Feb 2, 2001
The manual suggests .6Inches between the top of the chain and the swingarm. Before riding the other day i check this and all was well. after about 20 minuits the chain was so tight the wheel would barely spin. some dirt had gotten in the chain.

How loose / tight should the chain really be?

Also what is the best way to clean the chain and lube the chain? is chain wax good?

I have to buy a wrench for the big nut holding the back wheel on... what size is this on the 400mxc?

Sorry for all the newbie questions.


Jul 21, 1999
Make sure you measure the chain slack with the bike off the stand and maybe even compress the suspension a bit.

27mm nut on both axles. You should have a wrench in your KTM supplied toolkit that will work for that but you'll need a socket to torque them.

I wash my chain with the graden hose and maybe a nylon bristle brush if it's really dirty. Just put it on a stand and rotate the wheel while hosing it down. DO NOT do this with a high pressure washer, though. I use chain wax on all of our chains and it works great.

John Brunsgaard - JEB
01 KTM 400 EXC
99 KTM 250 EXC
99 KTM 200 EXC
98 KTM 125 EXC
98 KTM 380 MXC (gone)
96 KDX 200


Nov 20, 2000
Do yourself a favor and remove the tank. Then the shock will come out by removing the two mount bolts. With shock out hook a tiedown over the seat to the swingarm and pull it up until the rear axle, the swingarm pivot bolt and the countershaft sprocket are all in a straight line. This is the tightest place for the chain. Adjust it with a 1/2 to 1 inch of freeplay at this point. Now reassemble every thing and look at the adjustment. Find a reference mark you can remember and use this for the tightest point in the future. It will be a lot looser than you think it should be. Better to err too loose than too tight. Tight chains destroy wheel bearings, sprockets and sprocket bolts, rear hubs, transmission bearings and even engine cases.


01 KTM 520EXC
97 KTM 620RXC
98 BMWR1100RT


Dec 10, 2000
HGilliam is right. I adjust my chain similar to the way he describes. The resulting slack is quite loose when the bike is on a stand or kickstand. Regarding the owner's manual illustration, my adjustment method yielded about 11 mm of space bewteen the chain and swingarm at the bottom rear end of the chain buffer. This is with the bike on the kickstand as shown in the owner's manual. I agree with HGilliam, better a little loose than too tight.

I have used Maxima Chain Wax for years and it seems to work well. I always get a full year of muddy riding out of my chain and sprockets (it is always muddy here). I do not do any thing special to the chain and I do powerwash my bikes. I believe the chain wax provides an additional barrier on the chain o-rings, which in turn helps to preserve the grease built into the chain. I like that the wax dries and is not greasy when handling the chain. My kids would forever have greasy chain prints on their hands if I was using a oily or sticky lube.

Can't wait to ride my bike,


'01 KTM 400 EXC
'95 KTM 300 EXC (sold)
'89 Kick Ten Minutes 600 LC4 (too much bike for the woods)

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