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Discussion Starter · #1 ·
I'm having trouble tracking down a knocking/tapping noise with a new '85 Vulcan 700 project (Has 13,000 miles). I got a set of MCCT's, but they really didn't make a difference. (Maybe I'm doing something wrong with them) I'm not sure what to look for next. How common is it for lifters to stick if a bike sits for a while? Because that's what it sounds like to me. Anything else to try or other ideas?
Engine Sound Clip
 

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When you say you’re not sure if you did the MCCTs right, basically what you need to do is tighten them until the chain clack stops and then back them off a little to give yourself slack for expansion.
To be honest I can’t exactly tell if that’s what your sound is from the video. But here’s a clip of what the stock ACCT sounds like failing.

 

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Discussion Starter · #3 ·
When you say you’re not sure if you did the MCCTs right, basically what you need to do is tighten them until the chain clack stops and then back them off a little to give yourself slack for expansion.
To be honest I can’t exactly tell if that’s what your sound is from the video. But here’s a clip of what the stock ACCT sounds like failing.

I appreciate the quick response. When I tightened the MCCT's, the motor started bogging a little and the sound still didn't go away, so I backed the tensioner back out some.
 

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That does sound like valvetrain. Lifters can collapse and rockers can jump off the retainer clip. Valves can stick but it's not popping and missing, so I doubt it's that.

A stethoscope would probably pinpoint the sound at the top end, and lead you to the correct cylinder. Touch each valve cover, you might feel it.

The mcct adjustment is probably good.
 

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Discussion Starter · #5 ·
That does sound like valvetrain. Lifters can collapse and rockers can jump off the retainer clip. Valves can stick but it's not popping and missing, so I doubt it's that.

A stethoscope would probably pinpoint the sound at the top end, and lead you to the correct cylinder. Touch each valve cover, you might feel it.

The mcct adjustment is probably good.
Would any of those cause it to run weird? I bought it this way, so I have nothing to compare it to, but it seems to run/ride really well except for this sound.
 

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Yes and no, the 4 valve/cylinder can mask some, but it would run better without the extra slack in the valve lift.

That's a pretty substantial clack you have there.

Only one valve cover can be removed with the engine on the bike. I've never had to do it.
 

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Discussion Starter · #7 ·
Yes and no, the 4 valve/cylinder can mask some, but it would run better without the extra slack in the valve lift.

That's a pretty substantial clack you have there.

Only one valve cover can be removed with the engine on the bike. I've never had to do it.
I forgot to mention that it doesn't make the sound while it's cranking, just while running. I tried pulling the rear spark plug wires, and the sound went away. Could it be as simple as an exhaust leak?
 

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I forgot to mention that it doesn't make the sound while it's cranking, just while running. I tried pulling the rear spark plug wires, and the sound went away. Could it be as simple as an exhaust leak?
That's how you diagnose and pinpoint a rod knock. If the sound goes away when you kill the spark, a rod is knocking on that cylinder.

Have to say, the audio sounds a lot different on my PC. Not like valvetrain at all. The rythmic tap when you let off the gas is like a rod knock. On my phone I heard more rocker arm noise.

On a cold start, you can run your fingers around the leak points and feel for air. You have to work quick, a glove can be handy.

Look for sparkles in the oil.

 
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