Engine noise,

[Bb155]

When i blip the throttle i hear a rattling sound, only when the engine starts to revv or when the revvs drop.
I've replaced the kips linkages and even when i press down the kips valves i can still hear the noise.
There is no play on the crankshaft noticeable.
I hear the noise in the upper part of the engine, the bike has done 19000km and has never been opened.
I suspect a piston ring failure or piston ring gap too big?
Any other suggestions?

[500bernie]

Small end bearings

[JanBros]

I hear the noise in the upper part of the engine, the bike has done 19000km and has never been opened.
I suspect a piston ring failure or piston ring gap too big?
Any other suggestions?

19.000 and never openend ?

my suggestion would be to stop blipping and open the engine asap. change at least piston's, piston pin and small end bearring's.

[Bb155]

I was not planning riding the bike now, it's been 3 years since the bike was on the road.
Back then i heard a unknown noise, never had the time to take a look.
I owned a kr1-s in 1991 and never had any problems in those days.
At that time i never heard of middle crank pin failure.
Can i check the crank without splitting the engine?
Yesterday i renewed the kips linkages and reassembled the renovated silencers.
The inner part of the silencer came loose and made an odd noise at about 10500rpm.
I wanted to keep the original silencers so i took them apart.
I will try to post a video and some pictures to clarify this and that.