Mukini TM Flatside - No reed valve 2 Strokes

[BEN173]

Anybody like to comment please. I was considering using a TM28 on a no reed valve VMX Two Stroke.

JETTING THE 28mm MIKUNI ON PISTON PORTED ENGINES (NO REED VALVE)

It is very important on piston ported cylinders with the TM28 carb that the proper atomizer is being used. It should be of the 169 series (usually 169-P0), and the shield at the top should be trimmed down to 3 to 4mm (the lower it is trimmed the leaner your carburation will be in the 1/4 throttle range). These carbs come stock with a 175 series atomizer, which is only suitable for reed valve engines such those fitted with Imola or TS1 cylinder kits. We always supply the 169 series atomizer with the carb kit when we sell it for piston port use. It is also often necessary to raise the cutaway on the front side of the slide to about 4mm to clean up the jetting in the 1/4 throttle range. This can be done with a rotary flap wheel on a die grinder, being careful to mimick the arc of the original cutaway.

http://www.lambretta.net/lambretta-tech-center.htm#jet28

[Hoony]

this carb will not be legal for pre 75 class if you compete, assuming that is what you are going to use it on.

[David Lahey]

It is normal for reed valve motors to require different jetting to piston port motors of the same capacity even with round slide carbies, due to the reverse flow effect in the piston port motor.
It should be no surprise that a TM Mikuni needs to be set up differently for a piston port motor