How to adjust chain and rear wheel alignment

[Fastprof]

Part 1

I thought the group might find a How To on chain adjustment helpful since there are a few new riders in this forum. Doing your own basic maintenance is a good idea as it helps you learn about your bike, adds to the riding experience and helps you ensure your bike is adjusted for safe/optimal performance. While you don't need a rear stand, it saves time and effort in addition to safely holding the bike upright while you spin the rear tire. Keep your fingers well clear of the chain and the rear sprocket. While it does not seem that a wheel spinning this slowly can do damage, there is enough inertia and mass in that rear wheel to crush or sever fingers( I jest not folks).

Necessary tools would be a 22mm socket with a power bar to loosen the rear axel nut (a torque wrench to tighten it is best, but this is optional), a 12mm socket and a 12mm wrench (two 12mm wrenches will work too), and an accurate tape measure or steel ruler.
Step 1, Finding the tightest part of the chain. Place your bike on the rear stand if you have one. With a tape measure pick a spot on the bottom of the swing arm and measure to the top of the chain. Slowly spin the rear wheel and watch for the smallest distance between the top of the chain and the swing arm (it may only be 1/16 " or less). This is the tightest part of the chain and is the best place to check your chain slack. If you do not have a rear stand, it might be easier to measure if you have a helper to roll the bike forward until you get the tightest spot on the chain. Again, watch your fingers around the chain and sprocket.


Step 2, Check the chain slack. A little bit ahead of the midway point on the swing arm is the midpoint of the chain. This is where you want to take your measurement. You want to pull up on the bottom run of the chain as far as it goes with about 10 lbs of force. Place the end of your tape measure at the center point of the chain rivets (I prefer to rest my arm on the foot peg and start at the 1" mark to ensure a more accurate measurement).


While holding your tape measure as still as possible, pull down on the chain and note the point on the tape where the center of the rivets align. You might find the tape measure has moved during this process, so feel free you check this measurement several times. Tip: if you start your measurement at the 1" mark on the tape measure, don't forget to subtract that 1" from your total measurement otherwise you will end up with an extra inch of slack (for example, the pic below looks like I have 3" of slack when I only have 2").



The spec. for a FZ6R chain is 1.77 - 2.17 inches or 45 mm - 55mm of slack. Vernier Callipers, if you have them, are handy for measuring in decimals. If the center rivets of your chain move up and down 1 7/8 " to 2 1/8", you do not have to adjust your chain at this time. If your chain moves more or less than the previous spec., then you should adjust your chain.

Running a chain that is too loose causes the chain to flail around the sprockets that makes them at best noisy, and at worst in danger of slipping on or off the sprocket. Running a chain that is too tight places strain on the transmission, can cause performance loss from excess friction, and can wear your chain and sprockets much faster. Worst case scenario for an out of spec. chain is that the chain breaks/comes off the sprockets and jams the rear wheel throwing you on your backside, or jams the front sprocket causing your engine and transmission to grind to a sudden stop causing beaucoup damage to the engine internals. It is always preferable to run your chain on the loose end of the 2 1/8" slack which is still safe, but will minimize friction and wear. If your chain needs adjustment, see part 2 in the next post.

[Fastprof]

Part 2

Step 3, Adjusting the chain. With the 22mm socket and power bar, loosen the axel nut. Careful not to knock the bike off of the side stand by pulling forward on the power bar. Pull upwards instead. Do not remove the nut.

• Tip # 1, always pull on a wrench never push. Pushing results in less force and more effort, and if the wrench slips or the nut releases suddenly, you are going to have skinned knuckles.
• Tip #2, lefty = loosie; righty = tightie.
• Tip #3, if you do not have a power bar you can slip a bit of steel pipe over your ratchet wrench to gain more leverage (use caution here as the pipe can slip and more than a few ratchets have been destroyed using this trick.



Using two 12mm wrenches, hold the inner adjuster nut steady while loosening the lock nut securing the adjustment nut on each side of the swing arm. Just loosen the outer lock nut but try not to move the inner adjuster nut if you can avoid it.



If your chain is too loose then you want to turn the adjuster nuts on both sides of the swing arm clockwise to tighten the chain. Turn both nuts counter clockwise to loosen the chain. Use caution to turn each nut on each side the same amount to maintain alignment of the rear wheel. Note, even 1/2 of a turn on these nuts will make a big difference in chain slack. Speaking of which, now is the time to check the chain slack using Step 2. Check the chain slack again after each adjustment. Tip: make the chain slack a little looser than you want as I find the chain tightens a bit when you tighten the axel nut. I set my chain slack a 1/16" past 2" so that I get 2" when everything is tightened up.

[Fastprof]

Part 3

Step 4, rear wheel alignment. Rear wheel alignment is important to get the most life out of your rear tire, your chain and sprockets. At the worst, poor alignment will cause your bike to steer to one side causing you to constantly correct for this drift at the handle bars. At the best, you will have to replace your tires more often than you should have to.

If you choose to trust the accuracy of the adjustment marks on either side of the swing arm, then simply turn the adjuster nut on the right side of the bike so that the notch on the top of the plate under the axel nut/bolt are lined up with the same adjustment marks stamped on each side of the swing arm. The axel notch and the adjustment lines on the right side are adjusted to match the position of the axel notch and adjustment lines on the left side. First make sure your rear axel is pushed all the way forward in the adjustment saddles by placing a rag or drift punch between the upper chain run and the rear sprocket. Rotate the wheel backwards to jam the rag or punch thus causing the rear wheel to be forced forward in to the correct position.



Remember, do not adjust the left side nut as it is maintaining your desired chain slack. Adjust only the right side to align the rear wheel. Using these marks is how the vast majority of shops set your alignment and is an acceptable method of achieving reasonable alignment. If you are satisfied with the results of this method, then move on to Step 5.

If you believe that these swing arm adjustment marks are notoriously inaccurate I will suggest two alternative methods to setting your alignment. The simplest method is to measure the distance from the center of the swing arm pivot (central pivot where the swing arm meets the frame) to the center of the rear axel.



Measure the distance on the left side, and then use the adjuster on the right side to make the right side measurement equal the left side measurement. Don't be afraid to double check your measurements to ensure the best alignment possible with this method. Note how far off the swing arm marks on my FZ6R are off in the photos below when I use this method of alignment. If you are satisfied your rear wheel is aligned, then move on to Step 5.



If you believe that even pivot point to axel measurements can vary due to mass production tolerances, then using the string method of alignment may be your most accurate method of achieving the best alignment. I will not go into the fussy details of using the string method but give a brief explanation and direct you to a link that does a very good job of explaining this procedure. In this method, you are basically using a string as a straight line on both sides of the rear tire, and then adjusting the alignment of the rear wheel so the strings on either side of the rear tire passes the front and rear of the front tire at equal distances.



This drawing is not very good or accurate, but illustrates the basic concept.
***Note to correct the out of alignment rear wheel below, you should tighten the right side adjuster not loosen it as stated below***



IMHO this method is the best way for a home mechanic to ensure the rear wheel aligns perfectly to the front wheel. Here is a link to a detailed web page on this topic:

SportRyder's Wheel Alignment Method

By the way, performing a string alignment confirmed that my alignment using the pivot point to axel method was dead on for my FZ6R. Caution, your mileage may vary.

Step 5, tighten everything back up. Keeping the rag or drift punch wedged between the sprocket and chain to hold the wheel in its forward position, tighten the axel nut with the 22mm socket. You may have to hold the other side of the axel with a wrench to keep it from turning as you tighten. Tip: I like to always apply a bit of pressure forward on the rear wheel with my knee to ensure it is all the way forward (do not do this if your bike is on its side stand). If you have a torque wrench, you want to torque this nut to 90 Nm or 65 foot pounds. If you do not have a torque wrench, then you want to tighten this nut pretty tight with a power bar. Using a 3/8 drive ratchet with a pipe for leverage is your next best choice (if you did not destroy your ratchet using this method to remove this nut). Failure to secure this nut properly could result in the nut falling off as well as the whole rear wheel as you are riding at highway speeds. I've never seen it happen, nor do I want to. Borrow or buy the proper tools is my best advice.



Once the axel nut is secured, then remove the rag or drift punch from the sprocket. Using your two 12mm wrenches, hold the adjuster nut still while tightening the lock nut on each side of the swing arm. Torque the lock nuts to 16 Nm or 11 foot pounds. If you don't have a torque wrench, just snug it down with a ratchet.



You are done unless you would like to use this opportunity to put a bit of chain lube on your chain.



Hope this post has been helpful. Keep the shiny side up all.

[MNDZA]

Awesome write-up thanks!
Now being dumb, I was lubing my chain today and realized at the end that I was spraying lube on my rear tire the whole time. It has some of that sticky lube all around the left side of it. I tried washing it off, but it doesn't wanna come off to easily. It's not a HUGE amount, but if you touch the left part of the tire, you can feel that it's kinda sticky. Is this a big deal or will it come off after a few miles of slight left curves?

[99vengeur]

Originally Posted by MNDZA

Awesome write-up thanks!
Now being dumb, I was lubing my chain today and realized at the end that I was spraying lube on my rear tire the whole time. It has some of that sticky lube all around the left side of it. I tried washing it off, but it doesn't wanna come off to easily. It's not a HUGE amount, but if you touch the left part of the tire, you can feel that it's kinda sticky. Is this a big deal or will it come off after a few miles of slight left curves?

BE EXTREMELY CAREFUL!!!

Man, you need to wash the tire with some mild detergent, like Palmolive dish soap or something. I would not ride until I knew that tire was clean, but that is just me. Hot soapy water should do the trick, but if you don't wash it, don't ride very hard on the left side. If any of that chain lube is on the treads, it will be VERY slippery for left-hand turns.

Get it off or be real careful.

[Fastprof]

You need to get that chain lube off of the tire. Try a stronger detergent like VIM, but don't get it on your rims as it might scratch them. Scrub the tire with a wash brush and rinse well with water.

[cbzdel]

Lube on the tires is BAD, same reason they tell you not to tire shine MC tires..

[Superfly]

Just found this after searching...great write up!!!

After cleaning and lubing my chain with Motul chain lube I went ahead with the tightening (before I read this write-up)

I was on the kickstand and as soon as I loosened the rear axle nuts the wheel started to pivot out of alignment. I spent the next half hour trying to get it to look right and keep the chain tight. What a pain in the arse. The adjustment marks are kind of hard to line up as the pointers will move quite a bit as you tighten or loosen the nuts. I got it pretty close...marks on the swingarm line up but then I measured from the swingarm pivot and it might be a 1/16" off or so. I think that measuring has got to be the way to go...and doing the job on a stand...not the kickstand...

BTW Motul chain lube is awesome...sprays on like WD40 and dries so nice. Best I've used so far.

[DragonBlu]

It always pays to use a piece of cardboard to keep lube off the tire and rim just as Fastprof shows. Well done sir!

[MikeN02]

Great write up! Can't believe I missed this a few weeks back.