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Discussion Starter · #1 · (Edited)
You won't have to wonder if you are hearing things if it is the cam chain. It is very distinct and not quiet by any means. During the cooler months it 's down right embarrassing to be pulled up along side someone while thinking "Yep this is a sharp looking bike" only to have the thought drowned out by the ticking of the engine. It really sounds like a rod or lifter ticking. And you wonder when the rod is going to stick its ugly head out through the cylinder wall. Hoot

Well, this is a subject worth a lot of attention. First, if your ACCT is not doing its job and you are getting a lot of noise coming from your cam chain, it is because of two things: One, your ACCT spring has lost its strength to keep tension on the cam chain. The fix for this is to replace the spring.
Two, the ACCT has become stuck and does not keep tension on the cam chain. In this case try Grambo's trick to free up the ACCT. There is no way to increase the tension on the ACCT without removing it, so Grambo's trick is not an adjustment, it is simply a fix for a stuck tensioner.

Our VN750 has Automatic Cam Chain Tensioners (ACCT) that have weak springs in them. The tensioner is a basic design, The main parts is a spring, slotted screw and a threaded plunger.

How it works is, one end of the spring goes in the slotted screw and the other end of the spring goes into a groove in the tensioner housing. The spring is preloaded by turning the screw clockwise 4-5 times. The plunger is then screwed on a couple threads then held in place by a retainer. The spring is now constantly trying to unscrew (turn CCW) the slotted screw out of the plunger. This in turn keeps the plunger always wanting to be extended. This is what makes the tensioner give constant pressure on the cam chain automatically.

The plunger has a mushroomed end which presses on the assembly inside the engine which goes in contact with the cam chain itself. You can see now that if the spring is weak the pressure the tensioner gives the cam chain will also be weak. NOTE: The plunger will not retract simply by pushing in on it. You will need to turn the screw CW at the same time. This is good because the cam chain can't push it in either. If it could it would be a shock absorber instead of a tensioner. This is good to know when you are installing the tensioner back in the engine.

When the tensioner no longer can keep the cam chain at the proper tension the cam chain becomes loose. You will notice several problems with your engine when this begins to happen. Most of the noise you hear may only appear when the engine is cold but it may go away once the engine warms up. It will be a chain stapping sound from one of your cylinders. Because a loose chain will affect your valve train timing you may also hear an engine knock. It's as if you have bad gas. Another problem my bike had when this happened to me was I would get raw gas coming out of that cylinders exhaust. I know now that my exhaust valve must been opening during compression because the valves timing was off. The cause of your tensioner to stop working as designed can either be because the tensioner is stuck in a loose position or the spring no longer has the proper tension.
 
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