Chain tension

R6mick · **Joined:** Sun Mar 27, 2011 6:47 pm **Posts:** 38

I've read in other threads that trail bikes chains should be quite slack.
I've been adjusting bike chains for years but only recently started trail riding. I have a ktm exc 300 and the hand book says 15mm of play in the lower chain when the bike is standing with on rider. I adjusted to suit this but looks way too tight to me.

steviefd · **Joined:** Tue Mar 08, 2011 9:25 pm **Posts:** 13

I'm no expert but if you still have that much play with your full weight on it then it doesnt sound too tight. Try it, you can often hear if a chain is too tight by hearing a 'humming' sound.

scotsy · **Joined:** Fri Oct 30, 2009 10:57 pm **Posts:** 356

When i had a 250 ktm i got ribbed about my chain being 'too tight' like yours

On www.ktmforum.co.uk there is a bloke called 'kevinyorks' who seems pretty clued up with ktm's and he advised me to push the chain upwards from underneath the swingarm (just behind the back edge of the swingarm protector and the chain should almost touch the underside of the swingarm. If you run it too tight it will knacker the seal behind the front sprocket (and maybe the bearing)

R6mick · **Joined:** Sun Mar 27, 2011 6:47 pm **Posts:** 38

Sorry, typo on original thread. I meant 15mm of play with bike standing with no rider, not "on rider".
Good advice though, I'll slacken it of a bit

Gooders · **Posted:** Sat Apr 30, 2011 9:00 pm

Just make sure there is still a small amount of slack when you are sat on the bike. The swing arm goes through a large arc due to the suspension travel unlike a sports/road bike. Too tight and you will wear the chain in no time, too slack and you risk it hopping off the sprockets.

jonpaul1st · **Posted:** Sat Apr 30, 2011 9:57 pm

scotsy wrote:

When i had a 250 ktm i got ribbed about my chain being 'too tight' like yours

On http://www.ktmforum.co.uk there is a bloke called 'kevinyorks' who seems pretty clued up with ktm's and he advised me to push the chain upwards from underneath the swingarm (just behind the back edge of the swingarm protector and the chain should almost touch the underside of the swingarm. If you run it too tight it will knacker the seal behind the front sprocket (and maybe the bearing)

Apologies if I'm stating stuff you already know.....

If you put some bolts in the holes in the swingarm. where the chainguard is fixed, it stops water getting in and corroding the swingarm from the inside.

scotsy · **Joined:** Fri Oct 30, 2009 10:57 pm **Posts:** 356

jonpaul1st wrote:

scotsy wrote:

Apologies if I'm stating stuff you already know.....

If you put some bolts in the holes in the swingarm. where the chainguard is fixed, it stops water getting in and corroding the swingarm from the inside.

Good advice but.............

The Orange beastie is long gone, i've been a Honda fan all my life and i'm back where i belong due to ........

jonpaul1st · **Posted:** Sat Apr 30, 2011 11:45 pm

I had a Honda - best step thru's ever made

Rougharse-Racing · **Joined:** Sun Oct 31, 2010 1:54 pm **Posts:** 82

Fit a chain tensioner and you will never have to worry about slack chains again.
If your chain is too tight you will knacker the wheel bearing on the sprocket side, and possibly also the bearing beside the gearbox sprocket. Get a fat mate to sit on the bike to compress the suspension and if it is as taught as a piano wire on full travel then it is too tight.

Dave74 · **Posted:** Sun May 01, 2011 3:09 pm

the sticker on the swing arm of my 450 exc says 8-10 mm of slack
is this meant to be with the suspension compressed or not i would have thought it is without as it is easier to check

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Chain tension

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