back bearing

when the seal goes the water gets in a its gone soon after. thats honda


also what jet size are you running, and does your atv miss or stumble at 1/8 throttle ????

actually i took my jet kit out. and my reason for that is my stock jet had more power than the jet for my altitude level (low) and with the bigger jets it did just like you said it kind of spit and sputtered at 1/8th and 1/4 throttle and i just didnt like that. the thing that really makes a difference is the motor work and when you say decked head what are you saying

i fly cut .010" off the head gasket area to increase the compression

this is one of the main bearings that need to watched and replaced when any slack shows. If left to long the race will cut in the axle and weaking it causing it to shear off.

Vet another way to raise the compression is to split the head gks and only use half of it. Just drill the rivet out and seperate it. It will still seal up good.

oh i had that done as well i dont think that made that big a difference though it is the actual head work and piston that made the difference

every little bit helps. i like to fly cut because it adds a new clean surface to the head and if there was a warp it gets rid of it too.
i ve seen nasty burn thoughs of head gaskets on atvs and i dont think i would be able to spit in half the machinist in me wouldnt let me.