77 GS550 Shifting/Clutch Woes

[mehall2]

I'm about at my wits end. I'm trying to troubleshoot a clutch shifting issue in my 77 GS550 which appears when the bike is fully warmed up. The symptoms are that it takes considerable more pressure on the shifter to downshift first of all. Next, when starting from a stop in first gear (this happens when I roll to a stop while in first and holding clutch in), I'll let the clutch out and hear/feel a "thunk" right before it abruptly catches. The thunk doesn't happen when I'm stopped in neutral and then shift into first. Weird, huh?

I have already installed a new clutch cable, new helical shifting actuator, new clutch plates and a new inner clutch hub sleeve. The clutch lever seems to be adjusted with the correct amount of play.

I'm now thinking it's in the transmission with the shift drum, dogs, etc but I want to throw it out to the real experts. Besides not being knowledgeable about transmissions, I really don't want to have to split the cases unless absolutely necessary. Again, shifting is smooth until about 20 miles in and then it starts getting progressively worse.

[chef1366]

Sounds like either the clutch adjustment (you seemed to have covered that) or the wrong oil weight.

[mehall2]

I've tried the regular Castrol 10w40 motorcycle oil and I've recently put in some of the Rotella 15W which many folks seem to like in this forum. The shifting has gotten worse recently and I don't know if it's related to the Rotella or just a coincidence.

[chef1366]

With the clutch adjustment on the lever all the way together loosen the adjuster on the sprocket cover until you have a quarter lever of play. Now adjust the lever until you have 1-2mm of play.

[mehall2]

I think what I'm experiencing is backlash from what I've read. I don't know about the issues with downshifting but I'm at the point where I think I'll ride it like it is and tear into it next winter. It takes about an hour of constant running to start acting up.