Author Topic: can a CB Jump a link in the timing chain?  (Read 1244 times)

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Offline Flying J

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can a CB Jump a link in the timing chain?
« on: July 14, 2009, 03:03:12 PM »
There is a bike im looking at and here is what the ad says "Honda CB450. It does not run. My best guess is that the timing chain jumped a link." Is that possible? and if it did will it cause the valves to hit the pistons making the engine junk? Im trying to figure out what to offer this guy.

Offline Alan F.

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Re: can a CB Jump a link in the timing chain?
« Reply #1 on: July 14, 2009, 03:09:46 PM »
Yeah I think with poor enough tension the camchain could literally slip a link, damage is possible, but that question is best for a 450 guru.

Offline Jay B

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Re: can a CB Jump a link in the timing chain?
« Reply #2 on: July 15, 2009, 06:24:35 AM »
I don't have experiance with a 450, but I wouldn't think so. If the chain was loose enough to slip a tooth it would be thrashing around in there big time.
Jay
'77 CB550K
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2001 Road King
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Offline bryanj

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Re: can a CB Jump a link in the timing chain?
« Reply #3 on: July 15, 2009, 07:29:00 AM »
That chain is incredibly long and i think it can jump. Usualy it just falls apart where it wasnt linked properly when fitted.
Either way you will have bent valves 90% of the time
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

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Offline tbpmusic

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Re: can a CB Jump a link in the timing chain?
« Reply #4 on: July 15, 2009, 07:51:14 AM »
There is a bike im looking at and here is what the ad says "Honda CB450. It does not run. My best guess is that the timing chain jumped a link." Is that possible? and if it did will it cause the valves to hit the pistons making the engine junk? Im trying to figure out what to offer this guy.

Assuming you're talking about the old DOHC 450, and not the '80's model "Hawks" (of which I know very little) -

It is possible for the cam chain to "jump teeth" (usually becuase the tensioner isn't properly set, or is damaged) - doesn't happen all that often, as it would make quite an alarming racket as it approached that point, and scare most folks into shutting it down.

Also possible that if it does happen, valves could get bent - though it would have to jump more than one tooth for that. But jumping just a small amount would definitely cause it to not run.

However, valves can be replaced, so can all the rest of the top end parts.

A non-running titled 450 with potentially major engine problems - I might offer a few hundred bucks, depending on overall condition.
"If you can't fix it with a hammer, then it's an electrical problem"

Bill Lane
 '71 CB450 Mutant/ '75 CB200/ '81 CM200/ '71 C70M