Author Topic: Rocker Arm Shaft Issue!!!  (Read 2839 times)

0 Members and 1 Guest are viewing this topic.

Findlater

  • Guest
Rocker Arm Shaft Issue!!!
« on: December 11, 2008, 07:45:29 PM »
So Im looking at my camshaft and the rocker arms. Ive got 3 of 4 Rocker arm shafts removed. The problem is one of my Rocker Arm shaft mounting bolts came about 1/2 inch out then stopped moving out. Its stuck on there really good and I couldnt just pull it out. Also, turning to put it back in also doesnt work anymore. Has anyone else had this issue? It turns freely but a little stiff the bolt just isnt moving in or out anymore.

Any Ideas? Im kinda stuck here
 :-[

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: Rocker Arm Shaft Issue!!!
« Reply #1 on: December 11, 2008, 07:55:16 PM »
So Im looking at my camshaft and the rocker arms. Ive got 3 of 4 Rocker arm shafts removed. The problem is one of my Rocker Arm shaft mounting bolts came about 1/2 inch out then stopped moving out. Its stuck on there really good and I couldnt just pull it out. Also, turning to put it back in also doesnt work anymore. Has anyone else had this issue? It turns freely but a little stiff the bolt just isnt moving in or out anymore.

Any Ideas? Im kinda stuck here
 :-[
Don't know what you've got, but if CB750, and its the center bolt we're talking about, look at end of shaft. If it has a groove cut in it, that groove should be vertical. You can turn it with a screwdriver. Some shafts had a halfmoon cut in them and if the shaft rotates the bolt will hang up coming out. Others had the groove cut all the way around the center of the shaft and rotating didn't matter in which case you need a bigger hammer. (just kidding, I don't know) Clear as mud?
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Findlater

  • Guest
Re: Rocker Arm Shaft Issue!!!
« Reply #2 on: December 11, 2008, 08:07:13 PM »
Not at all... I dont think you understand whats wrong.... of course its the one night my camera isn't here. My Rocker Arm Shaft Mounting bolt is stuck... and like REALLY stuck. So it doesnt matter what I do with the damned shaft itself nothing is going to move until I get the bolt out.... which has appeared to have stripped itself on the way out I guess? the BOLT not the shaft is rotating.... but I cant tighten or loosen the bolt at this point. So the shaft itself wont move and I cant get the rockers off. or the cam... or anything else.

« Last Edit: December 11, 2008, 08:31:17 PM by Findlater »

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: Rocker Arm Shaft Issue!!!
« Reply #3 on: December 11, 2008, 09:09:38 PM »
Not at all... I dont think you understand whats wrong.... of course its the one night my camera isn't here. My Rocker Arm Shaft Mounting bolt is stuck... and like REALLY stuck. So it doesnt matter what I do with the damned shaft itself nothing is going to move until I get the bolt out.... which has appeared to have stripped itself on the way out I guess? the BOLT not the shaft is rotating.... but I cant tighten or loosen the bolt at this point. So the shaft itself wont move and I cant get the rockers off. or the cam... or anything else.


Yup that's exactly the one I thought it was. So, we have to cover the more or less obvious thing first. You have the crank rotated so that there is no spring pressure on that shaft. In other words both rockers on that shaft must be free to click up and down?

If you look down from straight above, you'll see that bolt can't pass past the rocker shaft naturally. THere has to be a notch cut in the rocker shaft to allow that bolt to drop through. Some bikes had just a notch, others a 360 degree groove, and during running the rockershaft could rotate a little bit which is harmless while running. But upon disassmbly that notch will cause that bolt to hang up.  Do what I said before. IF your rockershaft doesn't have the slot cut in the end of it, to the left of the "stuck" circle in your picture,, then I am wrong for you. Check back.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Findlater

  • Guest
Re: Rocker Arm Shaft Issue!!!
« Reply #4 on: December 12, 2008, 08:01:35 AM »
Okay, I'll have a look at that tonight, I think their may be some pressure on one of the rockers, but according to the manual I was supposed to set it like this for timing? Also, My shafts have the groove that circles the whole way around the bolt so Im not sure if thats the issue at all. Anyways I'll take the pressure of the rocker and see if that helps.
Thanks.  :-[

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: Rocker Arm Shaft Issue!!!
« Reply #5 on: December 12, 2008, 08:46:12 AM »
Okay, I'll have a look at that tonight, I think their may be some pressure on one of the rockers, but according to the manual I was supposed to set it like this for timing? Also, My shafts have the groove that circles the whole way around the bolt so Im not sure if thats the issue at all. Anyways I'll take the pressure of the rocker and see if that helps.
Thanks.  :-[
I wouldn't look at the setting relative to timing, though it may coincide. I would concentrate on setting it where there is NO spring pressure on the shaft. Since you have the grooved shafts, my idea that it was the notch hanging you up isn'tright. But virtually any spring pressure on that shaft will make it hard to remove.  addressing the problem of the bolt, the shaft may have slid side to side, pressing on the bolt, then pinned in place by the spring pressure.

It may sound like I'm stretching here, but there is just not much it could be. Once you're sure there is no spring pressure, you may tap on either end of the shaft as it will move slightly side to side and let go of the bolt.

Good luck!
« Last Edit: December 12, 2008, 08:57:22 AM by MCRider »
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Findlater

  • Guest
Re: Rocker Arm Shaft Issue!!!
« Reply #6 on: December 12, 2008, 03:47:53 PM »
Well its out! :D It had nothing to do with spring or shaft pressure. I think this Engine has been apart before as I've noticed some interesting things and Im not too far into the engine tear down but clearly the bolt was kinda jammed in there in the first place and looking at the threads Im surpised I got it out as far as I did before I just had to start pulling as hard as I could with some plyers. I got it unstuck but Im a little worried now about putting it back in- well that bolt clearly isnt going back in but I doubt a new one will work out very well.  :-\

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: Rocker Arm Shaft Issue!!!
« Reply #7 on: December 12, 2008, 04:03:39 PM »
Well its out! :D It had nothing to do with spring or shaft pressure. I think this Engine has been apart before as I've noticed some interesting things and Im not too far into the engine tear down but clearly the bolt was kinda jammed in there in the first place and looking at the threads Im surpised I got it out as far as I did before I just had to start pulling as hard as I could with some plyers. I got it unstuck but Im a little worried now about putting it back in- well that bolt clearly isnt going back in but I doubt a new one will work out very well.  :-\

Good news!  If its been apart before... when the threads in the head would be stripped out, it was a common shadetree mechanic fix to force in a 1/4:20 SAE bolt, slightly larger than the 6mm stockers. They would interefere with the rocker shafts, but would do the job...once.

If that's the case you may need to fix the threads with a HeliCoil or HeliSert thread repair kit.  Otherwise you're on your own.
 :D
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."