Got it going! 70CC and Variator!

[burnt_toast]

get a unifilter. supposed to work better and easier/cheaper to clean.

http://www.unifilter.com/

[the496rocket]

Yeah, The guy I got my kit from has the uni filter I can buy from him, looks a little bigger than the k&n which is what I want, although I cant find the right size on the uni site. Does anyone know the uni part # so I can see if I can get locally? or any other brands? (so far UNI looks the best)

[burnt_toast]

well the one i got is 14-0401, 1.5" x 4" dimensions.

however its for my vento carb, and I don't know if urs is 1.5"

let us know what size inlet ur carb has.

[vette76]

1 1/4 i believe

[the496rocket]

I am wondering, I've read that sprees or aeros need the air box and filter to create a restriction for vacuum, If I get a different air filter, will I have issues with vacuum to operate the fuel valve and oil?

Does the engine vacuum help draw the oil from the pump into the intake?

[maddog]

oil pump works off the crank gear, fuel valve works off intake vaccuum.

[maddog]

vt cycles gas a cht gauge and hi-speed cooling fans, keep the fan shroud on you can also use header wrap tape on the exhaust to keep heat away from engine, you can use the stock airbox just open up plugged side on the air intake.

[noiseguy]

I am wondering, I've read that sprees or aeros need the air box and filter to create a restriction for vacuum, If I get a different air filter, will I have issues with vacuum to operate the fuel valve and oil?

Does the engine vacuum help draw the oil from the pump into the intake?

The restriction is at the carb, and the engine will always draw vacuum when it runs. It has to to get fuel!

One of these days I'm going to write an article on this whole airbox thing to describe the actual physical principles involved. But for now:

The pod filter will screw up running unless you change the jetting. It effectively shortens the length of the manifold tract, and takes out the volume of the airbox. This makes it ram air better at high RPM and poorly at low RPM. The tube/airbox setup works better at a variety of RPMs. I think the real reason that you need a bigger jet with the pods is that the carb is using the air/fuel mix really inefficiently.

If you are racing a 2-stroke, you can build a 15 HP 50cc 2-stroke that will run like a scalded dog between 11K - 13K RPM or so. It will make really crappy power at lower RPMs though, so it's not really "streetable." Besides that it would need rings every 100 miles or so, and be constantly overheating around town. When racing, care is taken so that the gearing can keep the engine in that range. Scooters can't play with the gearing, although the variator can keep it within a tighter range than a Spree, which runs 1 ratio.

My thought was to tune the pipe-intake on the Spree to make good power around the 8K - 10K range, and then bump the clutch springs up so that the clutch engages around 5K RPM, rather than 2-3K like it does now. Then you should get an acceptable launch, although you'll wear out clutch shoes faster. You could tune the intake length shorter to help the engine in this range; it would be about 1/2 the length of the current system, by my numbers. Might still not work as well as stock, though.

I've had poor luck getting my Spree to work with a pod. A #80 jet was almost large enough. But I thought that's a ridiculous size to have to use on a stock engine, so I stopped bumping up jets and started reading about intake runners. That's how I arrived at the above.

[the496rocket]

Ok, the reason I was wondering about a cone filter because I have the 70cc, and intake/ports opened, and #95 jet, I had the stock airbox on, and it ran fairly rich, but with the box off, or lid off, it runs lean. throttle valve is on top leanest notch, so what do you suggest for air intake?

[noiseguy]

Either run the smaller jet with the airbox, or get a pod filter and rejet to get your heatrange right. Running with no filter is different than running with a pod.