Topic: CB550 case splitting

[akabek]

Has anyone split the cases to do transmission work on a CB550 by flipping the engine upside down?  After looking at a diagram you would need to remove the primary shaft which is installed into the lower case.  I am not sure if or how you can remove the primary chain to allow the shaft to be removed.  My top end was redone so I would hate to have to tear down the entire motor and replace all my gaskets again.  Has anyone successfully split the cases this way?  Is there a trick to get the primary shaft out?

[DaveBarbier]

Don't need to tear down the motor. Primary shaft gets pulled out from the clutch side and off the chain. Can be done while cases are together. If you look up "replacing starter clutch in a 550 in frame" there is a post on how to do it while the motor is even in the frame. You access it from the oil pan. Just be aware that there are small needle bearings that may fall out when you pull the shaft. Don't want them to drop down the cam chain tunnel or anything.

What exactly do you need to service?

[akabek]

Would I better off removing the primary shaft while it is in the frame?

3rd gear slips in and out so I need to pull it apart to see what is warn.

[DaveBarbier]

Would I better off removing the primary shaft while it is in the frame?

3rd gear slips in and out so I need to pull it apart to see what is warn.

I haven't done it before but I'd think it would be easiest while it's on the bench upside down.

I was able to see my broken gear through the oil pan opening. Have you looked up there with a light to see anything? Drain the oil and look for ferrous material yet?

[akabek]

I did pulled the pan but I could find the problem.  I refilled the engine with new oil and after a short ride there is a fair amount of metal shavings in the oil when I drained it this week.  This weekend I am pulling the motor and turning it upside down to split the cases.

This is the thread outlining my issue.  I started about a month ago while jetting my carbs.  You will see two videos of the bike slipping whether riding slow or fast in 3rd gear hesitations.

http://forums.sohc4.net/index.php/topic,148658.0.html

While riding slow it is really noticeable now.  The bike will accelerate and then slip like the forks are no longer holding the gear in position.

[akabek]

A quick update but splitting the cases while having the engine upside down was reasonably easy.  I made a stand to hold the engine in position using 2x4s and threaded rod.  Removing the primary shaft was not difficult.  This thread was great to see how the primary shaft is removed.

http://forums.sohc4.net/index.php?topic=122084.0

[DaveBarbier]

Awesome. Yeah, I was trying to find that link to post for you. Glad it worked out easy enough. Seal it back up yet?

[akabek]

Awesome. Yeah, I was trying to find that link to post for you. Glad it worked out easy enough. Seal it back up yet?

I was contemplating painting the crankcase but I think i will just button it back up and install it.  I never wanted a show bike build and scratches add to the character.

The reason I split the cases was to find out why 3rd gear was slipping/hesitation.  When I split the cases I found the transmission gears and forks seemed to be fine.  What I found was that in the gear shift linkages behind the right cover the stopper arm that holds the drum, gearshift assembly shaft in position was bent outward.  Somehow this shaft kicked out.  It looks like the assembly was able to slide to the left while in 3rd.  I should have it running in a couple of nights but I have a feeling the bent stopper was not allowing 3rd gear to hold position.

In the attached picture the yellow mark is the stopper arm and the red mark is the drum, gearshift shaft.  The stopper arm was bent out (not shown in the picture) allowing the gearshift assemble shaft to slide out too far. 

Since I had purchased a spare parts engine I decided to swap most of the transmission parts as they looked to have less mileage then mine.

Hopefully I have found the problem....

[DaveBarbier]

I hear you about trying to keep a bike pristine. I can't do it, not going to try. I like the worn in look.

I'm just trying to think if the shift fork shaft slid out a bit I don't know if that would cause a shifting issue. The shift forks float on that shaft and are put into positions by the shift drum via locating dowels. Maybe someone else has an idea. I'd hate for you to button it up and still have an issue. I'd post as many pictures of the gears and shift forks as you can just in case.

[akabek]

I hear you about trying to keep a bike pristine. I can't do it, not going to try. I like the worn in look.

I'm just trying to think if the shift fork shaft slid out a bit I don't know if that would cause a shifting issue. The shift forks float on that shaft and are put into positions by the shift drum via locating dowels. Maybe someone else has an idea. I'd hate for you to button it up and still have an issue. I'd post as many pictures of the gears and shift forks as you can just in case.

Too late, the engine is buttoned up and the installation has begun.   There is still a few things to do before it is all done but a couple more nights and it should be time for a test run.  I did swap both the transmission gear sets and the shaft with the left and right forks.  The only thing I did not swap was the drum gearshift.

I would hate to pull it apart again but now that I have done it the second time will go much quicker.   

[DaveBarbier]

I hear you about trying to keep a bike pristine. I can't do it, not going to try. I like the worn in look.

I'm just trying to think if the shift fork shaft slid out a bit I don't know if that would cause a shifting issue. The shift forks float on that shaft and are put into positions by the shift drum via locating dowels. Maybe someone else has an idea. I'd hate for you to button it up and still have an issue. I'd post as many pictures of the gears and shift forks as you can just in case.

Too late, the engine is buttoned up and the installation has begun.   There is still a few things to do before it is all done but a couple more nights and it should be time for a test run.  I did swap both the transmission gear sets and the shaft with the left and right forks.  The only thing I did not swap was the drum gearshift.

I would hate to pull it apart again but now that I have done it the second time will go much quicker.

Ha, that was quick. Next is a roadside tranny swap.

[akabek]

I am hoping for a roadside plug chop.

[akabek]

Test ride this morning and 3rd gear is back in action.  Although I swapped out all the transmission parts except the gearshift drum assembly I believe the bent stopper was my issue.  Now I can finish jetting my CR26s.

[DaveBarbier]

Test ride this morning and 3rd gear is back in action.  Although I swapped out all the transmission parts except the gearshift drum assembly I believe the bent stopper was my issue.  Now I can finish jetting my CR26s.

Sweetness. Shotgun technique worked out well in this case.

[akabek]

I was pretty sure I found the problem....very happy is it working again.