Cam chain adjustment question

[SD_GS500E]

I recently picked up a manual cam chain tensioner, and in the installation instructions it says to verify that the cam chain has 1/4-3/8" deflection between the two cams, but they also emphasize several times, "DO NOT OVERTIGHTEN!" 

So just to be sure, you measure deflection from as far down as the chain will go to as high as it will go, correct (just like the drive chain)?  So the total change from when the chain is pulled up /\ to when the chain is pulled down \/ should be 1/4-3/8", or or is deflection measured from its point at rest to either up or down so that total slack is 1/2-3/4"?

I installed it with about 3/8-1/2" from /\ to \/, fired it up and it sounded nicer, and the engine turned over much smoother (freakin' tick is still there though), but I've been too scared to ride it until I can verify I didn't over tighten it.

[fetor56]

Drive chain slack is measured from it's approx centre(chain at rest) to how high the bottom of the chain will move upwards,book sayes 20-30mm.I would think a cam chain is the same,but this needs to be confirmed.

[twinrat]

why didnt you use the standard cam chain tensioner.as only have to retract the plunger with a screw driver ,offer tensioner up to the block ,tighten cap screws and remove screw driver.

[Joolstacho]

"Freakin' tick" -Mate, remember it IS an air cooled four stroke... if you didn't have some 'tick' up there you'd be losing compression - the valves wouldn't be seating fully.
Mind you, your tick could be something else... 

[SD_GS500E]

why didnt you use the standard cam chain tensioner.as only have to retract the plunger with a screw driver ,offer tensioner up to the block ,tighten cap screws and remove screw driver.

Because I'm a tinkerer for the most part.  But I have to say, after putting it on, the bikes sounds so much better that it makes me want to keep it.

As for the tick, well, that's only concerning because I recently developed a vibration in the foot pedal at about 7k rpm which urged me to do a valve shim adjustment, after which I noticed this tick I'd never noticed.  After verifying my gap more times than I can remember and looking through thread after thread and watching all sorts of different video on youtube, a faulty cam chain tensioner looked like my issue, so I figured I'd try.  I got a manual because I can adjust it my self, it's a simple design with little chance of mechanical failure (unless overtightened), and it takes the mystery out of whether or not the tensioner was or wasn't the issue rather than just keep asking people on the web what my problem was.  Well the new tensioner appear to make the engine sound better, but I won't know if that was the vibration until I take it out....probably gonna crack the cover off one more time and try to fine tune it a bit.  I initially had it at 5/16" upward slack, but when I tightened the jam bolt it tightened up just a hair.

[twinrat]

I wouldn't worry about a tick ,i set my valve clearence's at 4 to 4.5 thou it ticks away at idle and is not noticable while riding  ,i will not look at my valve shims again for 40,000 miles or bike goes off tune then i will suspect them.Your timing chain is small in size and is probably best to be set correctly .I cant help thinking that you have made yourself a lot of unecessary work and worry everytime you think your chain  may need adjustment ,the auto tensioner on these is well proven and reliable.l

[SD_GS500E]

I wouldn't worry about a tick ,i set my valve clearence's at 4 to 4.5 thou it ticks away at idle and is not noticable while riding  ,i will not look at my valve shims again for 40,000 miles or bike goes off tune then i will suspect them.Your timing chain is small in size and is probably best to be set correctly .I cant help thinking that you have made yourself a lot of unecessary work and worry everytime you think your chain  may need adjustment ,the auto tensioner on these is well proven and reliable.l

I hear ya.  A lot of folks in the Jeep community are the same way, but I pull that apart and inspect and adjust after almost every wheeling session.  As is, the oil gets changed every 2500 miles, at the same time, basically a full tune up is done.  Bike will be the same way.  I don't have to pay for labor, and it's a reason to get away from the little lady and drink some beer in the privacy of my own garage ta boot.

And yeah, maybe it's over kill, but then again, I beat the living poop out of my Jeep and it still purrs like a kitten with 187,000 miles on it.  And being that it now takes me about 30 min to pull the bike apart, check the valves, and put it back together, it just doesn't strike me as a lot of work.

Now pulling the AW4 tranny out of the Jeep by myself...that was a b!tch...that took 3 days to get out, repair and get back in.   By comparison, adjusting a timing chain is nothing. =)

[SD_GS500E]

Ok, so after rereading instructions and rewatching http://www.youtube.com/watch?v=EBFB_RyOqEo I realized the total slack from top to bottom should be 1/4-3/16", not from centerline.  I should have put 2 and 2 together, but the instructions tell you tighten while pushing down on the chain, then measure deflection...the video shows total movement "from top to bottom" should be 1/4".

Anywho, readjusted it, took it for a ride....wholly rat poop!  what a difference!  The sound is gone, the vibe is extremely diminished, power is increased, response is better, acceleration is better, and oddly enough, I get higher speed at lower rpm now....that I can't figure out why.  But I used to hit about 7k rpm at 80mph, had to get it up to over 90 today to find the vibe.

Vibe is still there though....

All I can say is, if the auto tensioner is usually good on these, then mine must have been butt buggered by B.A. Baracus.

[Badot]

I get higher speed at lower rpm now....that I can't figure out why.  But I used to hit about 7k rpm at 80mph, had to get it up to over 90 today to find the vibe.

The tach is driven by the exhaust cam, so with a loose chain it could easily flop around and mess with the reading.

[twinrat]

vibration will occur somewhere in the rev range even tho you have a balancer shaft to help iron out the vibe's its the nature of vertical twin design .  Even horizontaly opposed twins will do it somwhere in there rev range.Design engineers try to give there best guess at where these engines will be running most of the time and set the balance at a certain point say between 8500 to 11000 rpm   where they will rarly be run regulary ,in saying that there  are those who may run at these revs and find they leave a trail of parts behind them .

[Joolstacho]

And I've just got to add... Just don't let your tensioner get old and tired. PO of my bike had just let it go too far... it failed (stuffed spring)... timing chain loosened off and jumped camshaft teeth... valves hit pistons and bent. Cost of a new tensioner would have been around $90, cost of (parts only) for the top end rebuild $380.
Don't take no rocket scientist to work out what should've happened there!