MOPED ARMY

You can really fuck up a good cylinder with a bad port job. Don't just start hacking away at the ports without any idea as to what you are trying to do. Get the timings on the ports, run some math, read up on all the two stroke tuners books you can find and figure out the best port timings for your pipe of choice. Make some aluminum spacer gaskets to raise the transfer ports to the specific transfer duration you calculated and make sure all the numbers work together (i.e. time it with a measurement wheel attached to the crankshaft) and then fucking rip.

i have modified the piston... they have different pistons... so if you dont have windows on top, or have 4 holes, make them into 2 squares matching the transfers on the top of the cylinder.

also, i was looking at mine yesterday, and i was thinking about opening the side ports a little on their bottom, and taking a bit off the sleeve of the cylinder too to match the inside of the ports

...if that makes sense.?

hmmm... the transfers above the intake are timed differently than the regular transfers. I think that you should make all the transfers open at the same time if you can get the dremel in there, or you could just dremel the top of the piston. Make the portmap look like this:

Yeah I'm not messing with the loop scavenging bit. That map looks pretty sweet, though; I'll probly give it a whirl.

thats a pretty extreme port map. they have bad enough low end as it is. I've never ported one myself, but if I were, i'd do the exhaust in stages. I think its too big as it is for daily driving.

That port map is pretty much stock except for the exhaust port is more wide and maybe 1mm higher

or try this:

take about 3 mm up on the intake side of the piston and make the holes into squares port the rest to the extreme shown.

made a k star rip but lost low end, use in conjunction with a well tuned 19phbg, and decent pipe that shitty kit will hit really high rpms

don't think too much, less math and more experimental cylinders will make ur port work better and u'll have more fun. just look at a puch low torque cylinder there arn't even port walls, try that on a kit i bet it rips.

also polish up the exhaust.

Never worry about low-end when porting, unless you want to ride with a stock clutch.New top-end power is always taken out of the low-end power.

The portmap that Eric posted is very conservative compared to my portmap. Elliot's portmap looks a lot like mine, altho I didn't raise the intake like he did, I just widened it and shortened the piston.

My TCCD gets a good 45MPH, but that's because I gear low. I'm not a top-speed guy, I am however a high-rev cylinder guy. My kit screams (11.5k RPM) and absolutely rips with both a Proma Circuit and a Proma LowBoy (More top-end revs than the circuit).

And as a final tip: Always bring the exhaustport to 67% of the true bore, as it will give you maximum torque with minimum piston(ring)wear.

Would you happen to know the port durations that you cut your kit to? And perhaps compression as well? And maybe ignition timing too if you don't mind giving away all your secrets. Thanks in advance.

@Jesse:

I don't mind giving away the full monty, I don't really have secrets.

I don't have a port-map ATM. I always seem to throw them out, altho I always think: I'm going to keep this map for later referrence... I'll make you one when I have the time (My bike is in parts ATM anyway).

I've never measured compression. My way of checking compression is as follows: Turning the flywheel should be so hard to do that it's impossible to check for spark by hand with the sparkplug in and when you start the bike you need to have your full weight on the seat. That's when I'm satisfied about my compression. Maybe I should measure, as a real compression tester is about 15 bucks or so.

Ignition timing... No clue, I don't do ignitions. I have a friend who is really good at getting it right, so I let him do it. Give me something electric to fix and it'll be on fire within 10 seconds. I do know it doesn't run proper with the key in.

I'd be very interested in the durations in degrees if you could, would make it easy to use it on similar kits. 11k with the circuit huh, what carb is that with?

The circuit stops at around 10.5k, 11k if I got tailwind or going downhill. The lowboy gets it to 11k and 11.5k with tailwinds/downhill.

I use a 21mm Dell'orto PHBG with a foam TNT filter. 45mm HC head and Airsal piston.

I use the Airsal piston because my TCCD piston gave me issues with raising the cylinder enough to clear the head, it uncovered the intake through the piston windows at BDC losing a lot of power and fuel that way. The Airsal piston has the 4 lil holes model instead of the 2 bigger windows, and the holes sit a lil higher than the windows in the TCCD piston.