilot jet. SIZE Main Jet Slow Jet Jet Needle Thr. If you are on the trail and don’t have the right main jet, try raising the needle by lowering the clip. 92 and the pilot jet size would be 36. the motor is from a 94 zr 700. We took some pics and i figured i would post this in case anyone else needed to know how to do it. Main jet=94,Pilot jet=40. from the threaded end through the orifice and. In the end it wasnt as useful as I would of thought, My recomendation is to use keihin jets and buy a bunch so you can play around with them. Accelerator pump jets $8 per pair. Available from size 74-150 in increments of 2 and from size 150-210 in increments of 5. Bidragslämnarna hävdar att bestyckningen fungerar - Bra i gasen tar inget ansvar!. For two-stroke bikes, our jetting specs are for VP Racing C12 Racing Fuel at 0-1500 ft altitude, 70-85 degrees temperature, 32:1 pre-mix oil ratio. When the operating altitude of the engine will be 2000 feet higher than your normal altitude, you'll need to insert a jet one or two sizes smaller than the size currently installed in the carb, which reduces the amount of fuel entering the engine to match the reduced level of oxygen in the air. 5 main 42-488 #25 pilot 42-497 #160 main 42-489 #27. ) Keep checking the plugs after driving it for a few minutes (Do not let it idle when checking the spark plug color for the main jets. Super G (2 1/16") Engine Size 88-93 CID 95+ CID Idle Mixture 3 3 Intermediate Jet. !!!!! The jet number is linear dependent from the fuel flow which means a #120 main jet has 20% more fuel flow compared to a #100 jet. Nicholson's book says "The monobloc and T. Used to modify GT750 Suzuki CV carbs for anti-surging (#0. Main Jets are sized incrementally by 5, so if your stock jet was a #175 the next size larger will be #180. Shop for Fuel and Air Intake Systems, like Keihin 99101-393 Series Main Jet at Rocky Mountain ATV/MC. Too lean will cause surging, counter this by turning in the fuel screws out in half turn increments. Condition New. Keihin's numbers are based upon the area of the jet, which means a 200 will flow twice as much as a 100. His is a '99 and mine is an '87. These settings were provided by the Victory Library "Mikuni Tuning for British Twins" author Jeffery Diamond www. Remove the jets and insert a smaller/larger set based on the vehicles operating altitude. © 2017 Boyesen Engineering. As a guide the chart indicates equivalent sizes based on the diameter of hole in the jet. 94 x 158 = 148. Question, I am swapping a Keihin carb for a Mikuni carb, what jet do I use? The table below may give a place to start. I have a brand new Mikuni VM38 installed. Find great deals on eBay for Mikuni Round Main Jet in Intake & Fuel Systems. 5 main 42-488 #25 pilot 42-497 #160 main 42-489 #27. A-BAX Slot Jets for. 044" is equivalent to a Mikuni #103. 50 per pair. Should I rejet or try to find a stock air cleaner setup and see if that fixes the problem. 5 for every 1500 ft or 500 meters of elevation 3. KN102221130. On round-slide carbs, this is the most direct route for the fuel, but it requires a lot of vacuum to work. After weeks of tunning on mine I got one (posted in my gallery) it showed a bit lean at low rpms and a bit rich at high rpms. 5 for fine adjustment by 5 for coarse adjustment 2. The standard main jet fitted to the HSR42 is a number 160. The 520 was an accidental overlap in the two numbering systems. If your plug is white it probably does mean that u are running lean and u will want to go up in your main jet size. Incorrect use of choke. - Decrease main fuel jet size by 2 sizes per every 2000' above sea level. Current Sizes: 105, 110, 115, 120, 125, 175, 185, 190, 195, 200, 210, 220, 230, 240, 250, 260, 410, 420, 440, 450, 490, 500 N. The Main Jet is located inside the float bowl and is screwed into the bottom of the Emulsion Tube in the center of the carburetor body. Main Jet, Jet Needle, Pilot Jet (lesser extent than before). Motorcycle Carburetor Jet Size Calculator. List of part numbers that are compatible with the Kimpex number :. Mikuni Jets & Springs for PWC Carburetors Carburetor Needle & Seats SBT Rotary Valve Parts for Sea-Doo SBT Reed Sets SBT Fuel Injectors/Filters SBT Fuel / Primer Line NGK Spark Plugs SBT Primer Kits Electrical Accessories BlackTip Jetsports. the 30mm fits in the oem 28mm boot just as the 28mm fits, nothing to it, as for flat slides, i know nothing about them. Charles, Illinois, 630-513-9700. Get that Cafe Racer of Bobber jetted properly for your exhaust and intake and hit the ton that much faster! $2. Use with 6 mm Hex-head main jets. 83 Cr250 Jetting. Keihin's numbers are based upon the area of the jet, which means a 200 will flow twice as much as a 100. com and click on Shop Manuals. Using a flathead screwdriver, screw the pilot air jet in until it is fully closed, while counting the number of turns. In the end it wasnt as useful as I would of thought, My recomendation is to use keihin jets and buy a bunch so you can play around with them. Remove the OEM main jet and replace it with a Baron’s genuine Mikuni main jet. This jet allows air into the emulsion tube to mix with fuel being drawn up from the float bowl. 0mm Length 5. you need to under stand that just comparing the size of the hole doesnt mean everything. To find out the correction main and pilot jets, multiple the correction factor and each jet size. 5 with a #62. Look through the hole in the new main jet to make sure there is no debris blocking it. The following jetting guide will start you off in the right direction. is it a genuine mikuni jet? if not,throw it away. I think Mikuni's numbering system is based upon the diameter. If not in stock 2/3 days delivery. What main jet will you need? J 2 = (94 / 100) x 158 = 0. Sudco can “Special Jet” any Mikuni Carburetor for your particular application. If it's lean and you need to increase the size of your main jet, drill the jet out with the next size larger drill bit, which in this case is the #60 bit. On a 850 Norton for a SINGLE Mikuni VM 34mm dia, use pilot 30-35, throttle slide 3, needle jet type 159, needle jet size P-4, P-6, needle 6DH3 or 4, Main 260, air jet 1. Below is the information you will need to provide our Carburetor Specialist Technicians so they can provide you with the correct carburetor and jetting. MIKUNI VM TM VMX 160 MAIN JETS - 14 SIZES - $480+ RETAIL 4/042. Carburetor Jetting; Carburetor Jetting. 052 and no/go at. Yep, the stock main jet is rich. The 520 was an accidental overlap in the two numbering systems. Whether you're replacing worn or clogged jets or if you are recalibrating the carburetors for performance, the original Mikuni jets offer unmatched flow and performance. Mikuni is pretty much like reading greek for me, always been used to keihin numbers. Dynojets have a machined flat surface. 22mm mikuni carburetor jet kit. The 26mm are an oddball as they come with 4-stroke jets, these can be modified but MB recommends the 25mm size. Uneven Jet Sizes - Before you embark on re-jetting your pwc, you would be wise to disassemble the carbs to determine the exact jetting of each individual carb. ) # 148,150,152 main jets Bandit 1200 1996-2000 Mikuni BST36SS Main Jet Size Pilot Jet Size. the 30mm fits in the oem 28mm boot just as the 28mm fits, nothing to it, as for flat slides, i know nothing about them. Your local shop should have just about every jet size that you can think of, especially a dealer. I went with the fmf’s recommendations on jet sizes since it has a fmf gold series exhaust and vforce 3 reed valves but noticed the flat spot (main jet was a 330) so ive bought a 340 and a 360 main to try out, I went straight for the 360 and a bit stumped now as the flat spot is still. Keihin's numbers are based upon the area of the jet, which means a 200 will flow twice as much as a 100. the Keihin vs DynoJet vs Mikuni sizing charts found on the internet (if correct) actually imply that NONE of these manufacturers size their jets exactly by diameter. Didn't find what you are looking for? We have millions of parts and accessories not listed on our site available from our vendors. Timing is spot on at 2. Mikuni Style 18mm 2 Stroke Carburetor Main Jet #85 Fits E-Ton Impuls TXL50, TXL90, Lightning AXL50, Thunder AXL90, Sierra DXL90, Viper RXL50-70-90cc ATVs, 49cc Beamer, Matrix 50 Scooters, Polaris, Alpha Sports, Dinli, etc Sunworld H68. Original "0,2. 18-99300 - Keihin Carb Complete Jet Assortment. If the engine appears to have better power when the throttle or air valve is slightly closed, the main jet is too smell. But the chart shows one on that non-CV carb, so evidently I'm wrong. Part No 4/042-230. And you use the drill bits pins as no/go, checking them with a micrometer. I've always thought that the Air Jet is part of a CV style carb. PWK 28MM 29S #135 #38 46JJH C. The main problem with standard carbs (deploying a primary jet and a main jet) is that the main jet was required to meter fuel over too large a throttle opening. Hopefully someone out there can point me in the right direction as I've heard many answers but none the same. 0 PWK 38MM 71R #172 #58 48DEG C. 92 and the pilot jet size would be 36. size#, to the exact. It has an effect through the midrange before the jet needle takes over. When we tuned our Mikuni we tried about ten different main jets, five pilot jets and every clip position on the needle jet. Automatically and instantly get a near perfect result for the correct main and pilot jets based on your bike modifications, aftermarket exhausts, pod filters, altitude, ambient temperature etc. Mikuni Main Jets Please do a bit of homework BEFORE you call to order jets! You need to take a jet from your carb and compare it to the photos and dimensions below. It makes a difference. The following is a chart showing jet size, equivalents, and fuel flow. Cures the lean condition common when upgrading to an aftermarket air cleaner or a mild slip-on mufflers. I had measured some Mikuni main jet orfice sizes once, and got different sizes than the number (i. Avoid installing jets that are too rich as this will create a sluggish feeling at full throttle as well as contribute to plug fouling. Ralph Spencer. A main jet size of 350 would be multiplied by 0. To remedy this situation of. Note: O-Ring appears too small but it is correct, install by carefully stretching. Super A, Super B ( 1 7/8"). Mikuni Carb and STOCK Exhaust Only (look at tabs on bottom for different setup) 37 THAT MEANS NO HOUSEKEEPING, NO GOOD DEEDS, NO MERGING AND NO MESSING WITH - BY ALL MEANS ADD YOUR JETTING SPECS - THANKS!. Carburetor Assy 2. It is recomended to first change (if necessary) your needle jet on Mikuni carburetors. Set up: Needle 5EL68-3 Pilot 27. Note: Main Jets have different threads and are not all interchangeable. Reduce jet size by 2 or 2. Engine: RB22 Carb: TMX35 open mouthed Set up: 22. The jetting in your carburetor should fall within the ranges indicated within the chart. K-amp;L carries a variety of Keihin type type main jets for most popular motorcycles. Select the size which offers the best wide open throttle. 5 pilot 42-494 #152. JET SIZE MM INCHES NUMBERED DRILL BIT JET SIZE WHEN DRILLE D Cross Sectional Area mm2 #66. Mikuni "VM" Factory Carb Specs Jetting Specs ~ Carb Body Specs Throttle & Cables, Fuel Line, Reed Valves ~ ~ ~ JETTING Carb Size Main Jet Pilot Jet Needle Jet Jet Needle Air Jet Slide Cutaway 16mm #70 #25 165­O­8 3DJ3 None 2. Whatever air kit you decide to purchase or if you are jetting the carburetors because of a new. Parts Giant. 9 out of 5 stars 2 $19. What is the orfice size of these jets in thousands. Keihin to Dynojet to Mikuni carb jet conversion chart 12-28-2007, 05:26 PM I'd never seen this on Hawkgtforum and it was hard to find online, so I figured I'd post it here in case anybody gets in a pinch and wants to use other jets but doesn't know how they convert. ; Air flows faster, smoother through the TM Series venturi and jet blocks due to the flat slide design which help create a smooth bore eff. The main jet. Mikuni says that a main jet size is good for approximately a 30 degree F temp range. Thoroughly clean the inside of the float bowl prior to reinstalling it. The larger the jet number, the richer the jet. We suspected that it had been drilled out at some time, probably in an attempt to get rid of the notorious "Rochester Stumble", the result was about 8 mpg from a stock 235. 05 mm in diameter and a 120 jet has a size of 1. Add this product to my list of favorites. Pilot Jet is a 25 (I believe it could use one size smaller a 20 but I didnt order it lol) Main Jet is a 80 (Again one larger would probably work, But I didnt order it) Needle setting I had to groove needle to lean it out I believe because of the 25 pilot jet Air Screw setting here in Florida 1-1/2 turns out seems best. It is recomended to first change (if necessary) your needle jet on Mikuni carburetors. Motion Pro - Hex-Head Main Jet Tool For Mikuni Carbs. It's also Mikuni type 4/042. Clean or replace. had a “0” or blanked jet installed with a #125 main jet, you would use a #117. In addition, this tab lets to make a fine tuning adjustment to adapt to a concrete engine and. TUNING BING CARBURETORS Recommended Jetting for Rotax ® Engines This jetting chart is for sea level setting. 221-90 and get Free Shipping on Orders Over $99 at Summit Racing! Mikuni main jets are available in a wide range of sizes to accommodate your exhaust flow volume requirements. 02598" #71 66 jet. 0mm Length 5.