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Old 06-26-2011, 06:30 PM   #1
iowachops
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Default Mikuni carb identification

can anyone tell me what mikuni this is? If so is there a diagram and breakdown of this online somewhere. My basket case came with two. Thanks in advance

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Old 06-26-2011, 06:35 PM   #2
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Default Re: Mikuni carb identification

that is a Mikuni VM and on the other side behind the enrichener block in real small stamping it will say some letters and numbers and some of those numbers will be 30 or 32 or 34 which is the size of the carb in millimeters.
or you could just slip it off and measure the inside diameter.
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Old 06-26-2011, 06:54 PM   #3
dan89flstc
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Default Re: Mikuni carb identification

Try Sudco, the Mikuni Distributor.

http://www.sudco.com/Carburetor01.html
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Old 06-26-2011, 07:02 PM   #4
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Default Re: Mikuni carb identification

i thought there would be some stampings somewhere but i had it all apart and there are none. on the other side it has ISO its a 34mm. Just searching Mikuni "vm" helped. I should be good from there on. Tony to the rescue again. Thanks bud!
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Old 06-26-2011, 08:07 PM   #5
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Default Re: Mikuni carb identification

Looks like a '72 T120? engine in an earlier frame from pic? Those Mikuni's will work well. I'm over in Spencer
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Old 06-26-2011, 09:32 PM   #6
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Default Re: Mikuni carb identification

They stik, its a 73 t140v in a 69 frame. We should meet up sometime.
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Old 06-26-2011, 11:05 PM   #7
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Default Re: Mikuni carb identification

the Mikuni VM's are famous for floats sticking, the floats slide up these brass pins and todays gas really gums them up.
Sudco no longer sells VM's, they have been replaced by the flat slide Mikuni's
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Old 06-28-2011, 03:21 PM   #8
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Default Re: Mikuni carb identification

Here's a post I put on another site, of a 1975 Street Chopper magazine article, on tuning instructions.
http://harleytechtalk.org/htt/index....c,28110.0.html
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Old 06-29-2011, 10:12 AM   #9
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Default Re: Mikuni carb identification

Quote:
Originally Posted by pzokes View Post
Here's a post I put on another site, of a 1975 Street Chopper magazine article, on tuning instructions.
http://harleytechtalk.org/htt/index....c,28110.0.html
Says i have to log in to see that article,anyway you could copy and paste the article here?If not ill register on that site.Thanks
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Old 06-29-2011, 06:35 PM   #10
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Default Re: Mikuni carb identification

If you would log in to Harley Tech Talk, that would be great. I have only been spending more time on this site recently, because I"m recouperating after getting out of the hospital. It's also on my "pzokes" photobucket album, along with other old tech magazines articles.

Last edited by pzokes; 06-29-2011 at 06:43 PM. Reason: more info
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Old 06-29-2011, 06:41 PM   #11
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Default Re: Mikuni carb identification

nobody runs the round slide Mikuni VM's on Harley's. that carb was really designed for 2 stroke bikes and adapted to Triumphs, many people make he mistake of running the 2 stroke needle jet and it really screws them up.
in my opinion I quit wasting time on the VM's years ago. the flat slides are ok for a Jap carb but I still just prefer to toss VM's in the trash and put Amals on it.
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Old 06-29-2011, 08:00 PM   #12
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Default Re: Mikuni carb identification

Tony,
I may be wrong, but I thought that I remembered the VM slides sticking, not the floats sticking, like you memtioned. I thought that on the early 40mm flat slides, the slides stuck too. The new flat slide carbs have rollers to keep them from from sticking. Years ago, my friends ran the early round slide VM carbs, and I'm currently running a 42mm flat slide. I do see new round slide Mikunis still being sold on Ebay. Of course that may be just old stock
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Old 06-29-2011, 08:08 PM   #13
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Default Re: Mikuni carb identification

Tony,
You probably have a lot more experience with Amals and old Mikunis on British bikes than I do. My last Amals were monoblocs on a G15. I bought a Harley after that, and never looked back,
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Old 06-29-2011, 10:56 PM   #14
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Default Re: Mikuni carb identification

The VM Mikuni is one of the best carbs ever made. Never had a slide or float stick, but if someone really over-tightened the cap it might make the slide stick, or if the carb is mounted on a big-inch HD the suction can cause the slide (any slide) to stick, that's why most HD carbs use butterfly throttles.
Both Mikuni and Amal come with either 2-stroke or 4-stroke needle/needle jet combinations. All the Amal concentrics used on Bultacos, Greeves, etc. came with 2-stroke jetting.
Anyone throwing VM Mikunis in the trash please send them to me!
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Old 06-29-2011, 11:04 PM   #15
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Default Re: Mikuni carb identification

you're right the slides used to stick wide open and made for some spirited riding. but now days it the floats that stick because of todays gas,
and I have a 40 m/m mikuni that came off a Sporty, but the round slides were never a great carb for the V twins or British twins in my opinion, they gained popularity when the variety of replacement carbs was slim. now that replacement Amal's are available there is no good reason to run Mikuni's.
although the new flats are a pretty good carb for high performance motors.

* Glider I have a box full of them I've taken off I'll gladly send them to you. and when you get a chance to do some trial and error switching try taking a well tuned British bike with a Mikuni on it and then put a new Amal on it and you will feel the increase of mid range torque, ..Now... I know all you Mikuni guys swear that can't possibly be true because a carb is a carb, and you will say it has nothing to do with torque but... it is a well know phenomenon amongst British bike restorers, I have taken off many good running Mikuni's myself and have witness this. it may have something to do with the Amal only having 2 fuel circuits. The Mikuni's do have better full throttle power but the mid range where you do most of your riding noticeably suffers, and I have done the countless hours of Mikuni needle adjustments main and intermediate jet changing,
I'm so over Mikuni's, the only people that refuse to change them out is the Norton guys, they want the simplicity of a single carb and I agree with the mounting of two Amals on Nortons it is a bit of a pain in the ass for air cleaners mounting and carb access. As for Triumphs and Bezzers throw those Jap carbs in the trash.
a great source of entertainment is forget to turn the petcocks off and put your Mikuni powered bike on the side stand and watch your whole tank of gas poor out of the any one of the thirteen overflow tubes coming out of all over on the Mikuni's.
in My opinion... Next to the JRC Keihin copy carbs, with the floats sticking the slides sticking and the loss of mid range power the Mikuni VM carbs are the worst carbs you can put on a British bike. I swap out miks for Amals all the time and the customers always say how much better the bike runs with the Amals,
and now, I apologize for this rant..I am sorry.( my hatred of Mikuni's got the better of me)
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Last edited by Tony the torch; 06-29-2011 at 11:50 PM.
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Old 06-29-2011, 11:47 PM   #16
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Default Re: Mikuni carb identification

I run a 1982 750cc left side 5 spd in a 64 trump frame. The rebuild kit for the Amal Bings was so pricey. So I bought I think 32mm Mikuni VM rounds. They were said to be set for my motor but were not. My friend re jetted on a Dyno and now they are flawless. I mean flawless. I have an urge to try a new Amal tho for low end. I can agree to older postings that VM's lack in power in the low range. But then again,, they are kind of race carbs. Deliver at mid to high end RPMs.
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Old 06-29-2011, 11:58 PM   #17
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Default Re: Mikuni carb identification

Quote:
Originally Posted by La Dolce View Post
I run a 1982 750cc left side 5 spd in a 64 trump frame. The rebuild kit for the Amal Bings was so pricey. So I bought I think 36mm Mikuni VM rounds. They were said to be set for my motor but were not. My friend re jetted on a Dyno and now they are flawless. I mean flawless. I have an urge to try a new Amal tho for low end. I can agree to older postings that VM's lack in power in the low range. But then again,, they are kind of race carbs. Deliver at mid to high end RPMs.
Try the new flat slide Mik's, they really do run great on the dyno runs we have done, but once again this is on race bikes not street bikes,
and this is also full throttle pulls, that is not how most people ride normally.
Now days Sudco no longer sells the VM's only the Flat slides.
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Old 06-30-2011, 01:43 AM   #18
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Default Re: Mikuni carb identification

^ yup, Got my round slides 2 yrs ago. Eh, so far... So good.....
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Old 06-30-2011, 08:23 AM   #19
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Default Re: Mikuni carb identification

I hope you don't mind me hijacking this thread. Just for my own curiosity, how does the Dellorto round slide compare with the Mikuni round slide, and the Amal? When you mention Amal, do you mean only concentrics, or are monoblocs included?
I have a 1938 Harley Flathead stroked to 84" that I'm assembling, and would like something reliable, but unusual. I don't have a problem making a two carb manifold.
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Old 06-30-2011, 05:43 PM   #20
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Default Re: Mikuni carb identification

Anyone have any experience with the sidedraft Weber DCOE carbs, off cars, that used to be sold as kits for Triumphs and Harleys?
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