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Is my chain adjusted properly?

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It seems like with every thread concerning chain tension comes around, you see the same old answers. The majority of suggestions are given because a rider finds that their method seems to work for them.

Actually, giving a person the recommendation to use the 3 finger method is quite silly. I mean, we all have different sized appendages, and 3 fingers for one may be 4 fingers for another.

Also, when we have a chain tensioned correctly, there is a very fine line..and only about a 1/4 turn of the tension adjuster, to take the chain into way too tight.

Providing pictures of your bike and claiming a person should tension it the same is crazy. The tensioning procedure is far to easily hosed up to simply look at someones picture and be able to make anything at all from it.

I have studied the proper adjustment of chains and sprockets for years.

I find that one of the biggest problems folks have is misinterpreting the manuals suggestions.

For an example, the latest Yamaha 450 manual gives a check range of 1.9-2.6 inches from the back of the top chain slider to the bottom of the chain.

After doing a check, I find that this measurement range is about right on. But, do you check this while the bike is on the ground, or while the bike is on the stand? And there lies one of the discrepancies I mentioned....

But where do these moto engineers get the proper recommendation for chain tension in the first place?

They use standard engineering practice for chain tensioning...and they pass that textbook information along to the owner, taking into account the length of chain on that particular model bike.

The engineering practice they use is the very same for each and every bike, but what changes is the numbers due to how long the chain is...or closer yet, to how long the distance between shafts is...which is what actually determines how taught a chain should be.

If you were to use the engineering standard to tension your chain properly, you could then go back and check the measurements that the manual gave you. And you would find that they are indeed very close to what you found.

But only if you interpreted what the manual was trying to convey to you properly.

I see so many folks who will swear that stock OEM chains are nothing but cheap junk and should be shucked immediately. But that is not really fact.

Yes, the OEM chain may not be the top shelf quality chain that your moto supply may want to sell you, but it is almost assuredly of a good quality that will last a rider for many rides before it is trash...IF the rider has it adjusted and maintained it properly.

An improperly adjusted chain can only live so long..and even the high-dollar choices will be trash fast if they aren't properly mounted.

I'd have to say that the biggest mistake I have seen over the years is folks having their chains too tight. When a chain that is too tight lands a jump and compresses the shock, the overly taught chain eats away at the sprocket teeth, the chain itself, wheel bearings, CS seals, and on and on....

SO many times a rider will then swear his stuff is crap, and start looking for harder and more robust equipment that can handle their improper adjustments better.

I contend that if you properly adjust your equipment from the get-go, you will find that even the OEM equipment will provide many hours of riding. Your high dollar replacement equipment will also last longer.

The Procedure:

You first need to put the bike on the stand and remove your shock.

Before you do anything, simply take the swing arm through it's motion of travel from top to bottom. This is the point where many are convinced something is amiss right away, as they often find that there is a point in that travel that the chain gets completely tight. Bowstring tight in many instances.

This often will open a persons eyes who has thought they were tensioning their chain properly, but were in reality over tightening it.

The tight spot will be when the CS, swing arm, and rear shaft are all in perfect alignment. When you have the bike in that position, you want to use a cargo strap around the seat and the rear wheel to hold the swing arm in that tightest position.

chnsag3.jpg

Once you have the swing arm in the tightest position, you can then adjust the chain tension. The engineering standard for chain tension is to have between 1%-3% of the distance between the front and rear shafts in total up-and-down chain movement when the chain is at it's tightest point.

For instance, if we have a bike that is 24" between the CS and rear shaft, the correct tension for the chain will be between .24" and .72" of total up-and-down free play of the chain when at it's tightest position.

Knowing this measurement, you can initially adjust the chain to the .24" mark, and retention once you get to the .72" mark. If this is done, the chain will always be within the recommended tension rage, according to engineering standards. Some may find they feel more comfortable staying within the 2%-3% range.

Let's assume you want to start out with the 2% mark and retention when you reach 3%.

At 2% of total up-and-down free play would be .48"

chnsag2.jpg

Note that the tension on the illustration shows the chain having .24" of free play when it is pushed down. And as such, it will also be able to move when pulled up by the same .24"

This means that you have a total of .48" in total up-and-down free play in the chain. You are tensioned at the 2% mark.

chnsag1.jpg

Once you have the tension proper, you want to make certain you still have proper alignment if the sprockets.

When everything is nice and aligned, and you are satisfied that you have the proper tension on the chain, you want to make certain everything is buttoned up tight, and you can replace the shock. It is best to recheck everyting before you replace the shock, as things can change a bit on you once you have the adjusters and axle bolt tightened. Take the time to check and recheck until you have it spot on when tight.

Once the bike is adjusted properly, and back in running condition...THEN you can check to see what that properly tensioned adjustment gives you when the bike is on the ground...or on the stand for that matter. What you want to do at this point is have some sort of reference so you can check the tension without going back through the shock removal procedure again.

If you find that the properly tensioned adjustment gives you three fingers under the chain, behind the slider, when the bike is on the ground...then fine. Use that to determine if you are properly tensioned. But don't tell anyone else that is where they should have their adjustment, it simply may not be correct.

To take this further, which is what I do whenever I get a new bike, is to first tension the chain at the upper limit of tension or the 3% mark.

I then button everything up and check to see what measurement that gives me when the bike is on the stand.

I can from then on see with an easy check when my chain reaches a point that it needs to be re-tensioned.

I then go through the whole thing again adjusting the tension to the 1-2% mark, and recheck to see what measurement that gives me when the bike is on the stand.

I now KNOW what measurement I should have for properly tensioned chain and chain that needs to be re-tensioned, when the bike is on the stand. I never have to go through the painstaking procedure of removing the shock to properly adjust for tension again.

Some will actually cut a GO/NO GO block of wood or plastic to use as a gage.

And a proper gage block will have the distance of a properly adjusted chain on one side, and a larger measurement on the other side that will tell when the chain has gone further than the 3%.

Many folks have gone for years improperly adjusting the tension on their chains. Many simply accept that their equipment wears out fast...and some find excuses for it like, the chain is junk, or their beastly bike simply is too much for the chain and sprockets to handle...but neither is the usually the case. The truth is that their tensioning procedure is placing undue stress on their equipment, and if they would take the time to do things a bit differently, they may well find that stuff starts lasting a lot longer.

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...The tight spot will be when the CS, swingarm pivot, and rear axle are all in perfect alignment...
:applause:

DigilubeJay's post deserves a sticky. :ride::thumbsup:

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I am way to lazy to remove the shock to tighen my chain...

So don't then ... just use a ratchet strap to compress the rear suspension then.

:thumbsup:

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Great post!

Thanks, I'm going to make a reference block the next time I service the swingarm & shock.

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See great posts like these should be stickied. Other wise people will never see them. There probably ahave been 1000's of great posts like these but people never see them since they aren't stickied or put in the technical forum.

So I think we should have a mod that goes over all the technical posts or posts that are tips that people found and put them in one forum.

OK, enough complaining for this month from me.

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Oh, dude...or you could just use 2 or 3 fingers under the rear chain slider bolt. :thumbsup:

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Yes, you usually can, but he covered why that sometimes doesn't work. Besides, DLJ hits an important point or two here that would be wise to bear in mind, and are instructive at the least.

> The point in the suspension travel where the maximum chain tension occurs is the point at which the centers of both sprockets and that of the swing arm pivot are aligned. You NEVER check the chain tension with the suspension in this position under normal circumstances because it generally isn't the least bit practical to do it that way. But as he said, it is from the tension at that point that the figures quoted in the service manual are derived. Tension is set in the aligned position to a high and low limit, the bike is returned to the stand, and the tension found is written up as the correct slack to run with. It's good to understand where those numbers come from, and why.

> Understand what the manual says. The '03 YZ450 service manual quotes a figure of 1.6-2.0" from the rear chain slider bolt to the chain, with the chain pulled up. But that's a vertical measurement from a certain fixed point. That is NOT 2.0" of slack in the chain. There's a difference, and it's important to get it right.

> You can't check the tension with the bike on the ground. Why? It isn't consistently repeatable. The sag will vary, and thus the readings will vary with it. With the bike on the stand, the suspension position is the same every time, so the measurements you get are valid. If you've measured the chain tension as he suggests, or established that the numbers in the manual are trustworthy, the go/no-go block is a good idea. A socket of a known height, etc., can be substituted, as can your fingers....IF you've measured them, and they're the right size.

It's a good writeup, and it belongs in the tech section.

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Many times folks will use the manual more like a bible than a point of reference. The thing is, manuals often times are misleading, suggest a very clumsy approach, or are just flat out incorrect. The latter is a very rare occasion, but due to the details becoming hosed up during language translation, or perhaps the proofreader didn't have the mechanical prowess they should have, things sometimes get fouled up by the time it gets conveyed to the bike owner.

That is one of the reasons I like to validate the measurements given to me by the manual. Once I have done the shock removal procedure twice, I can check both the lower and the higher end of the given measurements to insure that they are indeed correct.

Yamaha seems to be real good at providing the proper numbers for most of the bikes I've checked. However, KTM manuals are in dire need of some help.

The recommendations they give are very misleading. They even show the bike on the ground resting on a stand when they provide the check numbers.

Like grayracer stated, checking a bike...or wrenching for that matter, while the bike is resting on the rear wheel is not practical. Nor is it going to provide you with the proper adjustment. I am fairly convinced that KTM means you to check the chain tension while the bike is on a stand, but they do not convey as such in the manual.

They have even had to provide little stickers on the swing arms of newer bikes in an attempt to fix up their mess...which complicated and threw more smoke at the already screwed up situation. They still don't have it right.

Many times you will hear riders saying things like; "KTM needs a looser chain than other bikes". But that is not really the case. All bikes need the same amount of tension placed on the chain, which is 1%-3% of the total shaft to shaft distance.

The real problem with the KTM bikes is that the manual has folks placing bad adjustments on their chains, and as a result the KTM's are notorious for trashing chain, sprockets, wheel bearings, CS seals, and on and on....

You KTM riders try the shock removal method one time...then check the measurement you got to that of the manual. But, forget about the bike being on the ground, check things from the stand.

Two more things I want to touch on with chain tension adjustments;

If you ride in the mud. I'm talking mud. Then you may often find that your chain gets completely covered in mud and grime. Having a chain full of mud can cause the tension to be tight.

Normally this can be overcome by using a sprocket that has mud reliefs cut into it. They will allow excess mud to be pushed out around the side of the chain. Another helper is to use a chain lube that does not create a cruddy mess and collect dirt.

If you find that you are going to be riding on a very muddy day, it may be a good idea to not have your tension set at the tightest end of the tension range. You may be better off tensioning to the middle or upper end of the range for that days ride.

Many folks will proclaim that they are mud riders and they feel that the mud is what is eating their sprocket teeth away, but it is more likely that the mud is causing a tight tension situation, which is what is really eating their chain and sprockets up (among other components).

Most everything I have touched on so far is based on the equipment being in good condition.

Many times our equipment is not in the good condition we may think it is. Take O-ring chains for a prime example.

Riders will often neglect their ring chains, as folks tend to feel like they are maintenance free items. But they are not maintenance free. They need to be cleaned and lubricated on a regular basis. And they should also be inspected often. It only takes one or two rings to be torn or worn to allow water and contamination into the protected area. When this happens, it is very likely that that one or two reels will experience wear far faster than the other still protected reels. Also, these violated links that have water and dirt in them now, can cause the chain to "kink" up. If you don't know what I mean by this, simply take your ring chain off and see if it rolls smoothly in your hand in a concentric manner. That kinked up feeling that 99% of you felt when you did take your ring chain off, is what I'm referring to. If you didn't find a kinked up chain, you probably didn't remove it and check....

I won't waste time arguing with those who think ring chains are God's gift to the moto world, but I will say that if you use a ring chain, you need to be very careful when tensioning your chain. If the ring chain has some fouled up links, it can cause the chain to have a tight spot(s) when rolling it around the sprockets. If you find that your chain does indeed have a spot that the chain tightens up each time it goes around, first make certain that you only tension the chain when it is at it's tightest position.

So basically what I'm saying is; once you have your swing arm in the tightest position, roll the chain around a few times and check for a tight spot. If there is one, adjust tension from there.

Even if you don't run a ring chain, it's a good idea to check for tight spots, as some sprockets can be out of round just slightly. If it is slightly non-concentric for whatever reason, it will normally only show when you roll the chain around the sprockets.

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Great post! Well done.

I'm waiting for BMW, or someone else who knows how, to create a swingarm system for dirt bikes. Have the swingarm pivot on one side and perfectly lined up with the countershaft sprocket so you will eliminate chain stretch caused by the misalignment. Now you only have to adjust your chain for wear and stretch caused by massive amounts of horsepower and terrain boo boo's.

That would be sweet! Hmmmmmm, what's this stuff in my corn-cob pipe?

Dave

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My neighbor needs to read this, He has his chain so tight there is no slack. He isnt the brightest when it comes to bikes.

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Great post, very detailed, but that is way over complicated for a 5 minute job.

1. Put bike on stand

2. Adjust chain so that 3 finger fit between slider and chain

3. Put bike back on ground, sit on it, if the chain seems really tight when you sit and make the swing arm parallel to the ground, then put some more slack in it. If it seems loose, take out some slack. Of course you would do the adjustments with the bike back on the stand.

Then your done, finished, and can go riding. I dunno about other bikes, but unbolting the rear shock and stuff is not fun, nor fast. And unless you have a quality chain, you have to adjust it often, and un bolting the shock every time would get old and stuff.

Not to knock on your tutorial, cause it is very well written, but its not like we are replacing a transmission here or something, just thought I would offer an alternative.

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Good, but a loose chain will wear your sprockets far faster than a too tight chain with the latter 'supposedly' wearing more on countershaft bearings though I've not seen any posts on the latter ever happening, either.

Too tight would also stretch your chain out very fast and THAT would ruin your sprockets long before anything would happen to the countershaft.

Two to three fingers play at the middle of the chain while the bike is on the ground is fine without being too technical.

Additionally, people try to make it even more complicated by 'put it on the stand, take it off, check it.........blah, blah, blah'.

Why would you EVER put the bike on the stand to adjust the chain except for maybe putting on a new chain? Do you ride the bike on the stand? How much is your bike ever in that position? And if it is maybe 1% of the time when jumping, the position is MEANINGLESS overall because it is a GENERAL STARTING POINT which you can get when the bike is ON THE GROUND. You adjust it on the ground for the first GENERAL STARTING POINT and then you check it with your weight on it which is the position it is in most of the time. Don't put it on a stand and take it off and put it on. That's just a waste of time and effort.

If the wizards of the world were really smart AND really worried about this problem they'd make a chain tension indicator which need be nothing more than a fish weighing scale. Then each manufacturer would tell each person what weight is perfect for their bike and their chain...........but you know why they don't? Because it IS NOT THAT IMPORTANT and it doesn't matter as the chain will last a long time within a general range of tension as long as it's not extraordinarily tight or loose. All the technical mumbo jumbo is meaningless and nothing more than a waste of time.

Don't worry about the technical ramblings which are actually meaningless because you can get a starting point tension with the bike in ANY static position. Don't waste time putting the bike on a stand. Somebody already gave you the answer of '3 fingers' and then check it with your weight on it. That's it.

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...I'm waiting for someone to create a swingarm system for dirt bikes. Have the swingarm pivot lined up with the countershaft sprocket so you will eliminate chain stretch caused by the misalignment.
Great idea! I'm not sure if anyone has tried that yet (I think there is a mountain bike with that design), but one of the actions caused by the current design is rear suspension "squat" under acceleration. It was much more pronounced on earlier bikes where the swingarm pivot and countershaft sprocket were much further apart (2-4 inches), but it also caused lots of chain derailment issues when bike's suspension travel grew. Many riders like the bike hunkering down when they pin it, plus it rakes-out the front end, helping stabilize the bike. A swingarm designed with its pivot concentric to the c/s would nullify that effect.

Kawasaki had a 4-link rear suspension ("Fubar", I think it was called) that did much the same thing, back when Jimmy Wienert rode for them. :thumbsup:

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...He has his chain so tight there is no slack. He isnt the brightest when it comes to bikes.
Recently, we were at an indoor track with a guy who's chain appeared too tight. He was a good rider, and never had any problem as long as he "greased" the landing on the big double. But about once or twice a session (maybe 3 to 5 times that day) he would come up a little short with the back tire, and when he did, the rear suspension would recoil, (restricted by the too-tight chain) and launch him over the bars. :thumbsup:

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