:: Yamaha Virago XV Forums That Rock!!! XV700 Knocking, Tapping In Top Of Front Cylinder (SOLVED)

#1:  Knocking, Tapping In Top Of Front Cylinder (SOLVED) Author: 1986 XV700 Post Posted: Sat Aug 28, 2010 1:06 am

This post started out as a question until I decided to check my valve clearance "just one more time." I'll go ahead and tell you the problem wasn't valves, rocker arms or cam.

My bike decided to join the front cylinder knocking club yesterday morning on my way to work. For the past year or so its had a persistent light tapping sound that would occasionally get loud on deceleration but usually what might be better described as a tick. This evening I decided to figure out what the problem was since it was now embarrassingly loud and really had me concerned.

I checked all the normal things one would check:
Oil Level - Good.
Valve Clearance - It was out pretty bad but proved not to be the problem after I corrected it.
Rocker Arm Play - There was a little side to side movement on the shaft but there wasn't any movement to make me think the pivot hole was worn.
Oil Flow/Pressure - Cranked up the bike with the front intake valve cover off and oil splatter everywhere and puddled on the floor.

When I cranked the bike with the valve covers off I also had the cam cover off. I looked in at the rotating cam end and noticed the chain slapping the cylinder head in rhythm with the tapping sound. Now it was clear the chain tensioner must have a problem right? It did, would you like to see it? Before you look I'll tell you what I found and how I fixed it.

The problem was one end of the clock spring was no longer connected to the tensioner housing and therefore couldn't apply proper tension to the tension pin. From what I could tell the fixed end of the spring was supposed to be in a hole that is partially drilled in the side of the spring cavity. I heated the fixed end of the spring and formed a hook in it that would fit into the cavity. Because I wanted it to stay put I wedged it into the hole with the hollow aluminum portion of a 1/8" pop rivet. The rivet isn't "set" just gently tapped in to keep the spring in place.

Before winding the spring into place I twisted the tension adjustment pin to the left tightly to keep it in place and hold the tension pin fully extended. I was then able to twist the tensioner housing, winding the spring into the cavity. Once wound into the cavity I put three additional twists on the spring to supply tension to the pin while extended. The cap was bolted back into place and I retracted the tension pin by twisting the adjustment pin tightly to the right so it would stay put. After installing the tensioner back into the engine a slight left twist on the adjustment pin and I heard it zip back into place.

I restarted the bike with the cam cover still off and it actually sounded better than a sewing machine. A sewing machine ticks, my bike don't. Yeah baby, the sweet sound of success!

Here's a few pictures of the disassembled tensioner: XV700 Knocking, Tapping In Top Of Front Cylinder (SOLVED)

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