Motorcycle Repair: gear problem, 1982 honda cm450, worst case scenario

Question
Purchased a 1982 Honda CM450 that has been in storage since 1992. Everything is perfect with only 7000 miles but have a symptom of gears not shifting. Will go into first and second without problem but when lift up shift bar it fails to shift to third. If repeatedly lift bar or sometimes if downshift and then upshift then goes. Once in third will have same but lesser problem going to fourth and fifth. Sometimes will pop out into neutral. Thoughts?

Answer
Log into: http://www.powersportspro.com/partsfish/login.asp

and find your bike in the list. CM450, then check the gearshift drum/gearshift arm illustrations for reference.

Poor shifting can come from a clutch that isn't disengaging properly (common from a bike that has been sitting for a long time), as well as a bent shift shaft, which happens when the bike tips over and the shift lever gets forced out of position/location. While unusual, it is possible that the central bolt that holds the shift drum detent plate and pins could have backed out or the shift drum stopper/spring could have a problem or the shaft return spring may be damaged.
In the worst case scenario, some previous owner may have used the bike to "learn to ride" on and damaged the shift forks from stomping on the shifter without disengagaing the clutch.
Plan on buying a clutch cover gasket and some oil at the very least, to see what is going on with the gear selection parts. You may have to disassemble the clutch assy to access the gear selection parts. The tricky part there is getting the 20mm locknut loose. You may need some air tools to get that done. When you are in the clutch cover, check the counterbalance chain adjustment.

On some bikes, you can check the gear selection parts w/o clutch disassembly, but I haven't been into one of these machines for many years and don't have any shop manuals.
Check Ebay or www.helminc.com for manuals, which will be most helpful in cases like this.
If the gear selector parts and clutch plates are all okay, then an engine teardown will be necessary to replace the transmission parts and that is probably not a worthwhile thing to do financially...    Bill Silver