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Thread: 1972 R75/5 Carbs

  1. #1

    1972 R75/5 Carbs

    I'm working on a '72 R75/5 with the stock 32mm Bing's and I'm not seeing vacuum port take-offs like I had on my '73 R75/5.

    Just wondering if this is normal. I was hoping to do a carb synch.

    Thanks,

    RPGR90s

  2. #2
    Liaison 20774's Avatar
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    On my /7, the takeoffs are on the sides facing you as you look at the carbs. On other bikes, they're actually underneath. I would think if the carb had them, they would be the same as your other /5. But they're not standard it seems. Bing sells a kit to add takeoff ports...requires drilling into the carb body at some point.

    You can do a carb synch without the ports. Using the shorting technique will allow you to measure performance on each cylinder and make them run the same.
    Kurt -- Forum Liaison ---> 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!

  3. #3
    Quote Originally Posted by 20774 View Post
    On my /7, the takeoffs are on the sides facing you as you look at the carbs. On other bikes, they're actually underneath. I would think if the carb had them, they would be the same as your other /5. But they're not standard it seems. Bing sells a kit to add takeoff ports...requires drilling into the carb body at some point.

    You can do a carb synch without the ports. Using the shorting technique will allow you to measure performance on each cylinder and make them run the same.
    Thanks for the reply. I can synch them without the vacuum ports, just wondered if they were supposed to be there on 72's.

  4. #4
    Liaison 20774's Avatar
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    Snowbum mentions there were no take-off ports on the early /5 CV carbs. Not sure the definition of "early"...he doesn't give a date or carb number. I'm sure Bing would know. From their website: "Some early CV Carbs did not have factory VTO ports".
    Kurt -- Forum Liaison ---> 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!

  5. #5
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    Quote Originally Posted by RPGR90s View Post
    Thanks for the reply. I can synch them without the vacuum ports, just wondered if they were supposed to be there on 72's.
    I have a '72 and there are vac ports on my carbs. I also had a '72 that I bought new in the spring of '73. It was a leftover '72 at the dealer, and not a '73 model. I just blew up a picture of it, and it shows what I think is a screw where the port would be, so I believe it had ports as well. I sold that bike in '75 and got a '90S, so I never did any work on the carbs that I can remember. So I can't say for sure...it could just be a screw, or an indentation on the carb...50 year old photo, even digitally enhanced a bit still isn't 100%.

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