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Post by retardninja on Jul 21, 2013 6:48:24 GMT -6
I talked to my mechanic and told him how my scooter still didn't have compression after the bbk install and he immediately told me my crank bearing needed to be replaced.
I know he is a good mechanic but has anyone ever heard of this before?
What special tools are needed?
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Post by tvnacman on Jul 21, 2013 9:04:57 GMT -6
if the pistion is running up and down the cylinder , you should have compression . Even a crank with a bad bearing will still move the connecting rod up and down the cylinder . A broken crank could cause no compression .
Did your scooter ever run after the BBK install ?
John
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Post by retardninja on Jul 21, 2013 9:32:02 GMT -6
No it has not run since the install and I've triple checked everything. I've tore it down and reassembled it 3 times. The piston is running up and down just fine. If the crank was broken then the piston wouldn't move at all right?
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Post by Alleyoop on Jul 21, 2013 10:04:20 GMT -6
Did you install the rings correctly? Did you adjust the valves and time it right?
If you never done it before and you "THINK" you did it right that is NOT GOOD ENOUGH. The ring gaps could not be aligned correctly the gaps could be one above the other and that will loose compression or the gap aligned with the wrist pin etc..
Alleyoop
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Post by retardninja on Jul 21, 2013 10:34:41 GMT -6
The rings were pre-installed so I assume they were done right, I could double check their alignments though. I don't know exactly what the wrist pin is so I can't answer that. I have followed the timing steps that I have seen on the forum here.
I'm taking it apart again to check the gap alignments and setting them perpendicular to the wrist pin.
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Post by Alleyoop on Jul 21, 2013 10:58:37 GMT -6
AH, the rings where preinstalled, but they move around very easy so handling the piston can easly shift them around. They are in grooves so that could be your problem. The Wrist Pin is the BIG HOLE on the SIDE OF THE PISTON that the CRANK is attached to.
Alleyoop
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Post by Alleyoop on Jul 21, 2013 11:19:39 GMT -6
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Post by retardninja on Jul 21, 2013 11:22:24 GMT -6
Ok wellI have taken off the valve cover and the rocker arm assembly. so basically the cam is not tied down. Just out of curiousty i put my finger on the spark plug hole and it has more compression than it did while it was assembled. I only could set the bottom valve at .003 and I had to fight to get that (it's a tight fit) I know it's supposed to be .004 but with out filing down the pin on the valve spring restrainer washer thing I can't open it any more.
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Post by Alleyoop on Jul 21, 2013 11:37:54 GMT -6
WHAT!!! Take a picture of the setup on top with the Valve cover off, Something is NOT RIGHT UP THERE. ARE YOU SURE your doing the valve gaps when the PISTON IS AT TOP DEAD CENTER and the ROCKERS ARE OFF THE HIGH LOBES OF THE CAM?  Alleyoop |
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Post by retardninja on Jul 21, 2013 13:46:37 GMT -6
I am working on uploading a video of the timing set up I have done. I was going to use a Dremel and relieve the obstructing points shown in this drawing Attachments:
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Post by retardninja on Jul 21, 2013 13:58:19 GMT -6
Here is the video. I just cant see that I am doing anything wrong...
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Post by tvnacman on Jul 22, 2013 18:30:13 GMT -6
do you have a tork wrench ? How did you hone the cylinder ?
John
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Post by Alleyoop on Jul 22, 2013 18:48:24 GMT -6
BUMMER!! I think you got the wrong valves or head, there are two heads one has 64mm valve stems and one has 69mm valve stems. Try the other head. Alleyoop  |
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Post by Alleyoop on Jul 22, 2013 18:49:48 GMT -6
Looks like you have everything correct it is the parts that are the problem: I think you got the wrong valves or head, there are two heads one has 64mm valve stems and one has 69mm valve stems. Try the other head. Alleyoop |
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..BAD TO THE BONE..
