Topic: wont shift to gear higher than 2cd

[KRONUS0100]

my 72 cb750..just finished the rebuild............had it on center stand burning oil out of cylinders and breaking in the rings...........it wont shift up to 3rd gear...first and second only..  I remember reading here someone else had this problem.......cant find the thread.  thinking it may be an upside down center shift fork......anyone remmber this article?  also....on the shift linkage......does the big roller wheel go behind the tar mechanism or does it go in same groove as the long shift arm goes into?    thanks.

[KRONUS0100]

update.....took it out tore it down.........middle shift fork was upside down.......2 of the little pins in end of shift drum were in wrong places...fixed that....double checked outside linkage when went back together...still no 3rd gear , 4th gear or 5th gear shifts...any more ideas?

[mystic_1]

2 of the little pins in end of shift drum were in wrong places...fixed that

Hmm, tell us more about this part?  It's pretty hard to get those pins into the wrong places, one is shorter than the others and the holes in the plates should dictate what goes where.

Got pics?


When you TRY to shift up into third, what actually happens?  Can you not lift the lever, or does it go up but leave you in 2nd, or does it go up and leave you in a false neutral?


Take the shifter cover off, put the shift lever back onto the shift shaft, and then operate the mechanism as you roll the back tire.  Watch the shift pawl arm, see how it ratchets over the pins as you lift and then release the lever.  When you reach the upshift to third, what happens?

If the shift mechanism is doing it's job, then you have an internal problem and need to split the cases again.  Perhaps you missed getting the center fork aligned with the secondary shaft gear when putting hte cases back together?

mystic_1

[KRONUS0100]

update.   brother in law came over and had a look at it.  We came to conclusion that the real big "A" shaped spring that goes over the shift drum itself was in wrong place.....no real good pictures of where it goes in any of the books...so he moved it where he thought...and double checked the shift arm to cover clearance....and now it all works like it should.  I took it down the road and put 10 miles on it....So now..how many miles should I put on it to break in the rings and change the oil?