Athena 70 kit

[dandanman232]

Hey guys I’m finally gonna Finnish my bike. I decided I wasn’t going to use the stroker so I need to know what’s the best intake and carburetor to go with my Athena 70 race kit and my polini race 4 exhaust? I don’t know to go with the polini 19 or 21 and not sure if the 32 mm mvt sc intake that I want please help so I can Finnish this

[dandanman232]

? Come on guys please so I can post soMe pics and rip

[90GTVert]

19-21mm are both likely to work well. ScooterTuning sells a package with the kit and pipe that includes a DellOrto PHBG 19, so that's likely to be a good choice. You should be able to use the PHBG 21 as well and get great results with a little more headroom. I'd expect the Polini CP carbs to work well in both sizes too.

I've never used a CP. I've used PHBG 19 and 21mm carbs with stock intakes many times. Some stock intakes are a little small, but can usually be modified. You can also get a little larger version of a stock intake (21mm) for $10-15. With a stock (ported) intake and Dell 19-21mm, I use the stock airbox and usually remove the snorkel. A larger snorkel may be even better, but that has worked fine for me for many setups and it's pretty quiet and not so responsive to weather like a pod filter.

www.scootertuning.ca/en/46-intakes

[ThaiGyro]

My experiences are more race bikes than street...so everything that Brent stated works. My OEM sort of stock Honda Gyro ran best with a 17.5 carb...but with a bit-of-pipe and good ignition that little 50 could run a 19 at varied altitudes with little fuss.

That meaning...I will always run a slight bigger carb over a smaller, if ideal one. I think this way: Jets are controlling fuel transitions mostly... More air is always easier to tune with than borderline to not enough.

My old mentor would say, [Think of carb tuning as painting a car. Your spray is in a three foot arc, but your target is flat. As you make a pass, the middle section will have better coverage than the extremes.] In scooter tuning that middle is your overall range...but you must fine tune the top and bottom.

Air flow is not flat. Go big and tune to great...or start small and reach a limit? Either can work. It is just money. It is your future goals/budget that should matter most.

[Lucass2T]

I run a 19mm phbg on my Suzuki TS50W. It's a 50cc geared bike (no variator, but should make no difference).
It comes stock with a 18mm mikuni VM which is prettig big for a stock 50cc streetbike.
It runs great, and has pretty decent pickup and throttle response for what it is.

From what i've read and seen through the years on other ppl's setups, 19-21mm should support every 70cc. From a stock cast iron 70cc up until a full race polini cup bike (the latter are restricted to 19mm).