Is it really bad for your bike to have janky shifts on a bike?

[James Vincero]

I'm getting better, but sometimes I have dodgy shifts. Like I won't release the clutch as smooth on an up shift or not rev matching on the way down.

Does this hurt the bike?

Is it a wear and tear thing or is it like this will mess up the transmission? What level of bad is this?

[Steve_M]

5 hours ago, James Vincero said:

I'm getting better, but sometimes I have dodgy shifts. Like I won't release the clutch as smooth on an up shift or not rev matching on the way down.

Does this hurt the bike?

Is it a wear and tear thing or is it like this will mess up the transmission? What level of bad is this?

Few of us get it right every time. An occasional fluffed gear change shouldn’t cause too much of an issue. 
 

Two of my friends own ex-riding school bikes, both used regularly, and neither seem to have reliability issues. If any bike is going to have an abused clutch / gearbox, surely it’s one of them. 

[husoi]

What will "hurt" your bike on what relates to gear shifting will be high revs while you're trying the "bite point" of the clutch causing it to be worn sooner than supposed.

Another thing to avoid is changing gear without applying the clutch. This is probably what will damage the gearbox the most.

Just not matching the revs while operating the clutch had little effect on it. It is the clutch's main purpose to smooth the rev differential so you're just using it for its purpose.

Perfection come with practice, Don't expect to be an expert during the first few years. Even more experienced riders (+20yr) will at some point have a dodgy shift