GT250A Squish

[daxman]

Hi All

Anyone know the squish dimensions for the 250A..?

I have some barrels that came with 2mm skimmed off the top (who knows why?) I am making some 1mm spacers for the base, figuring I can raise the exhaust port by 1mm and reduce squish by 1mm.
But these barrels will need a rebore before I can measure squish more precisely using solder or Plasticine so I'm pre-empting a bit.

Cheers

[dollydog]

hi dax, if you're going to use a 1mm spacer under the base of the barrels, don't forget to factor in you'll be using 2 base gaskets instead of one. you're going to have fun making 1mm spacers, unless you have them cut out on a laser or water cutter. if you're making them by hand you'll need to trap the spacer between 2 bits of wood and clamp in the vice. then do a bit at a time, otherwise you'll keep bending them. i had a lot of fun doing a pair of 2mm spacers just measured my squish band on a gt250 head and it's [as close as i can measure it] 6mm wide, 1mm deep at the outside, sloping down to 3mm deep on the inside. hope this helps
cheers, dd.

[daxman]

HI DD

I started the first spacer by bolting some 1mm alu sheet to some sacrificial 4mm ply and sawing with a coping saw - seems to be working. Ah yes so another base gasket will add what 0.5mm or less? If in fact I'm 'recovering' 1.5mm from the 2mm should make it pretty safe then clearance wise in the head..

[daxman]

.. in fact It should end up to be about 0.5 mm, and I've read that 0.6mm is optimal (no idea why of course.)