04 450 maintance

i am in the process of getting my 450 re-built (piston/rings) for maintenance... i raced this bike last year and the yamaha mechanic suggested replacing the lower connecting rod bearing as well.... again this is preventative maintenance so i'm not sure if this is needed....

i change my oil every three rides and the filter every six...(practice 4x week and using the bike hard)

what's your guy opinion... would you replace the bearing as well or is it a unnecessary??

well i would say just compare the price of the new bearing... what 25$? compared to the price of damage it can cause if it fails... would have to resize the rod or cut the crank or get a new crank... i would say go ahead and replace it just for the peace of mind that you have a new motor essentially and should be good to go another year..

i am no pro mechanic but that is what i would do!

good luck

You should be able to check the bearing by measuring any slop/movement to see if it needs to be replaced.(not sure what the specs are) A bearing may be only a few bucks, but bear in mind that you would still have to split the cases, remove the crankshaft, and get the crankpin pressed out and re-assembled. Labour isn't cheap either!

I agree with Jonesy, have your mechanic show you the play in the rod that suggests a new bearing. If you keep the oil clean, and change it regularly, this shouldn't be a maintanence issue like rings, camchain, etc.

The cost to split the cases will be the issue, the bearing is relatively cheap.

I don't know of anyone ever experiencing crank bearing failure with good maintenance in all my years.

Ive had a crank seize, they give very little warning and when the bearing goes it will

usually take the crank pin with it..its like a hay fever tablet, take one and you will never know if you needed it, dont and your life's a misery.

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