StarTrac NXT Chain Tensioning & Alignment Video

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!!

Badly worn chain and/or sprockets.

Chain tension incorrect - too loose.

Chain alignment wrong. Careless chain adjustment can result in the chain/rear sprocket (rear wheel) alignment to be out. The rear wheel and the chain centre lines should be exactly parallel.

These are the instructions for adjusting the chain. They are taken directly from the manual available at http://ep.yimg.com/ty/cdn/razorama/e100e200e300manual.pdf

To adjust the chain:
1. Loosen the axle
2. Loosen the brake anchor (this is attached with the small bolt in the long slot on the left side of the rear fork)
3. Tighten the tension adjusters on the axle 1/8 to 1/4 turn to tension the chain. Tighten both adjusters the exact same amount to maintain the wheel alignment.
Note: this system of adjusters is common to motorcycles and BMX
bicycles so I your are not familiar with it, if you know anyone who is,
they would not have a problem adjusting it for you.
Chain tension: The chain should be "just not-quite snug" in other
words, not taut or sloppy loose. BE CAREFUL NOT TO ADJUST TOO TIGHT. The tensioning system can easily impart too much tension and snap the chain or bend the motor output shaft. Turn the adjusters 1/8 to 1/4 turn at a time and recheck the tension each time.
4. Once the tension is good, tighten the axle and brake anchor bolt. Test run the scooter. Readjust as needed.

steps to loosen the chain on a CBF600:
-check the chain tension while the bike is sitting on the kickstand in neutral. It should have 1" to 1.5" FREEplay when measuring halfway between the front and rear sprocket.
-loosen the rear axe nut approx 1 full turn, this should require a 27mm socket.
-look for adjusting bolts on either side of the swingarm, sticking out from the rear plate. There will be an adjusting nut and lock nut on it.
- Loosen the 10mm locknuts on both sides (bringing it towards the rear of the bike) while holding the head of the 12mm adjusting nut from turning.
- Adjust both of the adjusting nuts outwards to loosen the chain, inwards to tighten the chain. 1/2 turn on the adjusting bolt will change the chain freeplay by about 10mm.
- Hold the 12mm nut, and snug the 10mm nut up to it. This will lock the adjusters in place.
- While holding the bike, press firmly on the back of the rear tire, This will move the rear wheel forward, and taking up any slack that was created by loosening the adjusting nuts.
- (Optional step but suggested) Use the hatch marks on the swingarm, just below the axle, to gauge whether the rear axle is adjusted evenly on both sides. Make any adjustments necessary to align the axle evenly on both sides. This will require moving the adjuster on one side ONLY. Consider your chain tension while doing this step (if necessary) since you can either loosen one side or tighten the other. After making any adjustments, press the wheel forward again and re-check your alignment.
- Using a 27mm socket, tighten the axle to the proper torque, which should be around 85 Ft.Lbs. If you are not sure about whether or not the axle nut was properly tightened, be sure to ride the bike carefully to a motorcycle shop and ask them to double check it.
-Finally, check the chain tension and make any adjustments necessary by following the previous steps.

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