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Counter Shaft Sprocket "Loctite Fix"

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This preventative Maintenance "fix" is applicable and recommended for ALL YEAR and model year DRZ 2000 -2013

Why does my counter shaft (C/S) sprocket get loose? Is it the nut? Or something else? The “Loose” sprocket” situation in most cases really is not what it seems; the C/S nut is not coming loose. Though that can be a contributing factor. http://www.thumperta...=1&d=1277642132

24 CIRCLIP
18 WASHER
15 GEAR, 3RD DRIVEN (NT:22)
16 GEAR, 4TH DRIVEN (NT:24)
21 WASHER, 1ST DRIVEN LH
13 GEAR, 2ND DRIVEN (NT:26)
14 BUSH, 2ND DRIVEN
22 BEARING, DRIVE SHAFT, LH
34 SPACER, ENGINE SPROCKET
33 SPROCKET, ENGINE (NT:15)
38 WASHER
37 NUT, ENGINE SPROCKET

These are the parts that are located or clamped togeather between Circlip #24 and the Countershaft sprocket nut #37 The theory, which in follow on years has been substantially proven though wide spread use of the “Loctite Fix” and follow on inspections. Is that wear of the C/S second gear bushing is what causes the “loose” C/S sprocket nut. Users find the C/S nut loose and then tighten the nut, against what is now a worn, mushroomed bushing, this causes bind in the counter shaft. A little may go unnoticed for many miles, a little more bind, and the bushing will seize to the gear, counter shaft or both. Causing hundreds of dollars in repair and possible a crash when the transmission sizes. It's believed the primary cause of second gear bushing wear, is the slight rotation of the sprocket on the counter shaft. There is not an interference fit between the sprocket splines and the counter shaft splines, which is what allows this movement.

TT User Noble and Sargentrab, the original investigators of this issue initially thought the second gear bushing wear /deformation was caused by over tightening the nut...

Quote
“being crushed from torque on the nut. In other words, the nut did not back off, the parts being clamped together got shorter so the clamp load decreased until the nut was loose. So my remedy was to use 50 ft lb rather than 80 specified by Suzuki to decrease the compressive load on the frail looking bushing. After testing, using parts from Sargentrab's transmission, I now know the 2nd gear bushing is not damaged by torque on the nut. Using all actual Suzuki parts, I tightened the nut to various torques up to 120 ft lb. At 120 the threads pulled out of the nut. No damage to the bushing. I then replaced the countershaft with a 7/8 fine thread grade 8 bolt so I could torque to more than 120 ft lb. With this set up I could go 150. At 150 my vise gave up. Still no damage to the bushing. So the bushing is not easily crushed and it is a lot stronger than it looks. As far as other problems, 1 of the 2 test bushings started to bind on 2nd gear ID at 80 ft lb and the other bushing started to bind the gear at 100 ft lb. Both bushings were very tight to 2nd gear (would hardly turn) at 150 ft lb. Both bushings, even after the 150 ft lb test, seemed fine again at 50 ft lb showing no binding on thrust face or ID/OD interface. Both test bushings were used and slightly damaged to start with but came out of otherwise good serviceable transmissions. At this point I am willing to accept that Suzuki did not make a mistake specifying 80 ft lb torque on the nut and 80 ft lb is OK to use with new bushings and with bushings in good condition.-------------------------------------------------------------------------------------Noble 2003

So we have identified the problem as, loose fit between the C/S sprocket splines and those of the countershaft. Again Noble noted

 

Quote
“By measurement and observation, 2nd gear bushing does get shorter and it does get fatter (the OD on the open end gets larger). If not by crush, then how? Answer: wear. How does it wear if it is clamped in place and can't move? This is where the explanation gets tricky. Wear may not be exactly the right description but there is a kind of wiping, wearing, mushrooming action that takes place when a nut is tightened onto a washer. Take a look at the washer under the rear axle nut for example. Both Sargentrab and myself independently came up with the same idea on this. The sprocket is driven by splines. The splines have a small amount of movement (backlash). The torque on the nut makes the sprocket seem locked to the shaft but the reversing drive/driven load actually causes the sprocket to shift back and forth on the splines very slightly. We did not prove this with tests, we are just looking at the results and speculating. With the nut loose we tested various sprocket/shaft combinations for fit: total of 3 shafts and 8 sprockets. 2 sprockets were brand new. The shafts were all used but showed no significant wear. Backlash measured at the tooth of a sprocket was on average .010. We measured from .006 to .015. OEM Suzuki sprockets were about average. Inspection of used seal spacers, thrust washers, and 2nd gear bushings all show rotational wear patterns with some burring. “ ----------------------------------------------------------------------------------Noble 2003

 

This theory was originally derived from inspection of three DRZ transmissions, but has since proven true with many others, to include my own and many I have worked on over the years.

The Fix, or.. How to:

The fix: As the root cause issue is clearance between the C/S splines, and the sprocket the fix is focused on that. Using an Anaerobic threadlocker (AKA Loctite) that cures to thermoset plastic when it comes into contact with metal in the absence of air, used on the splines and C/S threads has been proven on hundreds, if not thousands of DRZ’s to stop the rocking motion of the sprocket and thus the wear of the second gear bushing solving the mystery of the “loosening C/S sprocket nut”

The procedure: What brand or type Anaerobic threadlocker you use is dependent on what is available in your area. The established standard shown to work when done as advised is Loctite brand (Henkel corp) High Strength Thread locker PN 271 263 (NOTE: Henkel corp Updated their product line.. 263 is now the correct product number, replacing 271) .

In the years since this procedure was established we have had two employees from Loctite visit the forums and speak on the use of Anaerobic threadlocker for this application. One company representative stated emphatically the use of a thread locker would not work, he implied we were idiots for trying and wasting our time. When it was pointed out that we had been using Loctite 271 for many months and it in fact did do what we needed. The company rep implied we were idiots and never came back.LOL

The second company representative , had a much better attitude, was very helpful and stated, while he acknowledged our success in using the 271 product, a better option was available. Loctite retaining compound 680 or 638 was recommended.

The problem is, that product was marketed for heavy equipment or  industrial use and not widely available. Some members have not been able to locate these products at any location industrial or not. Others have found 680 or 638 at Farm equipment suppliers (John Deer) or Fastener and bearing suppliers are great places to find Anaerobic threadlocker or retaining products used on heavy equipment or industrial machinery.

Which brings us back to the tried and proven to work commonly available Loctite brand High strength threadlocker 263. This is the product recommended, many other like products will work I’m sure,, If 263 is not available to you,, Choose a like product from another manufacture.

Start with removing the counter shaft nut and sprocket, clean and degrease the threads and splines using brake or contact cleaner. Remove all scale and rust. (Note, on rare occasions the sprocket may be difficult to remove due to rust or corrosion. Or if this is a used bike, a previous owner may have already done the Loctite fix. And the sprocket will likely need a small two jaw puller to remove),

Remove and clean the spacer, and check the O ring behind it and replace. If the spacer is deeply grooved or pitted / rusted. it will need to be replaced, and the seal as well.

Apply 4 drops (More is not better, if you douse the splines and the loctite gets under the spacer and into the seal area, once it sets, the seal can be damaged) of 263 to the splines of the counter shaft, just outboard of where the sprocket will rest once installed. Distribute the drops around the shaft evenly.

The threadlocker tends to wick into the spline gaps, so you really do not need to slather a lot on to get the job done. Install the spacer and o rings onto the C/S, and then the sprocket.

Use a drop of 263 on the counter shaft threads and install the lock washer & C/S nut. Using the chain as a holding tool, tighten the C/S nut to 105 ftlb.

Remove the chain and rotate the countershaft by hand, It should rotate without any binding. Some drag will be present and is expected. If it rotates freely, then you are good to go. Bend the locking washer over, let the thread locker cure for a minimum of 8 hours and go ride. There is a lot more to anaerobic thread sealant and thread lockers, Different types, primers that can be used to prep the surface and or speed cure time. Cure time based on temp, air in contact with the product, type of metal in contact… And that would make a great 20 page thread in the general forum… But the bottom line, no matter what the product data sheet says for Loctite brand High Strength thread locker 263. No matter what a company rep may say. It works in this application.

Removing the sprocket after installing it using Loctite 263: Lastly, we come too, “How do I get this sprocket off, once I have installed it using Loctite 263 to help fix it in place?”

Anaerobic thread sealant does become soft when heated. The problem with heating the counter shaft and sprocket is, there are o ring and a seal that reside right behind that sprocket which might be damaged by the heat. So go easy.

Use heat on the nut to soften the thread lock, then remove the nut.

Then;

The simplest method I and others have found to remove the sprocket is to use a small two or three jaw gear puller. Commonly available from most any automotive tool supply house, or Sears for that matter. . Rent or buy the puller, it’s a good tool investment.

Using the chain and rear brake as a holding tool, flatten the lock washer, and remove the C/S nut. If you use an impact gun to remove the nut, make sure the transmission is not in gear.

Remove the chain, and place the puller jaws over the sprocket. Make sure the puller screw is centered in the counter shaft. Apply some pressure to the puller. If you use an air impact gun, the sprocket will come right off. If your using a ratchet or wrench, tighten the puller, then give the center screw a light rap with a dead blow hammer.. The sprocket will break free and can now be removed.

New or updated information and products would always be welcome. So if you have something new, quote this thread and start a new one. Let’s discuss it and see what comes up. Thanks. Thanks for looking, Fix that loose sprocket and go ride. I’d like to thank Noble and Sargentrab for their original work in discovering what was causing this problem, and devising a solution that has been proven with the test of time.

Parts required for the repair of a leaking counter shaft seal are:

SEAL, DRIVE SHAFT OIL 09283-30053
SPACER, ENGINE SPROCKET 27531-29F00
O RING (D:2.5,ID:21) 09280-21008

Often the screws holding the seal retainer are damaged if you attempt removal without first heating them to 250c to loosen any thread locking compound, and do not use an impact screwdriver. If danged and need be replaced,they are BOLT, RETAINER (6X14) 09126-06007

However they can be replaced with common hardware, countersunk screw, grade 8.8 and above 6mm x 14mm

Replacement nut and washer are:

ENG SPROCKET WASHER 09167-22012

ENGINE SPROCKET NUT 09140-18006

If you just a complete parts kit, here's one from All Balls (also sold under the brands of MSR and Moose):

https://www.thumpertalk.com/shop/All-Balls-Counter-Shaft-Seal-Kit-p4797952.html

Counter shaft assembly.jpg

spacer and o-ring.jpg

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