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  1. #1
    CB750 New Member Nbates's Avatar
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    New member- Carb work 1981 cb750 dohc Cafe racer

    Hey all new member here. Not too long ago I bought a cb750 that had already been converted to a cafe racer. It currently has pods and a 4into1 exhaust straight piped. It was running good for awhile but quickly notices it was running pretty rich and has trouble cold starting when the temp is low. I am going to do the carb rebuild. Any advice on the tune with this setup or anything else I should look out for would be greatly appreciated. Thanks in advance!

    Sorry meant to post in carb section and now cant figure out how to delete and repost. If you couldnt tell I was a noob before
    Last edited by Nbates; 02-09-2021 at 06:13 PM.

  2. #2
    CB750 Guru amc49's Avatar
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    They go rich with the pods, it causes them to open slides slower and later making engine richer. Then people think you have to 'jet up' for the pods making it even worse.

    If your plugs are black or dark the engine will tend to not light off cold as fast.

    It's the CV carbs, they do not work like direct lift ones at all with pods.

  3. #3
    CB750 New Member Nbates's Avatar
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    Amc49 thank you! Yes after reading previous posts I saw how much of an issue the pods can cause. And I am not opposed to returning it to the stock airbox which I did get when I got the bike. To your knowledge if I return to stock airbox will there be any particular tuning issues with the exhaust set up? Thanks again!

  4. #4
    CB750 Guru amc49's Avatar
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    Should work fine if you jet up the main jet only maybe by 10 higher than OEM, provided the header is one that 'works'. Use the OEM paper or whatever filter comes in the box, they can even be sensitive to that, the 1st gen DOHC is for sure, a K&N put in airbox lowers performance even there, they again flow too easy.

    The carbs work best when there is slight restriction in the box, it lowers pressure to allow the carbs to open slides more. Why pods mess things up, they allow the entry pressure to be at full atmospheric, the CVs want a slight vacuum and even more at wide open throittle, it is what allows the slides to 100% open at WFO.

    Direct lift carbs open the throttle by cable and love low resistance to increase power, the CVS are the opposite to a degree. You have to trick the slides into opening before you can even think about high performance.

    Probably wouldn't hurt to check engine compression, the slides lift based on that too, they need good engine vacuum, it drops instantly when compression lowers.

  5. #5
    CB750 New Member Nbates's Avatar
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    amc49 once again thank you. I plan to get started in the next couple weeks if randaaks get the kits back in stock otherwise I will have to try to source another. Any knowledge of this motorgenics site? seems too good to be true. Thanks!

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