Never had a problem with Athena gaskets. They are used on my Starlet necessary when trippling the power output of the old engine.
Sounds like either not fitting correctly, or head and barrel not skimmed properly.
Fitting means retorquing after running the temperatures.
Try here @ConnorDTR http://www.bikerpartshop.com/en/91-blackbird-racing-stickers-seat-cover-for-yamaha-dtr-125-dt125r.html?ps_full_site=1 that's the only link I have but once there have a look on the stickers section they had some nice ones the last time I was on! I found some decent graphics kits for the DTR on eBay there's a guy selling mx style ones last time I searched for DTR graphics some had numbers with them and you can customise the number and add a name etc think the kits where £99 or best offer so quite expensive .
@dan28 Cheers buddy, but i've gotten it sorted now. Appreciate the offer.
Found an m12 washer fits, however it is too wide so it has to be ground down. But I got a washer from my college which was off of another bike that fit
@Biker_123 They're mental, only blipped the throttle in second gear at like 10 mph and it just wants to shoot off! Deffinitely what i would upgrade to.
@Uber_Beluga Don't be envious! As my luck goes this will last all of 2 weeks haha