Cam Chain Tensioner Set Screw

[BeerMonger]

I'm rebuilding the cam chain tensioner as per bwringer's tutorial (link) on an '82 GS850G.

I'm stuck on step 2. After loosening the set screw nut, I cannot tighten the set screw at all. I can loosen it, then re-tighten but it does not go past the original position.

I think there are 3 possibilities:

1. The PO never released the rod by loosening the set screw. I suspect the cam chain would make a helluva racket and maybe even skip? I've only ridden this bike 1km around the block before starting my rebuild, and didn't hear anything crazy.

2. The PO didn't hold the set screw while tightening the set screw nut, and it tightened the set screw with it, thus locking the push rod in it's extended location. Would the bike run long like this?

3. The cam chain tensioner is a frankenstein inside.

My question: Am I safe to proceed with removal with the set screw tightened as sluggly as I can? What sort of mess will I have to deal with if the push rod doesn't 'hold' in place?

Thanks in advance.

[Tompasio]

Tight the set screw as tight a possible,Then remove the tensioner screws and remove it slowly,Nothting will happend.

[BeerMonger]

Okay, it did come out in one piece. Thanks.

[Steve]

It really does not matter too much whether the set screw is tight when you pull the tensioner out.

What matters most is how you put it back in. Retract the plunger, lock it in place with the set screw. Put the tensioner in place, maybe even rotate the crank a few degrees to make sure the front of the cam chain has all the tension, not the back. Release the set screw, watch for the knurled knob to turn as the tensioner takes up some slack. Turn the set screw until it's snug, then back off about 1/2 turn, lock it in place with the lock nut. Turn the crank a couple of turns to make sure everything is OK, put the ignition cover back on and ride.

.

[bwringer]

On about half the tensioners I encounter, some thumb-fingered past mechanic has mistakenly tightened the setscrew all the way.

Again, to be clear, in order for the tensioner to operate and automatically, adjust the pushrod must be free to move. This means the setscrew must be locked into position about half a turn out.

The good news is that it's usually not a big deal -- the cam chain and guides wear very slowly, so most bikes can go many thousands of miles with the tensioner mistakenly locked without an apparent problem.

On race engines, some people prefer a manual tensioner anyway.