Is Anyone Interested In Seeing How I Port A 372XP

[Officer's Match]

In your dream was it Red and Black?:msp_ohmy:

That would be one of those dreams you don't talk about in public.

 

[bcaarms]

That would be one of those dreams you don't talk about in public.

You're right on that one. I can wait till it hits the shelves, but I would like one in Red and Black.

Your dog avitar is beautiful. Hope he or she is doing well. My malamute is back in his baby play pen for six weeks recovering from his second ACL tear surgery. This time the right leg. In about 5 weeks I'll have him back with a full bionic rear suspension.

 

[Officer's Match]

You're right on that one. I can wait till it hits the shelves, but I would like one in Red and Black.

Your dog avitar is beautiful. Hope he or she is doing well. My malamute is back in his baby play pen for six weeks recovering from his second ACL tear surgery. This time the right leg. In about 5 weeks I'll have him back with a full bionic rear suspension.

Thanks, Baron is doing great. I grew up having Malamutes at home. Beautiful and hard headed dogs. Best wishes to yours.

 

[MGoBlue]

Hopefully you can see the bevel/radius I put on the port edges in this shot.



I think the life of the rings depend a lot on how slick these edges are. The last step is fine ScotchBrite around a bore hone to really get this area smooth.

Thanks for showing the bevel. I'd love to see a vid of this but I have a much better idea of how far to go. What about polishing the exhaust port, is this in a finished state?

 

[Mastermind]

That is as polished as I go.

 

[814hammer]

I have......and I use it on all the 372s I build these days. I also use it in 346s. Not all jugs will have enough meat there though.

Here's some pics of the finished jug.

I use a 180 grit diamond egg shaped burr to get this finish. It's not real rough, yet I like to think it promotes atomization. I use this finish in the lowers and intake, but use a smoother grit in the uppers.

Why not polish smooth cause not as big of gain for as much time polishing real smooth I always thought the smoother the better stuff flows but I know nota about porting

 

[moody]

Why not polish smooth cause not as big of gain for as much time polishing real smooth I always thought the smoother the better stuff flows but I know nota about porting

Polished aluminum doesn't dissipate near as fast as a surface with texture. Which means that it gets hotter. My ultimate goal is for the saw to run cooler. So I don't polish the exhaust port. I use 120 grit and get uniform surface.

Sent from my SM-N900V using Tapatalk

 

[nmurph]

The exhaust should be smooth.

An air cooled two stroke derives its cooling from expelling the exhaust as quickly as possible and by the quenching of the incoming fuel/air charge. Intakes are left with a little roughness to promote a tumbling of the incoming air/fuel and a more complete burn of the mix.

 

[Mastermind]

If you do a bit of study you will find a term known as a boundary layer.

Learning to study the task at hand, and comprehend all you find is a wonderful tool that the Internet has made available for us all.

 

[814hammer]

If you do a bit of study you will find a term known as a boundary layer.

Learning to study the task at hand, and comprehend all you find is a wonderful tool that the Internet has made available for us all.

I guess I could have not been so lazy and just searched it myself instead of asking lol

 

[Mastermind]

I get PMs all the time. Hey Randy tell me all I need to know about porting a saw in two paragraphs or so.

I'm sorta snappish about that lately.

It took some serious study to learn how to do this well. Tough to condense it down and pour it in a feller's ear.

 

[nmurph]

I get PMs all the time. Hey Randy tell me all I need to know about porting a saw in two paragraphs or so.

I'm sorta snappish about that lately.

It took some serious study to learn how to do this well. Tough to condense it down and pour it in a feller's ear.

Could you tell me how to make pie? Just a Cliff's Notes version will work.

 

[Tree Sling'r]

I get PMs all the time. Hey Randy tell me all I need to know about porting a saw in two paragraphs or so.

I'm sorta snappish about that lately.

It took some serious study to learn how to do this well. Tough to condense it down and pour it in a feller's ear.

I learned from blowing my own stuff up, you d say I have a small fortune invested in the simple methods I use.

 

[814hammer]

I could have looked it up but also figured I'd ask some ppl that know what there talking about cause one of my saws I was cleaning it and polished the heck out of intake and muffler ports thinking gas and air would flow in faster and also same as flowing out faster being smooth but looks like I will be roughing them up a little thanks for the info everyone

 

[Mastermind]

Hey Neal........two cups of "I have a potty mouth" and a heaping.....

 

[nmurph]

Hey Neal........two cups of "I have a potty mouth" and a heaping.....

Ahhh, secret family recipe....you tease. I thought we were closer than that.

 

[Mastermind]

You'll have to call me Neal. I can't be posting that stuff on the World Wide Webs.

 

[masonh]

I am new to saws but not new at all to modifying motors and racing cars. And the guys above are correct, you don't want a super smooth finish on the intake side. You need a little roughness for intake and smoothness for exhaust.

I would defer to the saw experts for now if I wanted my saw ported because I have never done one and have actually never done motor work to a 2 cycle motor, but if it were me doing the work I would probably use a 60 or 80 grit sand roll and make sure the sand marks go against the flow for increased turbulence. Otherwise the fuel will just roll slowly down the smooth surface at a pace slower than the air. Like I said I have never worked on a 2 cycle motor so take it for what it's worth.

Maybe if he gets caught up sometime soon, I'll send my saw into Mastermind and request an even rougher port job with a 60 grit roll (if he is willing to try after I sign the necessary waivers) just to see how it turns out.

 

[814hammer]

When he gets caught up were he is taking work again I have a few Jonsered I will be sending him it just gives me time to get money saved to get. The 3 or 4 saws done can't. Wait

 

[Jacob J.]

You'll have to call me Neal. I can't be posting that stuff on the World Wide Webs.

How do I knife-edge my connecting rod again? Can I make a new crankshaft out of an old fence post? Will the carburetor off my Wood Shark work on my 088?

I wanna sharp edge on that rod to cut through that dang boundary layer.