250 Deck Height

[Chakka]

I am setting up the top end on my Hare Scrambler and searched the archive to no avail. I have an Elko piston and need the deck height measurement. The shop manual lists heights for 2 different style pistons and I am not sure which the Elko falls under.
Thanks in advance
Chris

[DKWRACER]

Chris, I am pooring thru manuals, seems like .040 to .047 X dimension will get you within reason.
The piston clearance can be as low as  .002, but I do not rec. this.

...... the heat causes pistons to grow where the mass is, genererally @ the top, pistons are not true to bore, they do have non-linear proportions..they are tapered. Just measure one!

I rec. Swaintech coatings, even on new pistons to control the heat. with a ring end gap of .012 to .018 and a piston to bore fit of .035, you should be well within the the "envelope". Don't forget the oiling hole to cool the exhaust port bridge ...

 Tom Brosius

[Rain Man]

My manual states that dimension X  for engine type 54-250ccm
Piston #1274 =.9mm  and   #1274a=1.2mm. The american standard conversion of that = .0354" and .0473".  I'd shoot for .040  if gaskets permit.

Raymond
 Down East Pentons

[Chakka]

Thanks Guys, the two piston styles listed in the shop manual had me confused. I'm off to the workshop to stack up some base gaskets.

Chris