Recent content by Darryll

No, some other guy. He got pretty deep into it. It was dyno results that interested me.

I guess when I started this thread I was hoping someone had already been down this road and had all the answers. That may well be the case but unless you have a Dyno and went to the trouble of building different combustion chambers designs and testing them you wont have any definitive answers...

Yes that has always been my understanding.

Interesting the 500 piston I have has a flat top. Agreed the sketch I did was pretty piss poor actually. It was a correct ratio but I need to properly map it out and sketch it up. My interest in the 500 shape is simply that the saw goes well and someone was paid possibly 200-300k per year to...

That Partner would be a good mill to have at home in the work shop. My mill will not do heavy cuts at all! I got it to do the type of things I do with saws and other interests I have and it has worked out well. So much of what we do needs a jig. My jig on the lath was fair to average at best...

Yes the 395 can rev quite well. Std they are EX 100. I don't know the 288 at all really but I've been told they run well so I assume they are similar too the 395. What I suggested works to get things moving but they are not optimized numbers. I just know from experience that if you are not sure...

Yes that is a very fair answer. Unless you have a dyno its difficult to quantify your changes definitively you are a bit in the dark. When testing saws there is more to it than how fast it cuts. How they feel and load up etc all counts. My thing lately is ported saw feel slow. Running a stock...

Nice work. I'm not a machinist, in fact I have my own earthworks company and service the rural sector. I always wanted to be a fitter turner and I brought my first lath 30y ago now and a mill not long after. I learnt Fusion 360 back around 2010 and over the years I have got most of it pretty...

For now I have moved away from angled squish bands. I do believe there is some potential there to be realized if I start making my own pistons. I set the head up in this thread pursuing a different line of thought with a square band and the result was encouraging. However I think to get the best...

Cutting the squish band is not the easiest to do I agree. I made up a jig for the lathe but it took a while to setup, certainly longer than it took to do the cut. The CNC has proved to make the process quite easy, I can typically adjust the program and run it in about 30min including setup...

Very similar to mine.

Great read. I was laughing the whole way through it. It seems we are all effected by these simple 2 strokes in the same way. I have a 50mm 372 cylinder that over the past 6 years has gone on and off the saw. It started out ok then went drastically down hill then last year I realized my mistake...

Indeed ! It doesn't take much to set me off on a tangent unfortunately. I do prefer it though when we share our observations of changes we make. I'm sure by now we all know a good saw from and average one. Any conversation that causes me to ponder a thought is a valued one. Its even more...

No its not at that level. But I have downloaded this guys spreadsheets and played with them. I don't recall seeing that sheet though. If his predictions are correct I'm heading in the right direction at 60% though.

Good stuff get after it. In the beginning I did a little bit and the saw went better. So I did a bit more and the saw went better again, so I did a bit more and killed it. Then I killed several chines junk cylinders. I believed it was all about making everything big. Its not, in fact it will go...