Re: porting picts and success and failures

I have never bored or ported, I did a little case match. I am enjoying thinking about it but can't quite wrap my head around it fully. I am going to try to super stock a tomos. Maybe mess with a morini. I don't want to get too technical. I figure you probably want to work in 3rds. Like intake and exhaust port should be 1/3 diameter of the piston. I figure the spacing on the port map should be in thirds too. I guess it depends on timing? idk im thoroughly confused and it feels good.

btw my tomos goes 50.33333pie and its reliable.

Re: porting picts and success and failures

Chöschi21 C.K. /

I suggest to you that you should start with either first porting a Cylinder with cast iron walls or just try removing material on an old (at best non usable) alu-cylinder with Nicasil plating, Nicasil likes to chip off, so you should get comfortable with it first.

Stock aluminium Puch cylinders aren't Nicasil Plated, their Plating doesn't chip of as easly so if you want to try some porting for your Tomos maybe a stock Puch cylinder would be an idea as long as you can modify an intake and exhaust to fit.

Re: porting picts and success and failures

Dirty30 Dillon /

Why thirds of all things?

I suggest investing in gaskets and start by widening exhaust 1.5-2mm on each side, raising it 1mm, and smoothing the intake for flow. From there, you can test and try more.

Re: porting picts and success and failures

Chöschi21 C.K. /

Ports third as wide as the Piston does make sense, that's 66.6666...%, you shoud, for a 1 Piece port go for about 65%, never much over if you want something reliable.

Re: porting picts and success and failures

Hell may aswell throw my tupence in the mix

I’d say attack the piston first.

Removing 2-5mm from the intake side of the piston.

On the crown of the piston. Some filing in front of the exhaust port to give some more exhaust timing.

Smooth everything around the wrist pin of the piston. On the side of the exhaust skirt some removal of the side of the piston skirt.

After this a little 1-2mm widening of the exhaust.

That’s about as far as I’ve taken mine.

Re: porting picts and success and failures

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> Why thirds of all things?

>

> I suggest investing in gaskets and start by widening exhaust 1.5-2mm on

> each side, raising it 1mm, and smoothing the intake for flow. From

> there, you can test and try more.

Yesth....I usually start with widening 2 and raising 1. Measure and check the ring pin won’t snag the exhaust and make some final porting from that.

Now I just draw on it with a marker and go at it. With time it gets easy.

You really don’t want the width to be more than 65% of the bore. I know there is an actual # in the 2 stroke tuning handbook. I can remember what it is. One of the reasons why puch Polini’s rip so hard out of the box is they are already 62% of the bore...... don’t quote my #s I am sure someone knows the real percents.

Re: porting picts and success and failures

I would like to see pics of a successfully ported stock Puch high-torque cylinder, and what improvements were gained?

Re: porting picts and success and failures

> Seth B Wrote:

> -------------------------------------------------------

> I would like to see pics of a successfully ported stock Puch high-torque

> cylinder, and what improvements were gained?

No pics but 50/50 is very achievable if not uper 40s

I like to port the open transfer kits. Easier to squeeze out extra revs. Some of them you have to knock out the metal restricter in the intake but it is worth it!

If I was doing the Colfax Killer I would do a ported open transfer kit with a 15 bing and a buttturbo.(edited)

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