2003 yz450f Big bore project problems


1 reply to this topic
  • mstangsteve

Posted October 05, 2012 - 02:46 PM

#1

Im putting an athena 480 big bore kit on my bike. My bike wouldnt start after putting on the big bore kit. I seen some coolant coming down the head gasket while trying to push start the bike. Im a master auto tech and i torqued the head down corrected. further inspection revealed a small crack in the head by the right front head bolt. I already ordered a new head. Do you guys have any tips on torquing 450 heads down? I just bought this bike 6 months ago. It may have always been cracked. this is the sequence i used: in a cross pattern 30 nm, compleatly loosen bolts then 20 nm , final step 180 turn.

i sent my engine out to get checked out by a friend and we lost top dead center on compression stroke. any tips on finding TDC on compression?

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  • grayracer513

Posted October 05, 2012 - 09:51 PM

#2

i sent my engine out to get checked out by a friend and we lost top dead center on compression stroke. any tips on finding TDC on compression?


If you mean that you don't know which TDC is supposed to be the compression stroke, they're both the same until the cams go in. The ignition is triggered at the crank and fires at the same time BTDC on every stroke, so for the sake of timing, there's no wrong TDC.





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