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Thread: Mikuni Carbs

  1. #1
    wbiery
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    Mikuni Carbs

    Has any one run them? I'm just curious. What say you.

  2. #2
    I asked a similar question not too long ago and got blank stares

  3. #3
    VANZEN
    Guest

    blasphemy !

    Mikunis on a BMW ? That's blasphemy ... what would Max Friz think ?

    (couldn't even say that with a straight face)
    Mikuni VM and TM type carbs are a significantly popular choice as an aftermarket replacement,
    and VM Mikuni is THE choice for those that run AHRMA Vintage BMWs ...
    which is a clue that the Mikunis work best as "performance" carbs.

    One might easily take the position that the Bing Constant Depression carb as fitted by the factory to a stock engine
    is a better "all around road and touring" choice and well suited to the Type-247.
    The CD carb being less affected by elevation changes than the slide carbs. Easier to 'dial in' without nagging flat spots.
    Requiring less finesse with the throttle ... if quite "sluggish" in comparison to a well tuned slide.

    Personally, I have not run Mikunis on a BMW (being the stuffy traditional type that I am and preferring D'ellortos),
    but have used them on other marques and found them to be quite satisfactory.
    I suspect others here who do have them on their BMWs will chime in with their experiences.
    If responses should be lacking on this site, try BOXERWORKS – those old hooligans have tried all that crazy stuff.

    The place to buy Mikuni VM kits for the Type-247 would be ROCKY POINT CYCLE
    They sell complete kits for the Type-247, are good about helping with tuning info, fitment, and such,
    or SUDCO which sells VM and TM carbs and kits – if you should decide to go that route.
    Last edited by vanzen; 12-07-2008 at 06:03 PM. Reason: proper carb I.D.

  4. #4
    Registered User Rinty's Avatar
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    Hi Jinx: (no pun intended)

    This is a not uncommon mod for airheads. Just do an advanced search under Mikuni in the airhead section, and you'll pull up some threads.

    You're supposed to get better throttle response with them, and they look very cool. Another theoretical advantage is the mechanical accelerator pump, which should make for easier cold starting, in that you can squirt fuel into the cylinders, but my tech says this is not the case.
    Rinty

  5. #5
    Nutfarm
    Join Date
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    I put a set of 32mm Delorto carbs on a R75/6, they work quite well. I also have a Norton 850 that I installed a single 34mm Mikuni on and it also works quite well.
    The British group feel the same about Japaneese parts on the bikes, but it always starts hot or cold idles evenly and comnonly gets 60 mpg. Not so with the Amals. So if you are a purest or put your bike in the shows you have to have the OE carbs. But if you want to ride, and you have an old worn out pair of Bings by the time you have them rebuilt, or buy the parts to do it right you can by a pair of new Mikunis, You'll take some heat from the it's got to be German group, but your bike will run well. Alittle tuning is required but once done they are set and forget carbs.

    Ken G.

  6. #6
    VANZEN
    Guest

    pump

    Quote Originally Posted by rinty View Post
    ... Another theoretical advantage is the mechanical accelerator pump, which should make for easier cold starting, in that you can squirt fuel into the cylinders, but my tech says this is not the case.
    Quite theoretical – as neither the VM (round slide) nor the TM (flat slide) Mikuni has an accelerator pump.
    A popular Mikuni model that does have a pump, the RS (radial slide), is rarely seen on a BMW.

    Dellorto PHM models, used as factory equipment on the R90S,
    and also a popular aftermarket choice DOES have a pump.
    (performance tuners will often disable it's action)
    Last edited by vanzen; 12-07-2008 at 05:57 PM.

  7. #7
    wbiery
    Guest

    Mikuni Carbs

    Thanks all for your input. I will be attending the Super Tech session and will ask questions there. The rocky point ad is what made me start to think about it. thanks for not giving me that old saw about "where would I get parts if I was out on the road." It is getting very hard to find a dealer. I know I know I should just be glad I can get parts in 3 or 4 days. I doubt the Mikuni's would ever need parts. I would like to " keep things German."
    By the way does anyone know where I can get Bosch plug wires? I have to say it's great being part of this family, Thanks.


    Jinx:

  8. #8
    VANZEN
    Guest

    wired

    your wire needs will depend on year ΤΗτ
    or more precisely, whether points or electronic.

    a good source for parts on line is MAX BMW

    they will have the OEM parts

    I would use NGK ... buy by the foot, and build my own.

  9. #9
    Nutfarm
    Join Date
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    Folsom CA.
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    PT9677, I agree that new concentrics, or ones that have been sleeved, or better yet the MKII's work well if tuned correctly. I have never seen 90 mpg, but I have seen 75 mpg on a BSA I have with a concentric in good condition. The point here is why mess with a old carburettor, parts are expencive, (check the price of a slide for a Amal) and Bing parts are no better, If it's a diecent running motorcycle you're after, it's hard to beat a Mikuni for the money. I have installed Delortos, the newer Amal MKII's, Kehin, and Mikuni carburettors on verious motorcycles over the years, they all work well if in good condition.

    Ken G.

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