Whizzer Custom Long Intakes

[Tony01]

Custom made mild steel long intakes for WHIZZER motorbikes.

21.5mm inside diameter, 48mm bolt spacing, 1/4” thick flanges, 2mm tube wall thickness. Inside welded.

i have 3.3” and 2.8” lengths. I can pretty them up like that one that I made for a guy, I’ll find the pic later

$40 shipped each

 

[Tony01]

Ok so I made 3 and sold one, also sold flanges and tubing to a couple of people.

I measured up an NE-5 intake port and drew up a flange. The ports are .020” off center left to right so I made the flanges .010” off and was careful to make sure they were welded in the right direction. The port is also off from the line between the flange bolt holes and it is all correct. The step file is buried in my computer.

The flanges were lasered with big hole at .998” and chamfered significantly, a 1” ERW tube was then press fit and welded into the back chamfer.

I did these before I had a belt sander, so it took me a long time to sand them by hand on a piece of granite and I didn’t fill pinholes like I wanted. I can build them up and sand them down in minutes now if needed (it took me 4 hours of sanding like this to shave a 212 head .067” once).

I like my intake manifolds clearcoated. The only clear I have found that doesn’t allow the metal to rust is clear exhaust paint that I have to bake in the oven. It leaves
a pleasant amber shade.

 

[wrench]

Intake manifolds look good for a 212cc , but not good for a Whizzer

Whizzer Vintage cyl intake manifold extends

Whizzer 1999 - 2004 WC-1 Cyl intake manifold extends

Whizzer 2005 - 2009 NE-5, NER, Ambassador Cyl uses a 1" intake spacer

A longer throttle cable will be needed and all the Whizzer guys I know with the NE-5 use an intake spacer 1" or shorter for best performance

 

[Tony01]

Whizzer 2005 - 2009 NE-5, NER, Ambassador Cyl uses a 1" intake spacer

A longer throttle cable will be needed and all the Whizzer guys I know with the NE-5 use an intake spacer 1" or shorter for best performance

These are NE-5 parts. If the carb was right on the motor, it could interfere with the cylinder with its bowl due to the downward angle of the port.

Best performance for a flathead is the highest torque, which is not going to happen with a 1” intake. A longer intake will increase torque.

Flatheads have inherently bad flow. The guy I made this for had the 1” spacer and a 22mm carb which was too big for his 148cc so his intake velocity was even lower. A well setup carb is supposed to be ice cold during normal operation, instead his was BOILING the fuel in the carb because the carb wasn’t seeing enough vacuum.

My 148cc Briggs flathead was WAY faster; not even being a specially designed motorbike engine… just by having a properly setup engine intake and exhaust. I had a 16mm carb with a 3” intake and my carb was always ice cold.

Also that 1” spacer had a HUGE 1” thru hole so you can kiss port matching goodbye.