Athena 300cc Kit for 2009 TE250

Anyone fitted one? My TE has one fitted (83 mm bore) and now I'm looking at reassembling the engine, the deck height is nowhere near that suggested in the workshop manual. I've found the Athena instructions and no mention of deck height. Any feedback appreciated.

OK, so I've sent the head away because of a burned exhaust valve and a bit of marking on the face from the old gasket(s). The skim was 0.1 mm. The head guy did a chamber measurement for me after skimming, 13.4 cc. I've done multiple deck height measurements at 4 points round the piston, 0.6 mm seems the best measurement. I've also done the piston chamber measurement, the best I can get is 5.65 cc.

Add it all together and I get a 12.14:1 theoretical CR. I'm guessing that the barrel will squeeze up a bit when the head is on because all I can do is push down on it manually while measuring. A bit of googling gives a 30% comprssion on the 0.4 mm base gasket, so 0.12 compression which would make the deck height .48 mm.

That gives me 12.4:1. Reading some old posts, the original CR for the 250 was 12.9:1 and the Athena kit lowered it a little to 12.5:1, so I'm in the ball park. 0.1 mm gives .25 on the CR, so even if I've got something wrong, I'll be going from 12.5 to 12.75 CR, which is OK.

297 cc is the stated volume. I checked the CR because the deck height was not as the Husky manual, which must be to compensate for the smaller combustion chamber on the 250 head.