Topic: 1976 cb750 f1 no 5th gear

[750steve]

after sitting in the back of the garage for 6 years or more i decided to put the old girl back on the road...i had been starting the bike regularly but not actually riding it.i fitted new plugs air/oil filters and changed the oil but find that i can/t get 5th gear...1 to 4 are fine but 5th just won/t go in.can anybody suggest what the problem may be...it was running fine last time out on the road but that was a fair while ago...if anyone recognises the problem....what would the solution be....tnx a lot...fantastic site here guys...great tips...tnx...steve.

[bryanj]

Not wanting to cast doubt but are you sure it was OK when you parked it and that wasnt the reason?
2nd and/or 5th were the gears that gave trouble if any did and usually came out as selector drum, selectors and gears

[RHARVEY]

I also have the same problem with 5th gear having seemingly disappeared! My bike is a 1977 cb750k, when shifting throught the pattern theres no grinding, no out of the ordinary noise coming from the transmission. As soon as i try to shift between 4th & 5th its like 5th doesn't exist. No false neutral i just remain in 4th gear. Is there some sort of adjustment in the shifter mechanism i'm missing that can correct this problem? I have a clymer manual, however i find it so vague on the matter it doesn't help me. Any help on this matter would be greatly appreciated. R.H.

[Bodi]

You would have to open the side cover to see the mechanism. It's pretty self explanatory once you see it, the shifter lever moves a fork that hits pins on the shift drum end. That ritates the drum, there's a spring loaded roller that engages notches in the drum to hold it at the right rotation for each gear.
There may be some problem with the outer fork or the 5th pin may have even fallen out of the drum.
If the fork is hitting the 5th gear pin but the drum won't turn then there's something stuck in the transmission, a gear frozen on a shaft maybe. If the drum turns but you get no 5th, the shifter forks inside that move the gears may be bent or the drum itself is worn out. But with those drum I would expect a false neutral rather than staying in 4th.

[RHARVEY]

I have taken the side cover off the engine to look at it. It looks like all the pins are there according to the parts manual i have, six in total. Watching the drum turn however, when you shift up from 4th to 5th you notice the last pin stopping a hair short of engagement. That's why i asked whether or not there's some sort of quick fix without opening her up?

[bryanj]

Not really, If the drum stops rotating anf you cant finish the movement manualy as it were, then there has to be a physical interl fault, Maybe bent selector stopping the rotation