New Chain and Sprocket Install 950 Adventure


This is a step_ by_step How-to on replacing the chain and sprockets on a 2003 KTM 950 Adventure, but the same principles apply to all chain driven motorcycles.

The new gear this time includes an OEM Super Enduro rear sprocket with 45 teeth (compared to the OEM Adventure rear with 42T) and a DID 525ZVM2 X-ring chain. I'll also install a Zip Ty Racing CAB10 Chain Adjuster Block Kit.

And upgrade to an Evoluzione clutch slave cylinder and a CJ Designs (cjracer) clutch master cylinder reservoir while I'm at it.

The old chain (an OEM type DID 525 HV) has ~20k miles on it and is still in spec. ie: 18 links are <272mm). I replaced it for my upcoming Alaska adventure tour in June. First step is to get most of the old chain lube, mud, and road grime off.

Being from the "old school" I always use diesel fuel for this task. At the cost of this stuff lately, I could use Llanllyr Sparkling water.

After cleaning things up a bit, I started removing the necessary bits to get to the front sprocket.

The OEM slave cylinder was still in good shape, so I'll save it in case someone on the OC needs one in the future. It's not likely I'll ever need one again, as the Evolutionize unit is incredibly well built. Note: DON'T squeeze the clutch lever with the OEM slave detached from the engine. Word is that "You WILL be buying an Evoluzione unit" if you do. 'Nuff said.

This is the plastic inner spacer that folks have had so much problems with in the past with the OEM cylinder. This one is pristine. A result of the fact that my clutch gets very little use (mostly just starting up and stopping). It will be reused with the EVO unit. A note about not using the clutch for shifting a motorcycle transmission. If done "properly" no damage will occur to the transmission. If done improperly, you can trash your transmission. It takes impeccable timing and muscle coordination to pull off successfully. Don't try this at home, kids. And whatever you do, don't try to learn this tricky technique on your beloved Katoom. Nuff said.

Next the sprocket cover and case saver are removed (8mm socket)

Unbend the retainer washer. It can be reused if you bend a different section each time, but it only costs $1 USD, so why not keep a few in your toolbox and put a new one on each time?
Note1: If you're R&R'ing the 17T sprocket, you need to align the space between the teeth with the groove in the swingarm pivot. If you don't the teeth of the sprocket will hit the swingarm an stop removal.
Note2: If the splines weren't coated with anti-seize last time the sprocket was R&R'd, you may need to use a gear or sprocket puller to get it off. If you use heat to help "persuade" the sprocket to come off, be advised that there is a rubber seal directly behind the sprocket that can be easily damaged. Careful about pounding on the end of the shaft. It costs ~$140 USD, but is a PITA to replace.

Find the old masterlink if the chain has one. It'll have pins of different color from the rest. If your chain doesn't have one, pick any link.

Now grind the mushroomed part of the rivets off the link with your favorite die grinder. You can grind off one or both rivets. I grind off both because of the method I use to push the pins out in the next step. It is only a 10 second job either way.

It'll look something like this when you're done. You don't want to try to break a staked rivet chain of this size and quality without doing this step. Modern high quality drive chains are made from some very tough materials. The result of skipping this step will surely be a broken chain breaker tool (no matter how much $$$ you paid for it).

Here's the tool I use for this job.

It contains everything needed to break and rivet most any size chain you'll find on/in a motorcycle. Even camchains. It's around $90 - $95 USD depending on where you get it. You can buy cheaper tools to do this job. I have found that you "usually" get what you paid for when buying tools. Tools are a multi-generational investment in my family, so I usually buy the best I can afford.

With the proper size press pin in the tool, the chain pins of the masterlink are easily pressed free of the outer plate. Refer to the Instruction Sheet for this tool for the proper usage. You can press one pin out and rotate the plate out of the way, or press both pins out and the plate just falls off, your choice. Once the pins are ground off, they push out very easily with the proper tool.

The remainder of the master link can now be removed and the chain slid off the sprockets.

This is the top bolt of two (the other is on the bottom of the swingarm) that hold the chain slider to the swingarm. This has come loose on several late model 990's, probably due to improper installation at the factory, and jammed the front sprocket causing a very unsafe situation (think locked rear wheel at speed). Everyone (no matter what year/model bike) should check these two bolts and reinstall with red Loctite. The consequences of one of these coming loose is just too great to chance.

Check the slider for wear at each chain replacement. This slider is in great condition, so I just cleaned it up and reinstalled it. The arrows point to the mounting points that require Loctite bolts.

While the sprocket cover and slave cylinder are off, it is a good time to check the clutch oil jet. This should be done at each oil change in any case. If the small hole in the jet becomes clogged, the clutch parts can be damaged during hard use and require replacement (6mm allen wrench).

I've found the best tool for R&Ring jets such as these to be a #4 or #5 hollow ground gunsmith screwdriver. If you installed the jet properly last time, it shouldn't be more than just snug in its threads.

The best way to remove the oil jet, after it is unthreaded, is one of these slot screw starters. The spring loaded tip grips the slot in the jet and allows it to be lifted out quickly and easily.

A .010" steel guitar string works good to clean out the rather small hole in the OEM "30" jet. This photo shows the size of the stream of oil that is required to keep your clutch alive. Be judicious in the task of cleaning it.

This tip and photo by ADVMax:
"I will add this suggestion, however, after hearing several people mention that the front sprocket was a bitch to get off - Never Seize is your friend."

This is the OEM 17T front sprocket. I installed it temporarily to check the chain length. Note the rubber coating on this sprocket. It is applied to the surface only and is there to help quiet chain noise for strict European noise regulations. Originally the 950 was designed to use a 16T front sprocket. The 17T was added later as part of an effort to quiet the big twin enough to pass these noise regs.
Handy tip: to R&R the front sprocket on the trail, use the axle box wrench from your tool kit and let it jamb against the swingarm pivot. Then use the rear wheel to turn the sprocket and loosen the nut. You can do the same thing in reverse to install the nut.
You can see here that the teeth of the 17T run through the slot in the swingarm pivot and how the space between the teeth needs to be aligned with the slot for the gear to be removed.

While I had the rear wheel off, I installed the new ZipTy Racing quick change chain adjuster blocks and axle. The adjuster block on the other side is pinned to the brake caliper mount, so everything stays aligned when the axle is removed to change tires. Makes for a very quick and smooth operation. The folks at ZipTy are good people and always answer my e-mails promptly.

The new DID 525 ZVM2 X-ring chain is the strongest in its class.
Update: After 15k miles, the ZVM2 chain hasn't needed any adjustment whatsoever
The standard 120 links of the new chain (OEM length is 118 links) were perfect for both the 17T front with the 45T rear and the 16T front with the 45T rear. Only requiring 3 full turns of the adjusters to go from one to the other, and plenty of room to the rear for adjustment over the chain's lifetime. I couldn't get the 118 links to fit with the 17/45 combo. The 16/45 will work if the OEM adjuster blocks are flipped. No problem adjusting with the ZipTy adjusters as they will adjust through the full length of the axle slot in the swingarm (no need to flip).

Lube up all four X-rings and both plates and pins of the master link with the included pack of lubricant.

Now carefully press the outer plate over the pins on the master link with the proper chain press attachments.

Don't go overboard when pressing. The plate should be pressed on to the same position of the adjacent links. You can check this with a caliper or mic.

The proper anvil and rivet head is then inserted in the tool and each pin head is mushroomed to a thickness of .40mm (.016") greater than the pin diameter.

Pin diameter on this chain is 5mm, so I mushroomed the pin heads to 5.40mm. This step is critical, as unless done properly, the chain may come apart and damage you and/or your beloved Katoom. Too tight isn't good either. Here's a place where "just right" is the word.

I then installed the 16T front sprocket for use on my local trails, blue Loctite, and torqued the countershaft nut (32mm) to 100nm. You can put the bike in 1st gear and/or hold the rear brake to keep the sprocket from turning.

And bent the new lock washer over one flat of the nut.

Then its just a matter of reinstalling the parts in the order they were removed. Be sure that the retainer pin is in the hole in the clutch pushrod before installing the hydraulic clutch adapter.

Then the chain fail protector.

And the slave cylinder spacer.

Now bolt up the slave cylinder. In this case a new Evoluzione unit. A handy tip: if, before you mount up the slave, you remove the master cylinder cover, and hold the slave cylinder horizontal with the logo up, then slowly push the piston in, you will get a much quicker and thorough bleed.

Attach the clutch banjo fitting/hose with the new sealing washers included in the kit. Don't over tighten.

I then installed the new CJ Designs clutch master cylinder reservoir extension. This triples the clutch fluid capacity, making it much easier to service.

I then bled the system and installed 2.5wt fork oil (anything from 0-5 wt works fine). This handy bleeding kit is included with the Evoluzione cylinder. Bleeding is very straight forward and is expedited greatly with the extra capacity CJD reservoir.

Finally, adjust the chain for the proper slack (1/2" play midpoint in the chain when the countershaft, swingarm, and rear axle are in a straight line). Note: the Owner's Manual calls for 35mm when on the sidestand. For my bike, this was too tight. In order to get the proper slack when the chain was at its tightest, as stated in the 1st sentence of this paragraph, I get 65mm (2 1/2 ") when measured as specified in the Owner's Manual. The chain should be looser than you might think, especially if you're used to street bikes. Running a chain too tight is a sure way to ruin it and possibly the transmission and chain sprockets. The best way to know if you have the proper slack is to compress the rear shock until the components meet the above requirements. Here's a link to an article that describes the procedure with photos: "Adjusting My Chain" (Photo by KevinInYorks)

Putting the spanner in the chain as shown is an old trick used to pull the axles up tight against the adjusters. Not necessary with the ZipTy kit, but I thought I'd throw it in here for the "stockers." Then put 110 nm (90nm on 05 and later) of torque on the axle nut and you're good to go.

Once you've set the proper slack in the chain via the shock compression technique, its a good idea to take a measurement with something you'll have along on each ride. This way you can check/adjust your chain on the trail without having to find a couple of big blokes to sit on your bike each time. Note: Check this measurement at several places along the chain (especially as the chain wears), and adjust to the tightest point. Also, don't go by my three fingers measurement on your bike, Each bike is a little different, as are the fingers. Develop your own.

A final check of the swingarm to axle distance assures that the front and rear sprockets are aligned perfectly. The tool I use here is a KTM Hard Parts item. It fits the ADV perfectly. P/N 58310025000. $28 from On the trail, you can get pretty close by sighting up the chain from the rear to the front striving for a straight run for the full length. Also, if you need to re tighten the rear axle nut on the trail, just stand on the spanner with extension handle from the kit. Keep an eye on it until you can torque it back at the shop.

There's nothing like a fresh chain to make a bike feel new again. I like the 16T front with the 45T rear on the backroads I ride most of the time around my home in the Pacific Northwest woods. I stick the 17T on with the 45T rear for those long trips on the slab, but carry the 16T for when I get to the "good stuff." There is an increase in engine RPMs of ~300 at 75 MPH (125 kph) for each tooth less on the front sprocket or 3 teeth more on the rear.
Also, I really like the ZipTy chain adjustors (thanks ABYSS). They keep the adjuster with the swingarm when you pull the axle and make tire changes a breeze. And what more could I say about cjracer's reservoir and Evoluzione's slave cylinder than they are top of the line in craftsmanship and quality. Craig and Ken are great folks and extremely easy to deal with. Both guys are to be commended for providing very useful products for our relatively small "niche" bike community.

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