Athena 280 big bore gasket - is size really everything?

Hi there.


I have a 2004 CRF250X into which I'm trying to fit an Athena 280 big bore kit. All good up to the point when I noticed the valves fouling on the piston when turning over.


I bought the kit from ebay without gaskets (naively expecting the standard Honda ones to be the same) and am now wondering....


So, my question is should I be fitting different gaskets and if so a). which ones do I need, and B). where can I get some in a hurry?! I'd read somewhere that the Athena ones are thicker??


I'm in the UK and so far am having trouble finding a distributor that stocks any Athena kit. I have emailed the good folk at the Thumpertalk shop for their thoughts and am awaiting a reply but in the meantime if anyone can offer any advice I'd be really grateful.


Many thanks 


PS if I buy from the US, any ideas about delivery times etc.

Hi the valves will only foul on the piston if the cam is timed way of or you put the piston in the wrong way around the larger cutouts to face the back of the bike intake side,as for the gaskets try off road only

they sell the athena kits ect.Martin.

For big bore kits gasket size is everything.


Good you checked piston/valve clearances, besides valve timing too thin a head gasket can also cause valve/piston problems.

Thanks for your help and advice. I finally got hold of a proper Athena gasket kit (from Off Road Only as suggested) - really helpful bunch and sent overnight arriving on a Sat morning! Re-checked timing and set about installing as I write this so hopefully no nasties. Testing at the weekend so watch this space!

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