Countershaft nut was not tight!

Just another instance of the CS nut being not torqued at the factory. After 6200 miles I replaced chain and spockets tonight. After unfolding the fold down safety washer I got my buddy (wife) to step on the brake and when I put the socket on the nut it was completely free! I'm convinced it did not loosen up along the way but was assembled that way. The fold down washer was properly secure.

BTW, I did not Locktite the nut during reassembling. My reason is that I plan to change my sprocket fairly often between 14T and 15T. So I'll see first hand if there's any loosening going on.

BTW, I did not Locktite the nut during reassembling. My reason is that I plan to change my sprocket fairly often between 14T and 15T. So I'll see first hand if there's any loosening going on.

The problem with your plan is...... finding it loose,, means it too late..Some to more damage is already done.. Clean all the parts,, put some locktite on the splines and threads,, and tighten that nut. Removing it is a 30 second deal with an $6 puller. Spend another 2 minutes cleaning the hardened thread locker from the splines, install new sprocket.. Repeat procedure.

you need to locktite to prevent rocking on the splines that causes the bushings to go bad and result in a leak and possible tranny problems. They will come loose even with the washer properly installed.

Damn Bronco your fast! :naughty:

I'm quite certain Suzuki tightened the nut at the factory. 6200 miles of use has caused loss of clamping force without any change in position of the nut. The purpose of the Loctite on the splines is more to bond the sprocket in place than to bond the nut in place. The thing to do right now is to torque the nut up to spec (50 to 80 ft lb) and check for free rotation of the countershaft (in neutral) to assure no binding in the transmission.

BTW, I did not Locktite the nut during reassembling. My reason is that I plan to change my sprocket fairly often between 14T and 15T. So I'll see first hand if there's any loosening going on.

Mojave...I switch between a 14T and 15T as well...I've found that using

the BLUE locktite does not present a problem taking it on and off and the

blue locktite adds just enough resistance to the nut coming loose (with the addition of the locking washer of course) to prevent the nut coming loose...

So...

I'm guessing the CS nut should be checked and have Locktite applied on a new bike like mine, just to be on the safe side?

Wow! You guys have read my mind!!! I just checked my cs nut this weekend to change out the primary. After a season and 2500 miles of riding, my nuts was loose also, free play in the shaft (in neutral) no residual factory loctite present, not even a hint of it! Glad to hear of others' observations and Bronco's guidance :naughty: . For safe emasure, should I remove the retainer behind the sprocket to inspect the shaft seal? I feel like I just barely dodged a bullet of mechanical failure. Keeping the sprocket cover off from now on so I can keep a closer eye on what's going on down there... :naughty:

I checked my S yesterday and it was loose. DOH! :D

probably around 500 miles since I checked it..(everything seems fine..)

Now I will check daily.... even if I dont ride it!!!!!

the masters have not failed me yet READ and learn. :naughty::naughty::D

THANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOU

Any theories about what causes the "loss of clamping pressure"? I inspected the mating surfaces of the shaft spines and shoulder, the sprocket spines and shoulder, and the nut. There's nothing wrong. All of these machined features look pretty good.

Before loosening anything I inspected the countershaft rotation - the "feel". It seemed perfectly solid. I could not detect any looseness or binding, nor did the sprocket seem to rock at all. Granted, I couldn't apply much force.

The new sprocket (Sun-star) went on pretty tight. It slipped on and felt just about the way it should.

So, what loosened up? Since the nut can not rotate, either the sprocket shrank or the shaft in between the nut and the sprocket shoulder stretched. I still find it hard to accept either reason given what I see.

With the nut torqued up the rotation is (again) perfect, no binding and no hint of looseness. Since everyone has dogpiled me on this I'll redo the assembling tonight with Locktite. Certainly, everyone should conduct this procedure on their bike.

In answer to the last 4 posts above..

Yes you all should follow the CS sprocket install several members of thios board have come up with,, and hundreds of users here have found to work perfectly.....

One theory is.. that the Nut is not loosening.. but that the sprocket rocks on the splines.. wearing the clamp surface of the nut/sprocket and both sides of the bushings.....At this point the "nut comes loose".. Not really what is happening,, but that is the symptom found.

What we the collective have found to work to prevent this is........to use a thread locking compound,, red, high strength Locktite in my case....to keep the sprocket from moving while in use.

Clean the splines and threads of the countershaft, place about 4 drops of red locktite on the splines where the sprocket will sit. Put 1 drop on the threads. Install, torque the nut, fold the washer.. Let the locktite cure,, (over night is best) Go ride. It will not come loose now. To remove,,, you will need a small 2 jaw puller,, available from most any auto supply store or Sears,, under $8.00. Use that to remove the sprocket after the nut has been removed.

Bronco has explained the theory well. Several years ago, this was researched throughly. There are still some questions on why this happens bit it does and we do have the proven fix. I have always thought there are other approaches to circumventing the problem but where I used to work we had a saying "sometimes you have to shoot the engineers and go into production". The Loctite works, is cheap, and available to everyone, so why look for a better (or different) answer. Never the less, being an engineer, I continue to think about it.

Is this a worldwide problem or just common to US spec machines?I ask because when i have put a question on our UK board about this nobody seems to have heard of it.If they have they are keeping quite about it then!When this subject came up some time ago i went and checked my bike.The nut was still tight and when i removed it the seal and spacer were ok.I put this info in a thread at that time.I`ve put the blue locktite on the splines as recommended but in 4500miles the nut has`nt came `loose`Thanks for making people aware of the problem though.

Andy UK

There is nothing different in the countershaft assy world wide, so I suppose the problem exists every where. It does depend on how often the nut is re-tightened and how much the bike is used. The part that "wears" the most is a spacer inside the transmission. There is a total of 16 surfaces in the assy that can wear to reduce the clamping force. Second gear bushing wears the most. There have been a few reports of transmission failures due to this but really it is not very common

You would think Suzuki could save some big bucks in warranty claims, by simply adding the thread-locking compound at the assembly point. Why on Earth haven't they started to do this?

Or have they? Is this problem ongoing with the 04 and 05 models, or not?

I just bought a 30 mm socket and some red Locktite on my lunch hour, with the intent of doing the fix. But what really bugs me is that I even have to, since it's been an ongoing problem with a model which has been around for awhile. My bike has 400 miles on it, and is only a month old. Seems insane that I'm having to pop the CS nut and Locktite the thing, when the paint is barely dry on the bike.

Are you listening Suzuki?!

Whoa, wait a minute. Doesn't the sprocket shoulder just push up on the shaft shoulder? I'm sure that's it. The nut pushes the sprocket against the shaft shoulder. It's clamped there, it's isolated from anything past the shoulder. This is a critical mechanical issue. Why on earth would you involve bearings and seals further in with something as gross as just retaining the drive sprocket? I've never seen anything like that. I don't have any idea what the innerds look like but I bet the shaft bearings are preloaded internally.

BTW, the as machined surfaces are present on my old sprocket, nut, and shaft shoulder. The washer doesn't look worn. There is no wear from free motion. If the nut started off tight then I think something either compressed or stretched.

Bronco has explained the theory well. Several years ago, this was researched throughly. There are still some questions on why this happens bit it does and we do have the proven fix. I have always thought there are other approaches to circumventing the problem but where I used to work we had a saying "sometimes you have to shoot the engineers and go into production". The Loctite works, is cheap, and available to everyone, so why look for a better (or different) answer. Never the less, being an engineer, I continue to think about it.

Well said. My wife is ALWAYS asking me why I cannot be satisfied with something. I tell her that I am satisfied with her and my son. But with anything that is machanical, I will roll it around in my noodle until I have come up with some way to make it better (at least for me). It is a bad habbit. But it has helped in the past with projects. It doesn't cost anything to think about it.

As for this problem, I have never laid eyes on it myself, but I envision a stiff polymer washer that will keep tension on the two parts that need to be held (which sounds like the job of the washer) but make sure it has a user life that won't run out. Perhaps use a "potatoe chip" washer made of spring steel to fill the space, but flattens out under the specified torque pressure. Just thinking outloud.

A polymer washer isn't what you'd use. Plastic is, well, plastic. It will deform over time and release the compression. A properly torqued steel fastener has been stretched a pre-define percentage of it's elastic limit by the torque. 79 ft-pounds is getting in that region for a shaft of that diameter. Presumably the steel doesn't "relax" over time. It's a mystery.

It is not a mystery. PM me and I will send a full report if I still have it.

Suzuki does not read TT. Suzuki Corp has no problems. C/S nuts don't come loose. Water pumps do not leak. The auto cam chain tensioner was never a problem (although they changed it 3 times), the C/S seal does not leak.......... etc, according to Suzuki!!!!

I have no doubts about the fix. I also know manufacturers don't always make good design decisions. And, I don't doubt there's a reason. But what is it?

If the CS nut really does clamp through the shoulder on further into the assembly then that has to be the biggest engineering blunder I've ever seen.

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