Ok, from valve lifter holder to engine damage 😉
It was not my engine before but it is very likely that the previous owner has adjusted the valve clearance. Well, that’s fine but the valve cover is removed.
While doing this service work it is tempting to adjust the cam chain tensioner as well (which is a fatal error!). While the cover is off you can see how the chain get tensioned, you can feel it.
Being happy to have all that done, the valve cover is mounted again. In the top middle there is a cam chain guide that presses the chain down. You can’t set the cover by hand to sit on the sealing surface. Ok, grab the bunch of M6 screws and bolt the cover down. That works but the cam chain is tensioned by far to much.
You can even feel that the engine doesn’t crank over smoothly. Force is needed to crank it. Riding the bike in that condition is a very bad idea and will force the cam chain to break. As it still is in movement and the crankshaft is turning, the chain gets jammed in the crankcase and it breaks the case.
Except from the gear drive the engine is damaged completely:
– The tensioner of the balancer chain broke off and the balancer chain broke too.
– A piece of the engine case got a hole
– some teeth at the crankshaft – to drive the cam chain – broke off
It is very likely that this little error in sequence could be avoided by following the right sequence.
Only tension the cam chain tensioner while the valve cover is in place !
The spectakular pics were made after the damage happened and the engine was turned upside down to remove the oil pan. That causes all the loose parts to fall back to the crankcase instead of lying in the oil pan.
Here some more pics:
