Stiff gearbox?

Hi Guys

I have a slight problem with my bike, the gear selector gets really stiff to operate. This doesnt seem to apply when starting off from cold and isnt stiff all the time. It comes and goes as i ride, can be fine then within a few shifts as stiff as fook. A few more minutes/shifts and things go back to normal. This can happen a couple of times on a ride or not at all. Weird.

Now I did embarrassingly drop my bike on the local petrol stn forecourt and bent the relay lever, this was replaced and the shifter doesnt seem sticky or stiff. I"ve changed the oil? but hasnt made a difference, it needed doing anyway. I'm at a loss as to what to do especially as its so intermittent.

Has anybody got any ideas or had a similar problem, any help would be much appreciated.

Work with the linkage first before going into the engine.
Remove the linkage and see if you can see any thing bent / rubbing or out of true with the pivot rods.

You might have bent the shift rod that goes into the engine.

I bent my KTM 300 EXC shifter rod that goes into the engine when I had to drag my bike across a down timber.

It hangs up from time to time, kind of random.

A ham fisted mechanic would be tempted to place a snug fitting pipe over the said shaft and giving it a tug in the correct direction.