SPI Piston Specs
Im rebuilding a 1998 Polaris XLT SP 600 due to low compression. Help me here guys, According to Polaris my end gap installed on OEM pistons are .008-.020 and average between all 3 cylinders was > .036 on top ring and >.026 on bottom rings. The compression on all 3 cylinders was 65 psi. The pistons show blow by and deep grooves on skirt and above rings which to me say either not enough lubtrication or to rich and washing out cylinders. Now I ran into a good deal on SPI pistons and sent them to machine shop to have cylinders bored .020 over but there was not a spec sheet. So I called around and the good people at Hi Performance Engineering sent me a spec sheet they had found. My bore before honing is 65mm and with new pistions will be 65.50 mm and SPI state bore size of 50-65mm should have piston to cylinder of .004-.005 for liquid cooled engine and state "two ring piston end gap should range from .010 -.035".
1. The machine shop thought the .004-.005 was a bit odd for a liquid cooled and was wondering if anybody had any thought with SPI piston kit?
2. The installed end gap of .010-.035 seems broader range than original Polaris specs?
3. Can the 4 line oiler be adjusted or is it set to pump a certain amount of oil during operation?