5-th speed

[lonerider41life]

Hello.
Since winter is coming, I want to do a deep inspection of the motorcycle, in terms of the engine and cardan transmission. I purchased a whole set of gaskets, oil seals and o-rings, with which I want to replace the worn and aged ones, because I have oil and coolant leaks. Maybe I'll look for a thermostat. But there is another problem and I am curious if I should disassemble the engine block. Since I got the motorcycle (with no service history), I noticed that the gears sometimes change roughly and sometimes easily, but almost always the 5th gear changes in two steps (from 4 to 5), when I lift the pedal of the shifter from 4 to 5 it clicks and I have to hold it up until make another click and enter/remain in 5 speed. If I'm not paying attention or I'm in a hurry, I've had it drop back into gear 4 or get stuck between 4 and 5. From 5 to 4 is no problem. What I also noticed is that if I change all the gears, from 1 to 5, somewhere in the range of 1200-1500rpm, the box changes smoothly. Should I have a problem with this? Should I crack the engine in two and check the pinions, dogs and drum? Or it could be a problem with the clutch or the oil used. Thank you.
It is a 1989 GL1500

[Sassy]

Our 1500s are beautiful bikes but agricultural transmissions. Worst shifting bike I've ever owned in almost 60 years of riding.
I'll be interested if you split the cases as 5th can be vague at times on my '89 too.

[WingAdmin]

Our 1500s are beautiful bikes but agricultural transmissions. Worst shifting bike I've ever owned in almost 60 years of riding.
I'll be interested if you split the cases as 5th can be vague at times on my '89 too.

I suspect our agricultural tractor transmissions are due to the large torque at low RPM that the engines produce, unlike pretty much every other motorcycle.

[Sassy]

Torque isn't involved in gear changes when the clutch is disengaged.