Does any wise person know exactly how a misbehaving KACR makes the horrible knocking sound ?
And second, after removing my KACR (cut it off the shaft) the starter motor is struggling to turn it over, there's no chance of a start...the starter is clean, the brushes good....
What should I be looking at please ..2009 carbed 2509T9F ..thanks

 

Well, as far as I'm aware the answer to the slow crank would be tied to the KACR(or more accurately, lack of).
It bleeds off some compression by keeping an exhaust valve open slightly.
When they fail, it usually clatters.

 

Quite a bit of searching has thrown up a number of folk who have no starting issues after disabling the kacr, which is why I removed it.
I'm very aware of the clattering, what I'd like to know is exactly how it makes the racket....if the spring fails for example the weights fling out a bit earlier than otherwise....they're designed to whizz around so broken spring won't cause the noise...if a pin comes out then there'd be more than a noise there'd be calamity.....maybe the pins can get a bit of slop and there's a bit of lateral movement ?

 

I disabled my KACR and no problem starting. Now what I'd be checking is the simplest first. Make sure the battery is at full charge. Next, try jumping from a car battery (car NOT running), it provides the necessary voltage but with more cold cranking power. Then things start coming apart. Check valve timing, the KACR will not make any clatter, even with the spring off (unless the idle is set extremely low - too low, should be around 1250 rpm.

Clatter indicates something totally different than the KACR. When it is in the bike it only will throw the shoes out at low rpm, under around 800 rpm if I remember right. Clatter has to be something else. If the noise is noticeable on the right side louder than on the left you have a cam drive issue, chain tensioner failing.

The one other clatter that could maybe affect engine turn over is the one you don't want to hear - valve timing is out of time and possibly the piston is hitting valves. Not a good thing. Verify the cam sprockets are bolted on in the correct holes properly lined up on the cams. Verify the engine is at the T mark through the small hole on the stator cover on the left side, then verify the cam timing marks are alighned parallel to the head surface when you look from the side.

I hope it's something simple. I also have a 2009 with the KACR disabled, not removed, I didn't have the time to remove it when I did the MCM cam timing mod and haven't done it yet. I also have one of my manual cam chain tensioners on the bike to take up slack after the OEM tensioner quit working. I've not had any problem, even started the bike in single digit weather, firing near instantly.

Let me know how it goes.

 

I'm suspecting something electrical. Hot or cold starts have never been a problem, I always run the carb dry if I'm not using the bike for a couple of days (long enough for the petrol volatiles to disappear from carb bowl) The starting problem now is starter motor lack of power to turn engine over. Even with a jump starter connected as well as the new lithium battery the engine is still a reluctant spinner....but once going runs just fine and MUCH quieter than previously.
(I've had the cam chain thing and have had your manual doofer fitted for a while) I think a check of connections etc is in order. Starter looks ok, clean and good brushes.

 

UPDATE...I couldn't figure out where the main earth connection is, so I added one from battery to rear frame, charged the battery...and it immediately started. I suspect battery may have been a major culprit all along. I checked the voltage when I bought it, I can't remember the reading but I thought it fine at the time, and didn't put it on a charger....I blame my aging brain (and too much faith in an aliexpress jumper) for all the drama. Thanks all for the advice. That's the 250 back on the road. I've just picked up new handlebars for the BMW after I hit a sheep three weeks ago...

 

Ah! You were holding out information on us.