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  1. #1

    Join Date
    Jun 2008
    St Clair Shores, MI

    what jetting to use?

    I'm putting a 1300R motor in my 1200R. It's a 1300 power valve motor, all stock except for these cylinders It's put together with one base gasket. Ports are "cleaned up" and cylinders are decked for slightly higher compression.

    I will be using stock MY2000 1200R carbs (are they the same as the 1300 carbs?). Stock 1200 exhaust except the manifold from the 1300. Stock 1300 reeds unless someone has some aftermarket ones for sale cheap.

    I currently have the stock airbox but I will go to flame arrestors just for simplicity / cleanliness in the hull. The 1300 motor will be premix as it already has a blockoff plate and I can eliminate the plumbing while the motor is out. I'll be running premium, generally 92-93 octane.

    I want to put it together and ride. I don't want to tweak for max power, I want to be close but safe, and then just ride the piss out of it. I don't have time, don't have a tiny tach, and don't have the patience to get the last little bit out of it so I just need a good safe starting point out of the box.

    I don't want to go to a primer kit and I plan to keep the choke. I will also keep the accelerator pump unless that's considered inadvisable. I can disconnect the accelerator pump and just leave it in place as a primer (as suggested on cajundudes tech pages) if that's the best method.

    So, what jet do I use and how do I set it up?

  2. #2

    Join Date
    Jun 2008
    St Clair Shores, MI
    I've done a bunch of reading and it seems that for a 1300 with whatever porting or compression, the recommendation is 115 pilots and 135 mains. Philip_GPR says he runs 120/130 and it's fat down low, so 115/135 sounds like the ticket.

    But, it seems that everyone runs slightly different needle/seat combinations. What should I be shooting for for pop-off pressure? What about initial settings on low and high speed jets? And what about the accelerator pump... should I disable it?

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