Slack somewhere in drivetrain 1100 shaft

82 1100 Spectre 18k miles

I’ve only ridden the bike for about a week, but there seems to be so much play in the drivetrain. On/off throttle gives a good jolt, and I’ve never felt a bike that had this much slack in it.

I have removed the front bevel gears, the driveshaft, and the final drive gear case because I’m replacing gaskets and seals in all of them. There is very, very little play in any of them and absolutely no play in the driveshaft U-joints. Everything looks very good in there. Swing arm is tight. The rubber cush drive in the rear wheel feels good and tight as well.

If the entire drive line outside of the engine output shaft is that tight, then where is all the slack coming from? The transmission?
 

There is a "backlash" spec in the manual for the bevel gears (which can be adjusted with shims) If the jolt isn't the bevel gears next point to check would be the clutch basket

Wookie58 wrote:

There is a "backlash" spec in the manual for the bevel gears (which can be adjusted with shims) If the jolt isn't the bevel gears next point to check would be the clutch basket
 

Yes, the front bevel gears feel very tight. What little slack they have is completely disproportionate to what I’m feeling when I ride the bike. I just saw the clutch basket when I replaced the gasket for the cover. I didn’t spend too much time looking at it, but it appeared to be OK and the clutch feel is very good. Anything in particular that I’m looking for?

Legionnaire1856 wrote:

Wookie58 wrote:

There is a "backlash" spec in the manual for the bevel gears (which can be adjusted with shims) If the jolt isn't the bevel gears next point to check would be the clutch basket

 

Yes, the front bevel gears feel very tight. What little slack they have is completely disproportionate to what I’m feeling when I ride the bike. I just saw the clutch basket when I replaced the gasket for the cover. I didn’t spend too much time looking at it, but it appeared to be OK and the clutch feel is very good. Anything in particular that I’m looking for?

With the clutch plates removed you are looking for play between the clutch basket and the flywheel (they are riveted together) also check the springs in the flywheel aren't broken

Verify the "cush drive" rear wheel hub damper condition is good.

😃

daveo wrote:

Verify the "cush drive" rear wheel hub damper condition is good.

😃

You know, I totally forgot to put that in my post. I’ll see if I can add it to the original post. I have taken the wheel off and the Cush drive seems to be nice and tight with no play. It was the first thing I went to. It seems like all the play is occurring before the front bevel gears. Somehow in the transmission?

i’m not sure if these bikes are known for having a bunch of play, I’m hoping it’s not just a characteristic of the bike.

As mentioned previously, the clutch basket is the only thing before the front bevel gears that isn't a direct gear drive (transmission, primary drive etc)

Motorcycle print media in the day would often comment on driveline slack, sometimes called 'snatch' IIRC, or lack thereof, in review articles.  It may well be cumulative play in the dogs plus other trans components.

   This will require an assistant:
   If there's any way at all to observe the driveshaft when installed, place the bike on the centerstand, place the trans in 1st. gear, gently apply the rear brake while rotating the rear wheel in both directions from stop to stop.  Make sure the driveshaft moves the same instant as the rear wheel.  The rear brake applied should reveal play in the cush drive. to eliminate that variable.  Lash in the rear hub bevel gears is unlikely to be an issue unless factory shims have been molested.
   Now, release the brake and  measure the distance traveled at the tread surface from stop to stop when in 1st. gear.  Then repeat for 2nd. through 5th.  Seems logical that if the rotation distance of the rear is the same for every gear, the slack would be in the clutch basket.  If it varies for each gear, it makes sense the play would be in the dogs of each gear.
   This logic could be wrong,  but for experience observing and testing the behavior of our Honda ST1300 shaftie.  Driveline slack is slightly but noticeably different gear to gear.

Good Ridin'
slmjim & Z1BEBE

Today I measured the front to back (slack) travel distance of my KZ1100 Shaftie while parked in 1st. gear...



Total travel 3.25"

😃
 

Wookie58 wrote:

Legionnaire1856 wrote:

Wookie58 wrote:

There is a "backlash" spec in the manual for the bevel gears (which can be adjusted with shims) If the jolt isn't the bevel gears next point to check would be the clutch basket



 

Yes, the front bevel gears feel very tight. What little slack they have is completely disproportionate to what I’m feeling when I ride the bike. I just saw the clutch basket when I replaced the gasket for the cover. I didn’t spend too much time looking at it, but it appeared to be OK and the clutch feel is very good. Anything in particular that I’m looking for?

With the clutch plates removed you are looking for play between the clutch basket and the flywheel (they are riveted together) also check the springs in the flywheel aren't broken

The slack has disappeared. I have absolutely no idea what was causing it or how I fixed it, but it’s as tight as new. 

I removed the front bevel gears, the final drive, prop shaft and swing arm to fix some leaky oil seals and gaskets. I did remove and repack the tapered roller bearings on the swing arm and set the clearance and torqued it correctly. I cleaned and regreased the driveshaft slip joint splines and put fresh 90w oil in the final drive. I replaced every seal in the final drive and almost every seal in the front bevel gears. 

The swing arm was tight before I removed it. The bevel gears and final drive were tight. Unless something wasn’t engaged properly from the last bozo that was digging around in there, I don’t know what I could have done to fix it. But it’s like new and I’m happy. There was a lot of slack in the driveline, I can’t think of how something would be that far off. The stuff only fits in there one way. 

Edit: I believe now that it was a severely mis-adjusted clutch. I had to remove the clutch adjustment screw locknut on the front bevel gears to remove the clutch cable when I took the bevel gears off the bike. The previous owner(s) has done a lot of sub-par work on the bike, and they had burred up the end of the adjustment screw once upon a time. So when I went to remove the locknut, it hung on the screw end and turned the screw all over the place, forcing me to adjust the clutch when I put it all back together. That must have done the trick.