Chain question..

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#1
Either im REALLY bad at using the search function, or there really aren't any links in the search function relating to my question(I doubt it). On my 99 300 MXC, from the back of the black chain slider thingy on top of the swingarm how much play am I supposed to have in my chain?

I asked this on the KTM forum becuase I know that KTM's are one of the few bikes with the linkless rear suspension and I know this has something to do with chain slack.......i think...........hope...:D

KaTMandoo
 

Bonehead

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#2
Chain Question

OK. I run my chain looser than all the guyes I ride with
Man I hope you got the book that came with your bike

If you are an old honda rider you will remember that they had a chain slide that was 2" above the top of the swingarm .

that was where honda wanted you to run the slack at (the top of the slide)

KTM wants you to have 15mm between the chain and the swingarm from the bottom of the swingarm. that is only about 1.5" of top slack. I have found that is not enough . I run from 2'' to 2.5" of top slack

I started with my ktm's going from the book
I lost the weel bearingh after 10 rides (only on the drive side)
After changing to 2" top slack no proublems
 
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#3
you say from the bottom of the swingarm, which section of the bottom or does it matter?

KaTMandoo
 
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#4
Pull the chain up on the top of the swingarm at the rear of the buffer. Set the slack for approx 2.5", or 3 average size fingers between the chain and arm. Verify this next time you have the shock off, move the arm to the chains tightest point and check for adequate slack there. Leave slightly more slack for really muddy conditions.
 

Jaybird

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#5
Katmando,
You want your bike to be on the ground. Best if you have someone on it. At the bottom of the swing arm where the chain exits the guide, you want to push the chain upward towards the swing arm. Only one links distance from the end of the guide. You want to have a measurment of approx. 5/8" from the top of the link (link paralel to swing arm) to the bottom of the swing arm.
Don't use the two or three finger method, thats for 'blue bikers' only :p
This tension will NOT cause a bearing to fail. Bonehead had another problem, I'm sure. It is VERY important that you have the axle perpendicular to the chain travel. In other words, if you dont have both sides of your adjusters exactly the same distance, you run a chance of damaging something else...ie: a wheel bearing.
Bonehead, if you are the only one that runs their chain that loose, does that tell you anything?
 
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#6
No offense jaybird, but i think bonehead is closer to correct. I did the factory method several times and took the shock off to varify, and it was always a little to tight. I since have come up with my own method: the bottom of the chain just touches the top of the rear chain guide. I first took the shock off and got a taught chain at worst case (swingarm level) and then found a measurement devise best for me. Oh yeah, i use a freddette rear guide. hope this helps. my original chain has over 50hrs on it, origianl rear sprocket, one new front sprocket so far, and about 6 enduro's.
 
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#7
Jaybird,

Thats why I said VERIFY adequate slack with the shock off. This is true for any bike. Do this once (as Chris has also) and you get a feel for what you need to see on the stand, no matter how you measure it. My '99 300 EXC went over 1100mi on a chain, and it was still good.

KTM wheel bearing failures are mostly from the soft aluminum spacers that groove in a few rides and let crud in.
 
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#8
ok thx guys, Jaybird.....your explanation was just a little bit confusing, although it sounds professional, hehe.

KaTMandoo
 

Bonehead

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#9
Thanks for the back up . Chriis NJ

O.K. sit on the bike and if the chain is tight it is to tight!!!
I always check the axle alignment by measuring tape ,from center to center (axle to swingarm) My 97 XR400 was 3 marks off on the left side


OO 520 EXC
OO 380 EXC
 

Jaybird

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#10
You want your bike to be on the ground. Best if you have someone on it.
Maybe I should have said, "best to have swing arm parallel to the ground."

Only point I want to make is, if you follow this tensioning method it will not cause a wheel bearing to go. Nor will it be too tight.