hi

i have a 2006 xt660r its done 14000 miles and its started to clunk when i put in gear.

i have looked at it and found that there is about 10mm plus backlash on the small chain

sprocket.

could this be down to the clutch basket starting to wear due to running in to high a gear

at low revs or is it a common problem with big singles

what other things should i check

sounds like clutch drag. adjust the clutch if its cable operated (and not at the lever end) also I find it helps if the chain is adjuted correctly too

can you describe this 10mm backlash in more detail mike, are you rocking the bike in gear with the engine off to see this?

Yes, a little more detail please...

Is this 'backlash', through the whole drive chain ? have you looked at the freeplay at the rear wheel ?

At 14k the Cush rubbers will be a melted lump of goo, so if you've never changed them this would account for free play between the wheel and the sproket. Just chucking in some possibilities, it could be anything from your description.

Also, if the chain is loose these bikes clunk loudly when you put them into gear.

There have been occasions when the internals have self destructed, but these are very rare, so I'd check the easy stuff first.

Hi Yeah i have a 2007 bought new, gear box was pretty agricutural then.

Have done 36000, fitted 4 sets of cush rubbers, if anything gear box has improved, provided it has plenty of good clean oil?

Change the clutch cable, probably has rust. And this happens when the chain is very tight, at least in my XT600. I found a Latin American solution for the clonks/clanks: now I use a semi syntethic 15W50 oil and dissappeared! Remember to use the clutch several times when you start the engine and when you are waiting to ride it, it's very useful and that make the clutch be lubricated with the engine oil.