Porting

[olyman]

What’s the point?

run your teeth over the whole forum....pride....

 

[Huskybill]

run your teeth over the whole forum....pride....

What are you talking about?

 

[Terrence Jefferson]

New to porting or want to port take note.[/QUOTE]

I'm new to most all of this and I want to learn but I prefer to start at the beginning and learn a little theory of why to do it and how to do it. And what numbers to look for on a timing wheel . So far I haven't seen much for me to take note on.

 

[CausticUC]

New to porting or want to port take note.

I'm new to most all of this and I want to learn but I prefer to start at the beginning and learn a little theory of why to do it and how to do it. And what numbers to look for on a timing wheel . So far I haven't seen much for me to take note on.[/QUOTE]Theory helps some, depends what you are doing though.

I'd recommend starting with blueprinting, which means you are cleaning up casting and manufacturing flaws. If you can cleanly blueprint, you should have enough control to start doing heavier cuts without screwing them up.

Blueprinting also usually does not require altering timing much, if any; you are just maximizing the designed specs.

It will also give you the skills to mark your transfers to check them, which is critical for good porting.

 

[Terrence Jefferson]

CausticUC. That's helpful to porting and learning how to Port. Thank you

 

[drf255]

If one doesn’t want to use a degree wheel, there are port timing by height calculators which are surprisingly very accurate.

Lambretta and Torquesoft are two calculators that are available free online.

I also would like to see some of the OP’s porting pics.

 

[cuinrearview]

If one doesn’t want to use a degree wheel, there are port timing by height calculators which are surprisingly very accurate.

Lambretta and Torquesoft are two calculators that are available free online.

Blind monkey included?

 

[drf255]

Blind monkey included?

Extra fee, plus toilet paper.

 

[drf255]

I’m just starting out too. Here’s a pic of another Ex-member’s porting. I call it “the unicorn”

 

[drf255]

@Huskybill

I’d like to learn, please show us some port pics and why you chose to go with that certain method and timing changes, etc...

 

[Ronie]

Huskybill, if the goal of this thread is to help others that are new to porting you should post some pics of the cylinder that you spoke of in your carbon thread and explane what you did and why you did it so that people like me can get a better understanding of the whole process.

 

[NSEric]

Imo nothing regarding porting dirt bike engines applies to chainsaws.
Everything is different, show me a chainsaw with reeds and a powervalve.
Also no one ever ports a bike cylinder without replating it afterwards so the nikisal wraps into the ports, on saws we just sand that part smooth but a bike would peel the plating off and blow up in minutes if you did that.
In fact most porting done to bikes now is to make them run better at rpms lower than chain saws idle at...

Im a hack when it comes to porting saws, I go for the quick easy stuff that works. I also don't use a degree wheel so I don't raise the ports more than the thickness of the base gasket I take out so im not messing up the timing. On some work saws you don't want to raise the ports at all, they're not all the same.
I watch a lot of youtube videos on porting saws, 90% of the gains are the easy stuff, no base gasket, slightly wider intake and exhaust, open up the lower transfers, advance the timing and muffler mod of course. Unless your racing saws I wouldn't even worry about the last little bit. I wouldn't polish the ports in a work saw at all, I use the pink smooth wheel that comes with most dremels last, that's polished enough, after a few tanks of gas the exhaust port will be covered with carbon and the intake ports are best left a little rough anyway.

 

[Huskybill]

Nseric, im working on older Husqvarna and honda bikes with steel and cast iron sleeves not nikasil. Ive ported nikasil cylinders in the past too. You don’t have to replate the cylinder I’m not touching the bore I’m cleaning up the runners that go into the crankcase depending what design you have. I’ve seen the exhaust and intake ports raised and lowered more than I’m doing on the saws. After all it’s a woods saw for work. A two stroke engine is a two stroke engine it all breathes and exhausts pretty much the same. I don’t believe in leaving the ports rough. Roughness make the carbon stick. I wish I took pics of the cylinder I just ported the exhaust was carboned up really bad. I never seen one this bad the carbon was 1/16”+ thick. I have no clue what two stroke or ratio they were using.

 

[full chizel]

 

[NSEric]

I work on much newer bikes than you do, we don't port em as they're too fast stock lol.
My gasgas 250 had the corners of lower transfers filled in making the transfers smaller to aid low rpm power and limit mid range power by the PO, it worked awesome.

 

[Huskybill]

Here’s a pic. I see some fine work porting and some hammer and chisel work here. Do it right get a Dremel. I used a 1,000 rpm black n decker drill when porting it worked great in the beginning for porting around valves and opening intakes and exhausts on drag racing heads. My point is even a drill with the carbide bits I listed will work for your first try.

On the chainsaws I don’t touch the transfers in the cylinder I just open up the intake and exhaust ports. I copy what was done by the husky rep when I measured his cylinder when i reassembled his 2100. He hogged out the intake and exhaust port more than I do.

 

[Huskybill]

I work on much newer bikes than you do, we don't port em as they're too fast stock lol.
My gasgas 250 had the corners of lower transfers filled in making the transfers smaller to aid low rpm power and limit mid range power by the PO, it worked awesome.

Newer bikes are slower on the top end, because of the power valves. Power valves raise and lower the top of the exhaust port. Raise the exhaust port Sound familiar?
But they lose their top speed in the process. We tested a kx250 and she ran out of speed at 85mph. The huskys have a rep for top the end speed. The older huskys are 100 mph desert racers. I’m not sure we’re the new European bikes fall in speed wise but I like seeing the older huskys beating the jap bikes in the straights,

 

[Huskybill]

My thoughts are lowering the intake port is like advancing advancing a high lift with more duration cam in a four stroke engine. More fuel is being sucked into the crankcase. With the exhaust port raised it opens sooner so it exhausts more spent gasses sooner. I believe the exiting gasses also helps sucks the fuel into the cylinder. There’s a mili second we’re where the piston moves down where it’s exhausting the hot gasses were the intake is drawn in from the tale end from of the leaving hot gasses. The gas port opens sooner if we raise the exhaust port.
Having a chamber/pipe helps this process. And modifying the stock muffler improves this action.

Here’s my carboned up cylinder with the porting in the rough. in pic 338.2 kb see the fine cross hatch in the cylinder.

 

[Ronie]

Looks good to my untrained eye. Thanks for posting pics.

 

[Huskybill]

Thanks it’s not done yet only roughed in. The lower pics the cylinder is going on my 2100 rebuild.