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Author Topic: Cylinder jugs/block not bottoming out  (Read 1104 times)

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Offline Moffman

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Cylinder jugs/block not bottoming out
« on: May 26, 2015, 10:23:30 PM »
79' CB650, having an issue with getting the cylinders to sit flush with the block, it has about an 1/8th of an inch gap on both sides. Pistons appear to be installed correctly so the only thing I can imagine causing a problem is the cam chain tensioner. But Looking at it from underneath it looks right so I'm a bit confused on what's holding it up. Anyone ever run into a similar issue?

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Offline scottly

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Re: Cylinder jugs/block not bottoming out
« Reply #1 on: May 26, 2015, 10:29:52 PM »
Dowel pins properly aligned with their holes? They're a snug fit...
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Offline Moffman

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Re: Cylinder jugs/block not bottoming out
« Reply #2 on: May 26, 2015, 10:34:30 PM »
I'll double check again tomorrow but I'm 99% sure they were in right. Thanks
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Offline scottly

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Re: Cylinder jugs/block not bottoming out
« Reply #3 on: May 26, 2015, 10:43:01 PM »
Make sure the block is not cocked to one side, jamming the dowels; it needs to go down evenly.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Cylinder jugs/block not bottoming out
« Reply #4 on: May 27, 2015, 12:26:03 PM »
750's use 2 different length dowels. Not sure about 650's. using the right ones?
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Online PeWe

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Re: Cylinder jugs/block not bottoming out
« Reply #5 on: May 27, 2015, 01:55:07 PM »
I do not know if it look as on a CB750.... Cam chain tensioner part into case seated OK?
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Offline Moffman

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Re: Cylinder jugs/block not bottoming out
« Reply #6 on: May 29, 2015, 04:07:52 PM »
Finally got a chance to take a look at it and didn't have any luck. Both oil control dowels are seated right, I removed the cam chain tensioner to see if that was the problem and it's still not going down all the way. I can't for the life of me think of what else could be preventing it from seating.

Here's a pic of it, there's like an 1/8th of an inch on both side and I pulled it up again to take a picture of the dowels.

Maybe it's an o ring?
« Last Edit: May 29, 2015, 04:10:11 PM by Moffman »
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Offline calj737

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Re: Cylinder jugs/block not bottoming out
« Reply #7 on: May 29, 2015, 04:16:01 PM »
Has the head or block been milled? If so, the holes are now too shallow for the stock length of the dowels and there will be separation. To resolve (if this is the circumstance) the dowels need to be machined (shortened) the corresponding amount.
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Offline Moffman

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Re: Cylinder jugs/block not bottoming out
« Reply #8 on: May 29, 2015, 04:24:08 PM »
Quote from: calj737 on May 29, 2015, 04:16:01 PM
Has the head or block been milled? If so, the holes are now too shallow for the stock length of the dowels and there will be separation. To resolve (if this is the circumstance) the dowels need to be machined (shortened) the corresponding amount.

You would think so but no, only the cylinders were honed, everything else was just razorbladed.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Cylinder jugs/block not bottoming out
« Reply #9 on: May 29, 2015, 05:26:31 PM »
Show us a picture of your cam chain tensioner positioning.
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Offline Moffman

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Re: Cylinder jugs/block not bottoming out
« Reply #10 on: May 29, 2015, 05:51:12 PM »
I just pulled it off again and I'm pretty sure it's from the cylinder base o-rings. My thought is as I torque down the head bolts that they will seat into their grooves. I've tripled checked the tensioner is right and tried without it.
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