K75 engine knock

[curtisb]

Hi all
I'm new to this forum, I have a 85 K75C which I've had about 18 mouths it was running like a watch even the mechanic at the last MOT commented how sweet it sounded, but on the way home some idiot pulled out in front of me causing me to brake hard ad I stalled restarted motor and it was knock its head off.
have stripped top and bottom covers no obvious problem bear seam fine mains and small cams look good no play etc, did find a small piece of metal turned out to be a broken sprag spring replaced with new and washed motor out new filter oil etc, but knock still there, vale time is correct valve clearance look to be OK, alternator rubber fine ( knock still there with alternator out ) don't thinks gear box as knock is still there with the clutch pulled in. Please please help I'm at a loss now any ideas welcome many thanks. am lost without K75  ???

[mystic red]

( knock still there with alternator out )

I was going this direction until I read that it still knocks with the alternator out?
And you think it had something to do with the hard brake and engine kill?

[merlin geikie]

Maybe you could explain the noise a little?

Is it road speed dependant or rpm dependant?

You had work done on the sprag clutch, did this involve a full pulldown?

Keep at it ;)

[curtisb]

It increases with engine rev's haven't driven the bike since it started knocking.

I stripped the engine down topand bottom cover off removed gearbox and cluch to find sprag spring damged removed cogg assemlies and checked for any damage all looked ok reassembled with replacement sprag spring but knock still there, also washed out engine to ensure no bi left behind.

[ned37]

few years back i had a bike that lost a cam bearing retainer. after an engine flush and putting it back together i had a knock.  pulled it back down and found a small piece of the retainer shrapnel had gotten wedged in the teeth of the clutch/ drive gear pried it out and all was ok.  perhaps a piece of your sprague did the same?