Right, need some expert advice here from people that have reassembled gearboxes, and fixed problems.

My bike has always had problems shifting gear, usually 3-4th, but it was occasionally tempramental in other gears.

After sorting out the shift spindle play issue, put the clutch and case back together. Once the gear change lever and clutch cable were connected, I checked the shifting. Didn't feel right at all. So, pulled the cover off, disassembled the clutch. When looking at the shift mechanism with the clutch out, and using the gear change lever I can the star shaped centre shift drum to click through and rotate about three times, after that it won't move any further. Is this correct?

Looking at the star shaped centre shift drum, what position should it be in for neutral? How should it be facing relative to the stopper (part 8 on the F6 parts diagram)?

I noticed the stopper arm spring had been pinched between the retaining plate and the cases whenever i was last installed. Maybe this has caused it to warp or create a binding in the mechanism. I have swapped out the whole cassette for a spare that I had and installed it as per the manual. Have yet to check the operation, and it will be a week until the new clutch cover gasket arrives.

Should I be looking further into the gearbox for other signs af damage ie shift forks, or any other specific areas? I'll have to check the retaining plate to see if it is out of true before reusing this unit.

Is there any chance to getting a gearbox assembly/inspection section added to theworkshop to go with the engine reassembly? Took me about three goes to get it right as I was working from a Japanese book.

Really appreciate some guidance here.

Send me a PM and i'll give you my number, i've pulled apart a few gearboxes in NC29's and things, and have an MC21 gearbox on the workbench if you want to compare.

I'm not an expert, but over the years have had a couple of dramas with gearboxes that taught me a thing or two to look for relating to damage.

There are a couple of relatively simple things to look for, but unless you know what they are you might miss them. Look for bluing of the gears and the ends of the selector forks, rounded engagement dogs, and you also need to remove the selector shaft the forks are on and check it is still straight. Any damage to those and you can have difficulty changing, and the damage does not even need to look significant to cause a shifting issue in something rotating a few thousand times a minute.

Thanks Greggo. I'll pm you later today.