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Thread: Mikuni TM Flatslides on a 77 R100/7

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    Mikuni TM Flatslides on a 77 R100/7

    Seems the proper jetting and details a secret on this topic? I know this is a deviant mod, but seems like there is more about how to find the right sizes for a stock motor (plug checking and stepping up jets) than other folks experiences. Has ANYONE actually put TM Mikunis on an R100/7? Rather than paying for a box of soon to be unused brass, I'd rather pay someone to just tell me the best setup for my new slides- Seeing as they did all of the work already they may as well be compensated for it.

    Thanks for any help on this guys.

    1977 R100/7
    1968 Chevy C10 (currently my towtruck)

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    Registered User RINTY's Avatar
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    Rinty

    "When you don't know where you're going, any road will get you there."

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    Welcome! You could check with Rocky Point Cycle at http://www.rockypointcycle.com/c-bmw.html and ask for their help...not sure where you're getting parts. They sell Mikunis.

    And here's a few past threads:

    http://www.bmwmoa.org/forum/showthre...uni-conversion

    http://www.bmwmoa.org/forum/showthre...-rebuild-Bings

    http://www.bmwmoa.org/forum/showthre...-Mikuni-thread

    http://www.bmwmoa.org/forum/showthre...kuni-jet-sizes
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    Quote Originally Posted by RINTY View Post
    Seems like this post indicates what came with the carb versus what is needed for operation...isn't he asking the same question as me? Happy to be corrected.

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    Quote Originally Posted by 20774 View Post
    Thanks for the direction. Got the carbs from Mikey over Martindale Motorworks (great guy and shop). Seems these threads have some general like and dislike info, but no specific jetting/needle details. Been in and out of all the mikuni threads on MOA, just not finding it, hence the request for someone to impart their wisdom from experience.

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    Administrator 20774's Avatar
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    Here's something on the basics for tuning Mikunis...not the experience you're looking for, though.

    http://www.iwt.com.au/mikunicarb.htm
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    Registered User RINTY's Avatar
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    Quote Originally Posted by Dhkreitz View Post
    Seems like this post indicates what came with the carb versus what is needed for operation...isn't he asking the same question as me? Happy to be corrected.
    Re-reading his post more carefully, I think that may be the case.
    Rinty

    "When you don't know where you're going, any road will get you there."

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    I would find some place to "start" then figure it out yourself.

    What I have seen done, is to run the bike at a certain speed (let's say 1,000 for idle long enough to let mixture affect plugs. Then without changing RPM's at all, shut off electrics to kill engine. Then check plugs. See color. If too lean, replace/adjust jetting for that particular RPM range. Then do at a different range, like 3,000 RPM. Key is to run long enough to affect plug coloration, AND shut off engine electrically so that it does not run on its own at any other range. Check plugs for color - then, change/adjust jetting for THAT range. And keep doing until plugs show an acceptable color (light tan) for all ranges.

    Remember, a jet can be drilled larger to get more fuel (carefully).

    This all has to be repeated several times as jetting at one range does partially affect jetting in other range(s).

    See if you can get a "selection" of jetting from a dealer who will let you return the ones you don't use, and pay for the ones you do!
    "The difference between death and taxes is that death doesn't change every time congress meets." - Will Rogers

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    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    AFR monitoring

    Quote Originally Posted by Dhkreitz View Post
    Seems the proper jetting and details a secret on this topic? I know this is a deviant mod, but seems like there is more about how to find the right sizes for a stock motor (plug checking and stepping up jets) than other folks experiences. Has ANYONE actually put TM Mikunis on an R100/7? Rather than paying for a box of soon to be unused brass, I'd rather pay someone to just tell me the best setup for my new slides- Seeing as they did all of the work already they may as well be compensated for it.

    Thanks for any help on this guys.

    1977 R100/7
    1968 Chevy C10 (currently my towtruck)
    Seeing as how you have engaged in what you describe as a "deviant mod" lol, you might not be adverse to taking the reigns and measuring directly the afr's that are developing as you ride and your Mikunis are performing. Adding a wide band sensor/ gauge allows immediate read on the behaviour of the entire system, and each bike/ motor tends to have its own quirks and ultimate reaction to say one given jet size. Although this is a rather simple install on most bikes, it does involve some rudimentary wiring, and the addition of a sensor bung to the exhaust work which may/ may not draw approval depending on a persons particular level of "deviancy". However, there is no more accurate way to see the full picture and take a stab at gaining results that actually deliver your desired operation.
    I utilized an Inovate WB system on my bike prior to the more aggressive modifications, and was impressed and shocked at the behaviour & readings of the original stock Bings. Apart from rather dark reading plugs and tail pipes that always seemed to have higher soot content than normal, the bike ran very nicely and I would have been hard pressed to change things. In fact accel was going horribly lean, and cruise went significantly rich (can provide some numbers although mute point as you're seeking Mikunis data).
    I can provide some recomendations on affordable and robust WB kits if you wish, otherwise good luck on your procedures and outworking.
    Lorne.
    Last edited by R100RTurbo; 05-04-2014 at 03:05 PM.

  11. #11
    Registered User RINTY's Avatar
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    Sudco sells a Mikuni tuning manual for $14:

    http://www.sudco.com/Books.html
    Rinty

    "When you don't know where you're going, any road will get you there."

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    I've always wondered why aftermarket carbs are better than the Bings. I liked the accelerator pumps on the Dellortos, but the Mikunis don't have that, right?

  13. #13
    Registered User RINTY's Avatar
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    Quote Originally Posted by 44817 View Post
    I've always wondered why aftermarket carbs are better than the Bings. I liked the accelerator pumps on the Dellortos, but the Mikunis don't have that, right?
    Some of them do, and some of them don't.
    Last edited by RINTY; 05-05-2014 at 02:19 PM.
    Rinty

    "When you don't know where you're going, any road will get you there."

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