03' Yamaha YZ Athena 480F Build

[mstangsteve]

First of all, the bikes not finished!

i took the engine apart the weekend before our yearly Silverlake Dune trip. The mission was to install my Athena 480 BB kit. I found out that this bike had a hotrodz crank and connecting rod put in by the previous owner. the 480 piston wont sit right on the aftermarket connecting rod. The piston teeters on the connecting rod and i cant get the piston wrist pin to line up.

Do to my up coming trip i put everything back together.

While on my trip i would get a slight knocking noise occasionally under load.

Ive torn my bike down again to send the engine to my friends machine shop to mill the under side of the piston to fit on the connection rod. During the tear down i noticed some oil blow-by the timing chain tensioner access bolt. the one with the brass O-ring. Could this bolt being lose cause some sloop in the timing and made a noise complaint. there was not damage to the valve or pistion.

Update soon.....

[grayracer513]

Could this bolt being lose cause some sloop in the timing and made a noise complaint(?)

No. The tensioner would work fine with that bolt missing entirely.

If the piston teeters on the rod, something's amiss. The YZ450 should have an 18mm wrist pin. If the crank is from a 426, the pin would be 19mm.