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Help me diagnose a ticking noise? Video attached.

Cheburashka
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Posts: 122
Joined: Sun Feb 20, 2011 10:07 pm
Location: Moses Lake, WA

Post by Cheburashka » Thu Sep 06, 2012 8:07 pm

Well I guess the big question for me right now is, would you ride on it in this condition? I've been riding it around today and it seems OK, but I wonder if I'm doing more damage.

rzgkane
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Joined: Sun Feb 12, 2012 11:12 pm
Location: Huntington Beach, CA

Post by rzgkane » Thu Sep 06, 2012 8:10 pm

Cheburashka wrote:Well I guess the big question for me right now is, would you ride on it in this condition? I've been riding it around today and it seems OK, but I wonder if I'm doing more damage.
I wouldn't ride it around while it's making that sound. I'd be afraid of catastrophic damage in the event that whatever is loose finally lets go. To me, it sounds like one of the chains. Maybe even the oil filter chain.
1965 CA77Dream

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hondadreamca77
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Post by hondadreamca77 » Sat Sep 08, 2012 11:51 am

First guess is timing chain slack or valve lash......a loose valve guide can make noise as well but that's a remote possibility.

Cheburashka
honda305.com Member
Posts: 122
Joined: Sun Feb 20, 2011 10:07 pm
Location: Moses Lake, WA

I think maybe this has something to do with it.

Post by Cheburashka » Sat Sep 08, 2012 7:52 pm

Got it apart. Good tight cam chain, everything's clean, tight sprocket on cam, and some pretty major scuffing on one piston. The other is fine.

I'll have the bores measured, but the cylinder bore is scratched and probably will need to be redone.

Nice to know what was causing the trouble. Right where I was hearing the noise too!!
Attachments
DSC01177.JPG
Thinkin' it got a bit hot in there at one point.
Thinkin' it got a bit hot in there at one point.

rzgkane
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Posts: 537
Joined: Sun Feb 12, 2012 11:12 pm
Location: Huntington Beach, CA

Re: I think maybe this has something to do with it.

Post by rzgkane » Wed Sep 12, 2012 1:25 pm

Cheburashka wrote:Got it apart. Good tight cam chain, everything's clean, tight sprocket on cam, and some pretty major scuffing on one piston. The other is fine.

I'll have the bores measured, but the cylinder bore is scratched and probably will need to be redone.

Nice to know what was causing the trouble. Right where I was hearing the noise too!!
Really remedial question but what the heck... here goes. What causes a piston to become scuffed like that? Did the piston overheat and distort? Please educate me.
1965 CA77Dream

Cheburashka
honda305.com Member
Posts: 122
Joined: Sun Feb 20, 2011 10:07 pm
Location: Moses Lake, WA

Post by Cheburashka » Thu Sep 13, 2012 7:43 am

I've read on other sites that it's a lack of lubrication caused by fuel starvation, running lean and overheating. They were talking about dual-carb bikes and claiming that this kind of thing happens when a rider is moving at highway speeds and has to switch over to reserve and takes to long to get to the petcock. Apparently, it's always the carb with the shortest fuel line run which ends up going lean.

It sounds mildly plausible, although I'm not sure how much lubrication you get out of regular gasoline. Maybe on the "squish" stroke, but nowhere else.

I think in the end, the only thing that could cause this would be overheating.

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