Powerporting Vs 360 degree

[Jazzy]

right, bear with me and be gentle

My understanding is although termed as 360 timing, this is misleading as although the inlet port is open 360 degrees the reed controls the inlet duration and this inturn is governed by the pressure difference between the crank case and the outside world.

my questions are,
1. is it possible to calculate the the actual duration that the reed is open.
2. is this dependent on Transfers and/ or crankcase Volume
3 does this value alter with engine speed.

cheers

[Knowledge]

At 6,000 rpm, the duration of the opening of the reed petal is 100th of a second.

In reality, I wonder if the reed shuts at such speeds.

With the right combination of exhaust, primary compression and transfer timing, an engine will run without the reeds in place (assuming you could get the engine to run-up to that speed without any petals fitted). Some two-strokes that are intended to run at one-speed are built like this, and brought up to speed using compressed air.

I'm not sure if this information has helped with your thoughts about 360 degree Vs power-porting

[Jazzy]

At 6,000 rpm, the duration of the opening of the reed petal is 100th of a second.

In reality, I wonder if the reed shuts at such speeds.

With the right combination of exhaust, primary compression and transfer timing, an engine will run without the reeds in place (assuming you could get the engine to run-up to that speed without any petals fitted). Some two-strokes that are intended to run at one-speed are built like this, and brought up to speed using compressed air.

I'm not sure if this information has helped with your thoughts about 360 degree Vs power-porting

Not helped much, but I,m sure i will drop it into conversation next time I,m on the pull. I,ve heard 2T tunning makes the girls Moist

[Muppet]

top question; ya just need someone whos done it to a lamby pot; not just read up on it an ya mite get a useful answer

[sean brady scooters]

never tried it myself on a lamby ,but check out A graham bells book (performance tuning in theory and practice )pages 63 to 66..

[Jazzy]

In my garage i have a suzuki 1974 rl250 which is almost identical to a ts1. but is power ported rather than 360. the performance figures also are almost identical to a ts1
I have a Ts 200 which has suffered from piston faliure in the past (twice).
really dont want to go the race tour route. and was looking at this as an option but not sure what durations to go for.
i could just copy the RL.

Alternativly

1. has any one had any luck putting a window in any 66mm piston, if so what was it.
2. Know of a suitable 66mm jap piston that runs 18mm gudgeon pin.