Chain How often do I need to check the chain’s tension? How?

hey Dominico,
This is the way PROFESSIONAL mechanics do a chain/sprocket check and drive chain alignment and tension.. Proper chain tension is very important to the life of your chain and sprockets and performance of your bike. First, you need to check to see if the chain/sprockets need replacing. (Chain and sprockets are ALWAYS replaced as a set (-all-3)..if you replace a chain on worn sprockets.. the chain will stretch out QUICK.. and if you put new sprockets with a worn chain.. the sprockets will be worn out QUICK too!!) ...To do this..the bike needs to be on the center stand or bike stand...NOT on the side stand...
...now...--remove the chain guard-- next..Sprocket check time - take one hand and squeeze the chain (grab the chain above and below the swingarm) at the point between the axle and the swingarm bolt.. as hard as possible. to take all the slack out of the chain and put the tension completely around the back sprocket.. while you are squeezing the chain as hard and tight as possible.. - with your other hand - try to lift/pull the chain off the rear sprocket.. IF you can pull the chain off enough to see if there is a .200" or 5mm max. gap between the chain and sprocket - under the chain... or MORE THAN A HALF a tooth groove under the chain..or the chain pulls up more than two teeth...OR the teeth on either sprocket are "pointed thin" or rounded inside....you need to replace the chain/sprockets.
...ONCE you are sure the chain/sprockets are good..its time to CORRECTLY align and adjust the chain tension. Loosen the axle nut.. DO NOT remove it.. now - tap it gently to make sure its loose...loose the chain adjuster nuts.. back them off a good bit, but do not remove them...you may,also need to loose the rear brake caliper mounts ..you should be able to move the rear wheel forward and backward with your hand.(this is to assure you have sufficient "looseness" to make the proper adjustment...NOW - pull the rear tire backwards until it stops.. - run the adjuster nut(s) until they are just snug..ALIGNMENT - This is CRITICAL - (did you remove the chain guard yet?) - do that now. You must be able to see down the entire length of the chain (above the swingarm)..The chain MUST RUN IN A STRAIGHT LINE!! .. The little marks on the swingarm are just "guides".. never use them as perfect.. the only way to assure CORRECT ALIGNMENT is a visual check of the chain to make sure its in a straight line!!!! - ...ANY bend, crook, or mis-alignment will cause premature wear and tear, and make it harder for your engine to make it turn. - Now - Rotate the wheel and find the tightest point of the chain... there is one, and its normal... LEAVE the tight point located between the two sprockets on the top of the swingarm. This is where you will "feel" for the correct tension.
The biggest thing most people miss when adjusting the tension is having the AXEL/NUT and the SWINGARM PIVOT SHAFT and the COUNTERSHAFT C/L (front sprocket shaft) IN A STRAIGHT LINE - ALL THREE ARE ON THE SAME PLANE!!!!!
. NOW, You may have to get a buddy to help pull the swing arm up.. (I use a tie down strap through the rear wheel and over the seat pulled tight enough to make AND KEEP the STRAIGHT LINE!!)
..Once you have established the straight line - --- - --- - and MADE SURE the chain is RUNNING STRAIGHT on both sprockets.. NOW _ its time to adjust the tension. There WILL be a tightest and loosest point of the chain..(normal).. you MUST adjust the tension using the TIGHTEST point of the chain....set the tension so you can move the chain up and down (total movement) about 1 3/8 inch to a max of 2 inches!! Once you have established the chain is straight and the tension is correct, its time to TIGHTEN EVERYTHING in order... start with snugging the axle nut.. then snug the adjuster nuts more..-- DOUBLE CHECK you chain alignment.. now - tighten the axle - TIGHT!!... tighten the adjuster nuts..lock down the lock nuts.. tighten the caliper.. TRIPLE CHECK the alignment... double check the tension...double check all the nuts... install the chain guard... REMOVE whatever you use the keep the straight line straight..

TRIPLE CHECK ALL NUTS!!! NOW ROTATE THE REAR WHEEL AND CHECK FOR BINDING AND MAKE SURE THE CHAIN IS WORKING CORRECTLY AND NOT TOO LOOSE..
KNOW you have done a job correctly!! (I am a factory trained mechanic, race engine builder, port work guy, race tuner.)..
GREAT JOB!!

Pull the side cover and check for a broken or misaligned chain tensioner. I assume that you have loosened the bar nut on the side cover before attempting to adjust the chain tension. The methiod varies depending on whether your model has the side chain tensioner or the quick chain tensioner.

Check that the chain brake is in disengaged position by
moving the front hand guard towards the front handle.
Remove the bar nuts and remove the clutch cover (chain
brake). Take off the transportation ring.
Fit the bar over the bar bolts. Place the bar in its rearmost
position. Place the chain over the drive sprocket locate it in
the groove on the bar. Begin on the top edge of the bar.

Make sure that the edges of the cutting links are facing
forward on the top edge of the bar.
Fit the clutch cover (chain brake) and locate the chain
adjuster pin in the cut-out in the bar. Check that the drive
links of the chain fit correctly on the drive sprocket and that
the chain is in the groove on the bar. Tighten the bar nuts
finger-tight.
Tension the chain by turning the chain tensioning screw
clockwise using the combination spanner. The chain
should be tensioned until it does not sag from the
underside of the bar.
The chain is correctly tensioned when it does not sag from
the underside of the bar, but can still be turned easily by
hand. Hold up the bar tip and tighten the bar nuts with the
combination spanner.
When fitting a new chain, the chain tension has to be
checked frequently until the chain is run-in. Check the
chain tension regularly. A correctly tensioned chain
ensures good cutting performance and long life.

Your manual can be found here:

http://www.blackanddecker.com/Manuals.aspx with pop-ups enabled then enter your model number
or
http://www.dewaltservicenet.com/documents/English/Instruction%20Manual/90560838,CCS818.pdf

See the instructions for replacing the chain on page 11. It makes reference to the figures on page 6 so that you know exactly what to remove.

Basically... loosen the bar allen screws. Remove the sprocket cover. Loosen the bar retaining bolts. Use a flat bladed screwdriver on the bar / chain tension screw to shorten the bar enough to install the chain. Then adjust the chain tensioner so that there is just a little slack in the chain at the bottom of bar between the drive sprocket and the bar. Tighten the bar retaining bolts install the cover / tighten all cover fasteners. (see details D and E page 6 of the 2nd link above.)

The steps below are copied from the manual.... I can not undo the formatting and can not post the figures here due to size restrictions..

Thanks for choosing FixYa,
Kelly

Replacing the Saw Chain

CAUTION: Sharp chain. Always wear protective gloves when

handling the chain. The chain is sharp and can cut you when it is

not running.

WARNING: Sharp moving chain. To prevent accidental

operation, insure that battery is disconnected from the tool

before performing the following operations. Failure to do this

could result in serious personal injury.

• Place the saw on a firm surface. Rotate the two allen head screws

(11) counterclockwise with the wrench (13) provided as shown in

figure E.

• To remove the saw chain (9), rotate the tension adjustment screw

(23) in the front of the housing using the flat screwdriver end of the

wrench (13) as shown in figure F. Turning the screw

counterclockwise allows the guide bar to recede and reduces the

tension on the chain so that it may be removed.

• Remove sprocket cover (10) and allen head screws (11).

• Lift the worn saw chain (9) out of the groove in the guide bar (8).

• Place new chain in groove of guide bar making sure saw teeth are

facing correct direction by matching arrow on chain with graphic on

housing shown in figure G.

• Place the saw chain and guide bar assembly around the sprocket

(19). Check to make sure that the slot (20) in the guide bar (8) is

over the two location pins (21) shown in figure E and that the hole

below the slot is located over the adjustment pin (22).

• Replace sprocket cover (10) and thread allen head screws (11) in

with wrench until snug, then back wrench off one full turn.

• Pull bar nose up and keep it up as you adjust tension.

• Rotate the tension adjustment screw (23) in the front of the housing

clockwise to increase the chain tension as in Figure F.

• Follow instructions in "Adjusting Chain Tension" section.

• While still holding the bar nose up, securely tighten the rear allen

screw (11) first, then tighten the front allen screw.

• When the chain is new check the tension frequently (after

disconnecting battery) during the first 2 hours of use as a new chain

stretches slightly.

Adjusting Chain Tension

CAUTION: Sharp chain. Always wear protective gloves when

handling the chain. The chain is sharp and can cut you when it is

not running.

WARNING: Sharp moving chain. To prevent accidental

operation, insure that battery is disconnected from the tool

before performing the following operations. Failure to do this

could result in serious personal injury.

• With the saw still on a firm surface check the chain tension. The
tension is correct when the chain snaps back after being pulled

1/8 inch (3mm) away from the guide bar (8) with light force from the

middle finger and thumb as shown in figure H. There should be no

"sag" between the guide bar and the chain on the underside as

shown in figure I.

• To adjust saw chain tension, loosen the allen head screws (11).

• Rotate the tension adjustment screw (23) in the front of the housing

using the flat screwdriver end of the wrench (13) as shown in

figure F.

• Do not over-tension the chain as this will lead to excessive wear

and will reduce the life of the bar and chain. Overtensioning also

reduces the amount of cuts you will get per battery charge.

• Once chain tension is correct, tighten allen head screws (11).

• When the chain is new check the tension frequently (after

disconnecting battery) during the first 2 hours of use as a new chain
stretches slightly.

Get the rear wheel off the ground and adjust the chain tension. When checking the tension spin the rear wheel and check that the tension does not go slack or get tighter. If the chain is riding up and down the sprocket teeth then the chain is stretched and needs to be replaced. This is the grinding/clunking noise you are hearing. If the sprockets are worn consider a chain and sprocket set, it can be a less expensive option than buying the parts separately.

1998-2003 To Remove:

1. Remove or disconnect the following:
   • Crankshaft pulley and hub
   • Drive belt tensioner
     
     
   • Timing chain cover bolts
     
     
   • Timing chain cover and gasket
2. Install a bolt in the end of the crankshaft CAUTION
   Do not install the crankshaft balancer bolt or a bolt longer than 1 inch or damage to the crankshaft threaded hole will result.
   
3. Rotate crankshaft until the number 1 piston is at Top Dead Center of compression stroke.
4. Make sure that the alignment marks are aligned with the tabs on the timing chain tensioner.
   
   
5. Measure distance between hole in bracket and unworn surface of timing chain tensioner shoe. NOTE: If distance between the hole and unworn surface of timing chain tensioner is greater than 0.314 in (8 mm), replace tensioner, timing chain and sprockets.
   
6. Remove timing chain tensioner bolts.
7. Remove the timing chain, timing chain tensioner and camshaft sprocket at the same time.
8. Remove the crankshaft sprocket using special tool J 22888-20A or equivalent.
9. Remove crankshaft sprocket alignment key.

NOTE: If any camshaft components are being replaced to correct a noise problem, all camshaft drive components must be replaced.
To Install:

1. Install the crankshaft sprocket alignment key.
2. Install the crankshaft sprocket using special tool J 5590 or equivalent.
   
   
3. Compress the timing chain tensioner spring and insert a pin into the tensioner hole to retain the tensioner shoe.
4. Install timing chain and timing chain tensioner (do not tighten tension bolts).
5. Align the crankshaft and camshaft timing marks with the tab on the timing chain tensioner.
6. Tighten the timing chain tensioner bolts.
   • Torque to: 18 ft lbs (24 Nm)
7. Tighten the camshaft sprocket bolt.
   • Torque to: 96 ft lbs (130 Nm)
8. Remove pin from timing chain tensioner hole.
9. Remove bolt from end of crankshaft. CAUTION
   Inspect the timing chain cover for warping or damage. Replace if needed.
   
10. Clean all timing chain cover mating surfaces.
11. Install or connect the following:
    • Timing chain cover to the engine block
      1. Ensure that the gasket is installed properly in the groove in the timing chain cover
    • Timing chain cover and make sure it fully seated on the alignment dowel pins
    • Timing chain cover bolts
      1. Torque to: 97 inch lbs (11 Nm)
    • Drive belt tensioner
    • Crankshaft damper hub and the crankshaft pulley

The chain usually comes off because it is not tight enough or the chain is not aligned correctly with the sprockets. Check the chain tensioner to see if it is keeping the chain tight and not moving even though it is tight, if it loosens, replace the tensioner. Check the chain for any broken or worn spots or links, if any are found replace the chain.

Depending on the model, you adjust the chain tension using the screw that is located either between or below the two nuts that hold the sprocket/bar/chain cover. Loosen the nuts and turn the screw clockwise to tighten, counter-clockwise to loosen. Once you have the tension set, lift up on the bar from underneath and tighten the two nuts. Proper tension should show about half of the chain drive, and should only be done when cold. After 4 to 5 minutes of run time, stop the saw and check the tension again. A little heat in the bar/chain will cause it to loosen up. It will need re-adjusting.

Ok to get correct tension on chain, basically loosen it a little until the chain on the underside of the bar is hanging a little... Now start tightening it up again. Basically you want the chain (the main part of each link) to be just touching the the underside of the bar. This will give correct tension... Note that chain does expand as it heats up so it may loose tension... so this is perhaps best done when the saw and chain has warmed a little. Also, new chain will stretch a little naturally so check tension each tme you use the saw.

If you do not know hoe to sharpen a chain properly, it is best to get someone else to sharpen it, or buy a new chain... Eventually all chains will need to be replaced because they can only be sharpened so many times before the cutting teeth become too small to work effectively or safely.

As for oil, if it is an electric chain saw, you only need chain/bar oil. Any good name branded bar/chain oil designed for chainsaws will work well.

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Thanks.