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Cam chains, we don't need no stinking cam chains!

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Hotshoe
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Posts: 298
Joined: Tue Mar 30, 2010 12:51 pm
Location: Nawlins

Cam chains, we don't need no stinking cam chains!

Post by Hotshoe » Mon Aug 23, 2010 10:14 pm

Well, I found the source of the suspected cam chain rattle in my engine I posted about several weeks ago.
At that time I removed the cam chain tensioner and since it was OK, I decided to ride it easily and make it last till winter and pull the engine then.
A few days ago the engine suddenly died like I had turned the key off, no sounds of things breaking and the engine didn’t lock, it just died.
The engine kicked over freely but had no compression, when I pulled the points cover the rotor didn’t move when kicked over so …….
After some much appreciated guidance from Ed, I pulled my engine this evening and removed the top plate and sure enough, broken cam chain.
After removing the cam chain tensioner and looking down the cam chain tunnel at the lower cam chain roller that Ed suggested could be the problem, I could just make out that something wasn’t right down there.
I removed the oil pump and screen and lo and behold, two 10mm bolts and (thankfully) two cut washers, a quick look at the parts manual showed fasteners like that holding the lower roller in place.
No big surprise now but after pulling the head and cylinders I found the lower cam chain roller laying loose on the case, slightly chewed up but intact.
Apparently whoever was in this engine last forgot to tighten or improperly torqued the bolts and they vibrated out, fell down and found a new home nestled up against the oil pump screen leaving the roller and cam chain to rattle away till the chain finally failed.
Good news is that my first look at the valves and piston crowns this evening before I had to come in for supper didn’t reveal any contact damage so I may have lucked out there at least.
So, lesson learned - I shouldn’t have tried to make it last until winter making a noise like that but I have to hand it to Honda for designing an engine that can take that kind of abuse.
I’ll say 10 Hail Mary’s for I have sinned and start looking for parts.
Attachments
Can chain.jpg
Lower roller.jpg
Lower roller chewed up but mostly there at least.jpg
Thanks for small favors!.jpg

jensen
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Joined: Tue Feb 12, 2008 2:51 pm
Location: netherlands, huizen
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Post by jensen » Tue Aug 24, 2010 12:33 am

Hi,

You lucky ....... With this kind of treatment you deserved severe damage, but someone decided otherwise.

Btw, engine looks clean.

Jensen
assembly of Japanese motorcycles requires great peace of mind (Pirsig)

teazer
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Posts: 798
Joined: Mon Feb 08, 2010 10:32 pm
Location: Midwest US

Post by teazer » Tue Aug 24, 2010 9:49 pm

You , sir, are one lucky SOB. I had a couple of those rubber wheels break up and the heavy duty race quality cam chain stayed intact leading to bent valves and broken rocker arms.

Cam chains rarely break. You were lucky that your did.

BTW, that grooved chain wheel is past its Use By Date.

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