2 stroke intake question

[NACNAC#721]

 I read that it is better to leave the fuel intake port rough for better fuel atomization? Is this true?

[racerxx]

In a two stroke engine I believe air flow is the key to power smoothing out all surfaces will make a difference. I like to clean up the intake, transfer and exhaust ports on any stock cylinder. The performance gain is noticeable I don't modify anything just clean things up.

[billyghog]

The only reason to leave the intake port rough is to encourage the development of a turbulent boundary layer that is less likely to separate and cause a flow restriction than a laminar boundary layer.  The only reason to do this is if you have a lot of bends in the intake tract (typically not an issue in a two stroke) or a diverging profile greater than about 7 degrees (also unlikely an issue in a two stroke, though that depends on the design).  Smoothing the roughness will create an infinitesimal increase the cross section area, so there may be some negligible change due to a lower flow velocity.  Either way, smoothing it out or leaving it at the stock roughness, I would bet neither you nor a dyno would see any appreciable difference.

[NACNAC#721]

ok thanks for the input,appreciate it.

[nickvalve]

Anyone who ports for a living will tell you intake tracts need to have a rough finish and exhausts only need polishing to reduce carbon build-up. By rough I dont mean to clean it up with a hammer and a chisel. 220 grit sanding drums gives a nice finish. The finish promotes atomization and prevents fuel from puddling or falling out of suspension.

[NACNAC#721]

Anyone who ports for a living will tell you intake tracts need to have a rough finish and exhausts only need polishing to reduce carbon build-up. By rough I dont mean to clean it up with a hammer and a chisel. 220 grit sanding drums gives a nice finish. The finish promotes atomization and prevents fuel from puddling or falling out of suspension.

That's similar to what I read online when I did some research Nickvalve. I just wanted to confirm it with the pro ride experts!    It's already rough from the cast process, so I will just leave it alone. I was really looking forward to getting at it with a sledge and chisel 

Appreciate the reply Nick Valve. Any good suspension setups for an 05 yz250? 

[Hack-Man162]

Appreciate the reply Nick Valve. Any good suspension setups for an 05 yz250? 

Yeah, throw the forks in the trash, and get a set of SSS (06+).   

[NACNAC#721]

Appreciate the reply Nick Valve. Any good suspension setups for an 05 yz250? 

Yeah, throw the forks in the trash, and get a set of SSS (06+).   

  tru true

[nickvalve]

Open Chamber KYB is good stuff , it doesnt scare me one bit.

[Hack-Man162]

Open Chamber KYB is good stuff , it doesnt scare me one bit.

I liked the pre-'05 open chamber forks...then they released the '05 experiments....but promptly fixed it in '06.