'77 KZ650 Shifting Problems

I've been trying to diagnose this problem all summer. The shifting on my 2015 Vulcan S is click click easy peasy.
The shifting on my KZ650 started out more of a clunk clunk. Very heavy shifting but also 40 years older. Over the summer it got worse and when shifting up and down the clunk was accompanied by a metallic clunk just as the clutch engages. Seems worse from neutral to 3rd. 
With the bike on the center stand, rocking the back wheel back and forth in any gear, all seems normal tight and quiet. 
I re adjusted the clutch.
I changed the oil.
Clutch release mechanism, removed, cleaned and re-lubricated. Nothing has changed on it since the bikes restoration.Clutch readjusted to give maximum throw.Still clunks and hard to shift
Found too much play in the clutch basket
Clutch basket removed, rivets machined off, new rubber dampers purchased from UK installed, backing plate welded on, clutch re installed.
Clutch readjusted to give maximum throw.

Still hard to shift. Still clunks (metal on metal) when letting clutch out most of the time unless I am shifting at over 6000 rpm. Then it seems to shift smoothly.

Could my problem be a shifting drum issue???

As well as the clutch basket there are "cush drive" rubbers between the starter clutch and 1st motion shaft (not an easy job to access !!!)

I suspect the clutch plates are slightly warped, causing drag when running.  I've experienced this issue on different bikes before, and replacing the friction and metal clutch plates fixed the problem.

Also, make sure your shift shaft hasn't damaged the side cover or transmission cover.  If the shaft wollows around it makes the shifting impercise.  

I put a completely different set of clutch plates and friction plates in when I changed the basket dampers. Exact same problem.

Wookie58 wrote:

As well as the clutch basket there are "cush drive" rubbers between the starter clutch and 1st motion shaft (not an easy job to access !!!)

 

With the bike on the center stand, in gear, I can rock the wheel back and forth and get none of the clunking. I'm now leaning towards the shifter assembly?

Did you check the shift forks? they can end up getting bent/warped over time. Its unusual but it does happen, more often from abuse like drag race quick shifting or air shifter use (more pressure on fork ends)

I have have owned and worked on a lot of KZ650's and the only time I ever had a shifting issue was on a drag bike.

The only other "clunking" I ever had was worn out clutch hub rubbers. Like previously mentioned the trans cover bushings can get sloppy over time causing binding.

Injected wrote:

Did you check the shift forks? they can end up getting bent/warped over time. Its unusual but it does happen, more often from abuse like drag race quick shifting or air shifter use (more pressure on fork ends)

I have have owned and worked on a lot of KZ650's and the only time I ever had a shifting issue was on a drag bike.

The only other "clunking" I ever had was worn out clutch hub rubbers. Like previously mentioned the trans cover bushings can get sloppy over time causing binding.

 

I restored the bike 3 years ago. Shifter forks were good then, bike shifted good for the first year + but has progressively got worse. I've only driven it about 1500 km. Never abused. 
I haven't yet opened up the crankcase as that will be my last resort. Can you change the shift forks from underneath without pulling the engine?

You said the clunk occurs when letting the clutch out ? By this point the shifting is done and what is happening is a load change between the primary drive and the transmission?

That's what I first thought at first but I tried to duplicate the clunk with the engine off and rock the back wheel back and forth. It doesn't. Is it possible the shifter detent is only half shifting and then as I let the clutch out it slams into the next gear?

I guess its possible but don’t forget when the engine is off there is no load on the primary drive

wrote:

wrote:

Did you check the shift forks? they can end up getting bent/warped over time. Its unusual but it does happen, more often from abuse like drag race quick shifting or air shifter use (more pressure on fork ends)

I have have owned and worked on a lot of KZ650's and the only time I ever had a shifting issue was on a drag bike.

The only other "clunking" I ever had was worn out clutch hub rubbers. Like previously mentioned the trans cover bushings can get sloppy over time causing binding.


 

Can you change the shift forks from underneath without pulling the engine?


 

No you can't do that on a 650/750 as the oil filter housing casting is in the way. No way to drop the forks down.

 

 

On the Z1 you can do it with some mods, drag bike guys do it all the time at the track. On the Z1 the shift drum/forks are clear of the oil filter housing casting.

The 650/750 engines rarely suffer from shifting malfunctions unless something is reassembled wrong or a part is extremely worn out.

Never ever seen a shifter drum issue, mostly shifter fork end wear or shift shaft mechanism issues (binding) Its very easy to check the shifter mechanism on the bike if you haven't already confirmed it.

If this happened after a rebuild and it was working OK then, it has to be wear related. Something may have looked OK but was on its way out.