Mikuni BS32 rebuild with a few questions please

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29 Jun 2021 16:43 - 29 Jun 2021 16:46 #850918 by Ninja1195
I am in the process of rebuilding the Mikuni BS32 carbs that came stock on my '82 CSR650.

I disassembled the carbs and ran them through my ebay ultrasonic cleaner with w touch of Dawn dish soap. Came out nice and clean and now time for the assembly.

Ordered a quality rebuild kit from ebay as per the suggestions on this forum. Now for the questions.

I have a few "left over" parts after my rebuild as seen in the first picture. Any suggestions?

Also my carbs are missing one of the plugs as seen in the last picture. Are they generic to Mikuni? I assume they MUST be installed? Suggestions as to where I might purchase them?

My carbs have slightly different brackets under the float bowls that another set of Mikuni (picked up some cheap spares to learn on) does not?

Thanks

1978 KZ650 B2
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Last edit: 29 Jun 2021 16:46 by Ninja1195.

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29 Jun 2021 18:12 #850930 by Nessism
I've never seen the carb plugs sold anywhere.  You may need to purchase a spare carb body and cut it open to harvest the plug.

Those aluminum disc things are intended to seal over the pilot screw passage.  Throw them in the trash.  They are not needed.
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30 Jun 2021 12:01 - 30 Jun 2021 12:04 #850966 by ghostdive
Replied by ghostdive on topic Mikuni BS32 rebuild with a few questions please
If you ride in the rain and haven't tossed those aluminum plugs, I'd have to disagree with Ness and say that you should pop them in once you have your bike running and the pilot screws adjusted right - I ran without pilot screw plugs for a while and water regularly got into #1 and #4. If you garage your bike and only ride on nice days it's not an issue. EDIT: I also dropped a touch of superglue around the edges of the plugs, since they didn't fit snugly.

As for the pilot jet plug that you're missing, try this:

www.partzilla.com/product/kawasaki/92066-1087

You'll need an o-ring for it as well.

1982 KZ750 Spectre - 6 speed swap, BS34s, 18" rear wheel

2001 ZX-6R
Last edit: 30 Jun 2021 12:04 by ghostdive.

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30 Jun 2021 16:05 #850978 by Nessism
It's not the pilot plug that he needs, it the tapered aluminum plug that's a press fit into the carb body.

Installing the aluminum disc over the pilot screws isn't the worst thing in the world, but if protection from the elements is a concern, I'd rather fill the cavity above the screw with something like waterproof grease.

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01 Jul 2021 00:17 #850996 by gazzz

Installing the aluminum disc over the pilot screws isn't the worst thing in the world, but if protection from the elements is a concern, I'd rather fill the cavity above the screw with something like waterproof grease.


Mikuni that was installed on Yamahas came with rubber plugs for pilot screws. Part number is 22F-14991-00-00. Still could be sourced.

Kawasaki KZ650 cafe-racer: in progress

Kawasaki Zephyr 750 (810ccm, 4in4, spoked wheels)
Honda CB815 "Eight Fifteen" cafe-racer
Yamaha XJ "Eight Ball" cafe-racer

www.gazzz-garage.com
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01 Jul 2021 01:59 #850999 by Ninja1195
Replied by Ninja1195 on topic Mikuni BS32 rebuild with a few questions please
Thank you all.

What about those springs that seem to be left over? Any thoughts?

1978 KZ650 B2

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06 Jul 2021 14:12 #851402 by Ninja1195
Replied by Ninja1195 on topic Mikuni BS32 rebuild with a few questions please
No eBay APP ID and/or Cert ID defined in Kunena configuration

Well these arrived today and they are indeed a nice snug fit !

1978 KZ650 B2
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25 Apr 2022 18:12 - 27 Apr 2022 07:12 #866160 by valyx
Hi to all. I think this is my first post/comment on this forum.
I have a few questions for BS32 as well... I got them in parts.

1) jet needle setting (4d31) how many "clips" from top? I attached a picture.
2) where to measure float height from the float? i am following this tutorial since it is my only lead (cant find a manual - 1982 z650f3) thexscafedotcom.files.wordpress.com/2014...rebuild_tutorial.pdf
I need someone to confirm the measurement is correct. For now, the height (22,4give or take 1mm) is set on top of the float (in the attached picture B option).


 
  • Last edit: 27 Apr 2022 07:12 by Street Fighter LTD.

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    26 Apr 2022 16:31 #866199 by Nessism

    Hi to all. I think this is my first post/comment on this forum.
    I have a few questions for BS32 as well... I got them in parts.

    1) jet needle setting (4d31) how many "clips" from top? I attached a picture.
    2) where to measure float height from the float? i am following this tutorial since it is my only lead (cant find a manual - 1982 z650f3) thexscafedotcom.files.wordpress.com/2014...rebuild_tutorial.pdf
    I need someone to confirm the measurement is correct. For now, the height (22,4give or take 1mm) is set on top of the float (in the attached picture B option).



     

    Are those the stock needles, or some aftermarket needles from some "carb kits?"  Stock Mikuni is generally preferable.  If forced to use the aftermarket needles, put the clip is the middle position and adjust for best running.  And realize, the carbs are set up for using the airbox, not pods.

    The tutorial highlights the correct measurement location.  Float height isn't critical though, fuel level is.  Measure the fuel level to 4mm below the edge of the float bowl.

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    27 Apr 2022 03:23 #866211 by valyx
    I hope needles are stock, someone probably had some problems with the bike running, because i have carbs from gpz750a1 (black ones). If I will notice rough running i will put the clip in middle position. I have airbox, dont wanna mess with pods with CV carbs anyway.

    I will adjust the float level.

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    12 May 2022 01:03 - 12 May 2022 01:21 #866958 by valyx
    Adjusted floats now they are 4mm below edge... new air filter, b8es spark plugs, valves were adjusted, carbs cleaned, jet needle clip is in the middle position. pilot mixture screw is 2 turns out. carbs are bs32

    now the problem is spark plugs are lean to my knowledge. Cold start is difficult, because it runs on middle 2 cylinders, but it gets better if i put my hand over airbox intake (lean again?)

    in need of a third opinion here.
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    Last edit: 12 May 2022 01:21 by valyx.

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