CRF230F/L BBR Piston Ring Gap

[jeffrow68]

Just got a new BBR 67mm piston kit for a CRF230F and dropped it off with my machinist to get it bored.  However, no instruction in the kit specifying ring gap. My machinist needs this specification. Anyone have specs they would care to share? 
 

I did try contacting BBR but no luck.

[adnohguy]

BBR ring end gap clearance is the exact Same as a stocker, Wiseco, Wossner, or Athena.

 

.004 gap per inch (piston diameter) (in inches.)

 

Just now read it on the Wiseco web site.

[Scrammer]

How much Piston to Cylinder clearance is needed ,, or does ring gap determine this ??  or is ring gap already figured in to the final tolerance needed, and used as a final check ?? 

 

[adnohguy]

How much Piston to Cylinder clearance is needed ,, or does ring gap determine this ??  or is ring gap already figured in to the final tolerance needed, and used as a final check ?? 
 

The BBR and Athena pistons are almost identical. IMO, Probably made in the same location?
They are cast pistons and lighter than a stocker. (A stocker and the ProX pistons are also cast)
Generally you can set up a Cast piston on a 230f at .018 cylinder clearance (after final hone)
Some like a little tighter. (Like a stock piston or a pro X.)
Some goes as much as .002)

I set them up at .018 my self

[jeffrow68]

I did find the piston info on BBR’s website for the 67mm piston. The tech info was listed for this piston in a 150F (03-05) which is the same as the 230F all years.