Broke camshaft/crankshaft teeth

[plowman]

the reason your cam teeth are missing is simple your motor is worn out! the teeth on the cam crank and balancer wear as all the parts in your motor and get excessive lash..clearance.. as well as the bosses in the block, they are cast iron teeth and start beating one another when clearance become to large and they break! and when one breaks so do the rest ,very common on older motors, and especially if one trys to reman there motor and using all the old parts ( witch is not remaning ) 90% of the time the bore is cut with the wrong grit hone( witch eats the rings ) and puts more stress on the bottom end and makes the teeth fail even faster,usually within a year or less. 40% of the core motors i took in this year were from a engine builder in Georgia, 700 bucks gets you a motor, when torn down they have all used internals, china piston and cast rings and piss poor china gaskets,and 25% of them have the cam teeth laying in the bottom! dont think i have had one customer that has got two years out of one of these ( do your home work ) class A "REMANS", I have been telling yamaha for years that they need to sell the crank cam and balancer together, well they listened a little now it comes as the crank and cam together. the 285 and 300 have helical cut gears so this problem don't exist ,hope i have made good sense for all.

[sformal]

Originally Posted by plowman

...well they listened a little now it comes as the crank and cam together.

Thank you for your explanation; talking with friends yesterday, we arrived at the very same.

When I wanted to order parts, I am a bit confused by the camshaft (JN6-12171-00) that have been superseded by 99999-04336-00 which is named "Camshaft & crankshaft". Does it include also the crankshaft (JN6-11400-00)? But at 80.50$ how it can include the crankshaft which is 173.80$?

This being said, what is also strange is that the crankshaft alone is almost the same price than in US when the camshaft/crankshaft is 210$ instead of 80 in US... This price could indicate it also includes the crankshaft.

[raydhd]

Found it Bump