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techtalk:ref:carb01g [2019/09/08 21:25] (current)
hippysmack created
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 +====== REF: Carburetor, Intake Manifold & Exhaust - Sub-01G ======
 +\\
 +====== Basic Mikuni VM Information ======
 +===== VM Series =====
 +
 +These are early VM series round slide Mikunis - 34mm, 36mm, or 38mm \\
 +Only Mikuni round slide carbs are designated as VM. These are available in different sizes such as VM29, VM34, VM38, VM40 etc. ((piniongear of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1675923&​page=2)) \\
 +HS and HSR carbs are not round slide. The RS is not a round slide. The TM and TMS/TMX are not a round slide. \\
 +This is a very old school set up for a Sportster. Properly set up, this carb gets good mileage and runs well. ((nemosengineer@yahoo.com of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=266722)) \\
 +**Note Safety Tip**: Cut a piece of bicycle inner tube to stretch over the carb-body and slide-cap to stop the cap from un-screwing. \\
 +This will keep the slide and needle inside the carb on the freeway. \\
 +You can call Sudco to see what they recommend for jetting after you identify which model Mikuni VM you have. \\
 +Sudco will get you close. You can also get a little tool kit they sell with the jet wrench'​s and don't forget the Mikuni pocket tuner. \\
 +
 +Mikuni lists the following Vintage Carb Kits: ((piniongear of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=765846&​page=8)) \\
 +001-200....HDS-101/​38mm.... Sportster/​Shovelhead \\
 +001-204....HDS-101A/​40mm.... Sportster/​Shovelhead \\
 +001-202....HDS-101B/​44mm.... Sportster/​Shovelhead \\
 +So any of these 3 sizes will work.
 +
 +**Considerations When Buying**: \\
 +The Mikuni will stick out a bit further than other carbs, mainly because of the adapter. \\
 +On a Sportster, you need to buy a throttle cable with the carb that has a 90° elbow fitting into the carb top. \\
 +This is needed to be able to run the throttle cable under the gas tank. \\
 +A new manifold is required along with a carb adapter or rubber boot and air cleaner mount. \\
 +Several ways are described in the mounting article above. \\
 +
 +
 +The correct version of the VM38 for an ironhead Sportster is the VM38-9. ((IronMick of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1814834&​page=2)) ((piniongear of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=765846&​page=3)) ((piniongear of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=765846&​page=4)) \\
 +The VM38-"​9"​ was setup and extensively tested by Jerry Branch for the stock Sportster engine using flow bench tech for the time. ((simeli of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1636803&​page=2)) \\
 +It is going to be hard to find that you are going to be able to improve on it as supplied. Unless you are running a stroker or highly modified heads and cams. \\
 +Then the as supplied needles and jets are going to be your best option. Clean it out and replace with the normal "​9"​ needles and jets. \\
 +
 +There were a bunch of different VM's (round slide) from 16MM on up to 44MM with the vast majority of them designed for 2 cycle engines. \\
 +The VM-38 Standard Right body may be the same for all of the 38MM units. \\
 +However, all the particulars have to be correct for the VM38-9. Below is the list of all the things that make it a "​9"​. ((simeli of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1675923)) \\
 +  * Bore Size : 38mm
 +  * Spigot Mount : 43mm
 +  * Main Jet : 4/042 #330
 +  * Pilot Jet : VM22/210 #30
 +  * Needle Jet : #166 Q-2
 +  * Throttle Valve : VM38/24 2.5
 +  * Jet Needle : 6DP1 (the clip is set in the middle notch. That is the third notch from the top or bottom.)
 +  * Needle Valve VM34/39 3.3
 +  * Air Jet : 2.0 for Sportster (002-165) \\ 0.5 (BS30/97) for BTs but reportedly works fine on a Sportster. \\ Sudco'​s website shows a 0.5 for the VM38-9 but the VM-38 manual says the 2.0
 +
 +This particular model is a VM-38mm. It has no numbers on it other than "​Mikuni KOGYO"​. \\
 +{{:​techtalk:​ref:​carb:​38mm_mikuni_vm_pic_1_by_sturgmachinist.jpg?​direct&​300|}} ((photo by sturgmachinist of the XLFORUM http://​xlforum.net/​forums/​showpost.php?​p=1361935&​postcount=1)) {{:​techtalk:​ref:​carb:​38mm_mikuni_vm_pic_2_by_sturgmachinist.jpg?​direct&​300|}} ((photo by sturgmachinist of the XLFORUM http://​xlforum.net/​forums/​showpost.php?​p=1361935&​postcount=1)) \\
 +
 +Here is another VM-38. \\
 +{{:​techtalk:​ref:​carb:​vm-38_pic_1_by_donw.jpg?​direct&​300|}} ((photo by DonW of the XLFORUM http://​xlforum.net/​forums/​showpost.php?​p=3984744&​postcount=1)) {{:​techtalk:​ref:​carb:​vm-38_pic_2_by_donw.jpg?​direct&​300|}} ((photo by DonW of the XLFORUM http://​xlforum.net/​forums/​showpost.php?​p=3984744&​postcount=1)) \\
 +
 +Mikuni VM-38 with solid mount adapter to run on a shovelhead. \\
 +The adapter is a tight press fit with three set screws. There are threads in the adapter to run the bolts into. \\
 +And there is a groove /O-ring inside the aluminum adapter bore. \\
 +{{:​techtalk:​ref:​carb:​vm-38_pic_1_by_claysbury.jpg?​direct&​300|}} ((photo by claysbury of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1814834)) {{:​techtalk:​ref:​carb:​vm-38_pic_2_by_claysbury.jpg?​direct&​300|}} ((photo by claysbury of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1814834)) {{:​techtalk:​ref:​carb:​vm-38_pic_3_by_claysbury.jpg?​direct&​300|}} ((photo by claysbury of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1814834)) \\
 +
 +This one is stamped "​X66"​ with the X above the 66 and one of the 6's is sideways. It also has 38F 9 on the back side just below the choke\enricher. \\
 +{{:​techtalk:​ref:​carb:​vm-38_pic_1_by_asasial.jpg?​direct&​300|}} ((photo by asasial of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1151844)) {{:​techtalk:​ref:​carb:​vm-38_pic_2_by_asasial.jpg?​direct&​300|}} ((photo by asasial of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1151844)) \\
 +
 +{{:​techtalk:​ref:​carb:​vm-38_pic_3_by_asasial.jpg?​direct&​300|}} ((photo by asasial of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1151844)) {{:​techtalk:​ref:​carb:​vm-38_pic_4_by_asasial.jpg?​direct&​300|}} ((photo by asasial of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1151844)) {{:​techtalk:​ref:​carb:​vm-38_pic_5_by_asasial.jpg?​direct&​300|}} ((photo by asasial of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1151844)) \\
 +
 +**Fake vs Genuine Mikuni VM**: \\
 +The fake VM carburetor has the "​Minkui"​ imprinted on the top and side of the carburetor. \\
 +On a genuine carburetor you will find the "​Mikuni"​ logo. \\
 +Also you will notice that the fake carburetor doesn'​t have the "NOT FOR AIRCRAFT USE" decal and the anchor plates. \\
 +The way the fake carburetor was designed is completely different from the genuine one. There are extra openings and attachments. \\
 +Also see this [[http://​www.sudco.com/​genuine_vs_fake_carburetors.html|Sudco International]] web page for pics of fake vs genuine VM carburetors. \\
 +
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