Intake and upgrading to 22mm carb

Discussion in 'Whizzer Motorized Bicycles' started by klinde, Oct 22, 2013.

  1. klinde

    klinde Member

    What will happen if I bore out the intake on the cylinder and the aluminum spacer to match the 22mm carb that I plan to install?

    I have gone through a lot of posts and most are about the WC1 not the NE-5. I have an NE-5.

    The following is from an earlier post.

    Hi Egor,
    The photo tells me 2 things, first it is an NE motor, and secondly the plastic spacer is broken, and you should upgrade the intake system with the Whizzer aluminum manifold kit. The manifold is standard equipment on the 2008 NE5 & Ambassador, but can be purchased [not much money, via your local Whizzer dealer]as an upgrade for the earlier models and will enhance the carburetor response. Prior to the release of the manifold kit I made and tested several versions and sizes [depth], and my tests concluded an aluminum manifold with a 18 MM hole and approx 1/2" [.545"]deep produced the most flow with the 22 MM carburetor. I think the manifold in the kit is 18MM I.D. and approx. 1" [not sure], but is a great upgrade. Don't expect the aluminum manifold to create the untimate path from the carburetor to the intake valve, because most will miss by at least 1/16", but it still works very well, and will help cool the carburetor. Here are some interesting facts, the carburetor venturi isn't 22 MM [22 MM mouth], but less than 18 MM, most of the intake port I.D.s are 18 MM, the aluminum manifold I.D. is 18 MM, the intake valve seat I.D. is 20.8 MM [valve is 24 MM]. Humm... alot of 18 MM holes in the intake system. Lets see 22 MM to 18 MM [venturi] to 18 MM [intake manifold]to 18 MM [intake port] to 20.8 MM [valve seat I.D.], makes for a nice fuel path. Don't forget to install the restrictor plate [9.5 MM I.D.] to reduce the flow [that is what a restrictor is designed to do], and you have 2 choices, either between the carburetor and the manifold or between manifold and the cylinder. Considering the carburetor lines up with the aluminum manifold nicely, I always locate the restrictor plate between the manifold & the cylinder, because the manifold port alignment I.D. is usually off a little at that junction. If the manifold alignment is off slightly then there is a minor restriction at that location, and if I locate the restrictor plate between the carburetor and manifold, then I now have 2 restrictions instead of one [one is enough for me].
    On my Ambassador motor [un restricted] I added a restrictor plate between the manifold & the cylinder and re-shaped the hole to "blend" the small difference in port I.D. alignment.
    Have fun,
    Whizzer OuterBanks LTD
    A North Carolina Corporation

    This raised another question. Sense I have already enlarged my restrictor should I get a new one and leave the inner diameter at 9.5mm?

    I measured my aluminum spacer and cylinder intake with a caliper and they are 15.5mm. The original carb is 16mm.

    My NE-5 has a sleeve in the intake port on the cylinder. It appears to reduce the size of the intake to 15.5mm. It has an outer diameter of 18mm. What happens if I bore it out to 18mm vise 22mm?

    Last edited: Oct 22, 2013