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Discussion Starter · #1 ·
I have just replaced the pistons in a 71 cb450 engine. I have the cylinder block and head back on but I am running into a problem when getting ready to get the cams lined up so I can put the cam chain on.
When I try to turn the alternator flywheel to find TDC the wheel will not turn 360 degrees. It's more like 300 degrees then it stops.
What am I missing?
 

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547 said:
I have just replaced the pistons in a 71 cb450 engine. I have the cylinder block and head back on but I am running into a problem when getting ready to get the cams lined up so I can put the cam chain on.
When I try to turn the alternator flywheel to find TDC the wheel will not turn 360 degrees. It's more like 300 degrees then it stops.
What am I missing?
I don't think you're "missing" something, I think maybe you're hitting a valve with a piston.
I usually have the alternator on or near the mark prior to even putting the cams in.
If this is the case, you may have already bent a valve, they bend real easy.......

I see you're just north of Lansing - you could haul the engine down here to me, we could check it out.....
 
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Discussion Starter · #3 ·
i have been watching the left piston through the sparkplug hole when i turn the flywheel slowly with a wrench. the piston rises and falls alright and then stops near the bottom of the cycle. when it stops the right piston is near the top of the cycle.

i'll have to see if i can find the time to get it down there.

i think i am going to remove the head again to check out the valves and to see if i can get a turn on the flywheel.
thanks
 

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547 said:
when it stops the right piston is near the top of the cycle.

thanks
Well, yeah, it's 180 degree twin, so that's the way it should be......

Bring it on down, we'll go through it together - if it looks good I'll show you how to do it and connect the cam chain for you.
 

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It WILL be worth making the trip.... Bill is the "OFFICIAL" site 450 expert..... :D :D
 
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Discussion Starter · #6 ·
i will keep that in mind and i really appreciate the offer and i am sure i will hit you up in the future. but my warehouse closed so i only work here and there on roofs so no money and no gas. but definitely in the future.

the right side intake valve was open.
i got the cam index marks lined up and i am ready to put the cam chain on.

i read your post on 450 cam timing and it is helpful but fills me with dread too.
once all valves are closed and index marks are lined up on the cams and index mark on the flywheel is at LT then it is ok to put the cam chain on. is this right
 

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Please re-read Bill's proceedure......All the valves won't be closed at that position, the Right exhaust will be under some pressure....
 

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547 said:
i see and it is. left intake is open too. is that ok? there is no contact with the piston.

Then why was your crank refusing to turn??
I think it may be too late, that you've already bent a valve..........

I don't recall saying anything about asking you for money, did I ?
 
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Discussion Starter · #10 ·
no, i meant no money for gas for my car to get to where you are.

this is what what i did when the engine wouldn't turn.
took off the head and rotated the cam on the intake side which closed the open right intake valve
the engine then could turn

i think i might just put this one away until after the new year and make the trip down to see ya so i can get it done right.
 
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