Cam Chain Tension Blows out of Cylinder block

  • MDZ1rider
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Re: Cam Chain Tension Blows out of Cylinder block

01 May 2015 08:42
#670276
Sorry. I knew I had seen a post from you on a different subject, but couldn't remember the details. We've all made mistakes, and all learned from them. As Steve said, repairing stripped threads is just part of working on 40+ year old bikes. I buy helicoil inserts in bulk packages.
The tensioner bolts are 6mx20. I believe they are standard 1.00 pitch thread. Fine would be .75. Look for 6x1.0 inserts for what ever thread repair method you use.

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  • SWest
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Re: Cam Chain Tension Blows out of Cylinder block

01 May 2015 10:39 - 01 May 2015 10:40
#670287
I don't use a special drill bit. The hole is large enough to use the tap. I dip it in grease to lubricate the threads and pick up the filings. If a small amount of filings fall onto the engine, they will be blocked by the strainer and filter. To completely disassemble the engine for two threads is just silly. That's the way I do it, you can do it the way you like.
Steve
BTW, tapping threads mean doing it in stages, not all at once.
Last edit: 01 May 2015 10:40 by SWest.

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Re: Cam Chain Tension Blows out of Cylinder block

01 May 2015 11:19
#670294
It may be possible to drill and tap the threads for a heli-coil with out disassembling the engine, but I would wouldn't do it for another reason. Why did this happen in the first place? I'd at least want to have a look at the roller on the tensioner assembly. Tearing it apart is the only way. Unless you know you over torqued the bolts and stripped the threads, something else caused those threads to rip out. There's only one way to find out.

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  • bluezbike
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Re: Cam Chain Tension Blows out of Cylinder block

01 May 2015 11:35 - 01 May 2015 11:39
#670297
Just throwing a thought out there.....the amount of force needed to punch out the tensioner would be huge, as you mention there was different tension in the cam chain .....could it be that the chain had somehow jumped off the center sprocket on the crank or wasn't installed correctly? Then when starting the bike that chain could have whipped around or jammed subsequently punching out the tensioner?

I agree with MDZ......I would strip the motor down again to check nothing else went bad in there
79 KZ 1000 LTD
77 KZ 1000 B1 LTD (awaiting electrical resurrection)
Last edit: 01 May 2015 11:39 by bluezbike.

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Re: Cam Chain Tension Blows out of Cylinder block

01 May 2015 12:59
#670311
To discover this, all that needs to be done is remove the head. You can also look down and see what's happening.
Steve
The following user(s) said Thank You: missionkz

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  • Yorkie
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Re: Cam Chain Tension Blows out of Cylinder block

05 May 2015 10:26
#670764
Update - I pulled off the valve cover and discovered that the valve timing was way off - I screwed up somewhere and the chain must have jumped the sprockets. Anyway, I thought I might as well see if it would run so I reset the valve timing, installed the chain tensioner using longer bolts and she fired up immediately and settled in to a nice smooth idle. I certainly go lucky this time. Thank you to all that helped me out.
'72 Z1

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Re: Cam Chain Tension Blows out of Cylinder block

05 May 2015 12:49
#670777
Dodged a bullet. Good for you. :woohoo: I'd still Heli Coil them soon.
Steve

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