CBR600F3-4i/CBR900CB900 Manual Cam Chain Tensioner

 

Installing the new manual cam chain tensioner:

 

1.        You will need a pair of wrenches to fit the lock nut and acorn nut, a 4mm hex key (allen head) wrench or socket, ratchet, inch/lb torque wrench, gasket sealer, some blue hand tool thread lock compound, and an appropriate size socket/ratchet to turn over the engine.

2.        Remove whatever parts are necessary to get to the cam chain tensioner on the right side of the engine..

3.        Remove the “automatic” tensioner body from the motor by removing the two small bolts. 

4.        On the new tensioner back the adjustment bolt out a fair amount and remove the plastic sleeves from the mount bolts

5.        Put some Yamabond (Hondabond, Kawabond – whatever bond) sealant or a similar goop on the tensioner gasket.  I don’t know for sure, but even grease may work fine.

6.        If you like, apply some blue hand tool thread locking compound on the supplied countersunk bolts then install the tensioner in place.  NOTE:  Install the tensioner in the proper direction, the adjuster is offset to one side.

7.        Torque the bolts to 72 in/lb (6 ft/lb or 8 N/m per http://www.machinetoolhelp.com/Repairing/bolt-torque-chart.html ) if you wish, I just used a 4 mm allen wrench and my “torque wrench arm”… if you know what I mean.

8.        Turn the adjuster bolt in as far as possible by hand.

9.        Remove either the left or right engine case side cover, which ever is easier (probably right side). 

10.     Using the appropriate socket and ratchet on the bolt in the end of the crank shaft,

a.        From the right side, rotate the crank shaft slowly clockwise, from the left side rotate the crank shaft slowly counterclockwise which will pull the cam chain taut on the drive side making the tensioner side slack, while turning the tensioner adjustment screw by hand.  DO NOT spin the motor over with the starter, you risk jumping cam timing or possible valve damage due to excess chain slack.  Do not force the crank if it should hit something hard, you do NOT want to damage a valve.

b.       Turn the motor over for a few revolutions with the ratchet while turning the adjuster bolt by hand, the tensioner bolt will turn in easily when taking up slack in the chain, but will resist turning when either the chain is under tension (turning the crank the wrong way) or when the slack has been taken up. 

c.        You should be able to tell when the slack is gone, the bolt will no longer turn easily. 

d.       Back off 1/6 turn (one flat of the acorn nut).

e.        Using one wrench snug the tensioner locking nut down tight while holding the acorn nut with the other wrench.

f.         Rotate the crank slowly over again by hand to make sure valves are not out of time and hitting the pistons.

11.     Start the engine and warm it up to operating temperature.

12.     With the engine running, listen for any chain noise.  If you hear any chain noise:

a.        Loosen the lock nut and turn the tensioner bolt in slightly and slowly until rattle is gone.  This step is really hard with the tight space on some bikes.

b.       Tighten the locking nut while holding the tensioner nut in place with a wrench to keep it from turning.

 

This works without gimmicks and guesswork that can over tighten the chains or let them flail around in the cases.  Re-adjust every several thousand miles or if you hear the rattle of cam chains again.  I think I’ve only done about 4 adjustments over the past 25,000 miles using the “sound” method on the KLX.  I didn’t need any change in adjustment on the Zephyr after installation.  The key point is what the tensioner does – it simply takes up excess slack so the chain(s) don’t slap around and wear prematurely.  There is no preloading necessary.