Bad clunk on clutch take up

[chewy4x4]

Ok I am starting to think I am not relaying my issue properly. Can yall describe the sounds and issues I would have if I had drive shaft problems or final drive problems. I only get my issue after the clutch has engaged and I am already moving forward. I have power transferring through the bike. So i get the sound after I shift. Its like I have the center stand jumping and slamming into the swing arm. It only seems to happen once the bike is warm. I also had only light metal dust on the transmission drain magnet. So its like this Clutch in-shift-clutch out- start moving-clunk  and I can only tell in first and second gear after its hot. In first its a hard clunk.

[Bob_Roller]

There are what are called 'cush drives', one in the transmission, and one on the drive shaft .

It's kind of like a spring loaded ball and socket type assembly, we've heard from a members here, that the spring I guess gets weak, and instead of every thing being pushed together by the spring, the ball and socket disengage on starting from a stop, or on deceleration, and makes a thumping, or banging noise as the parts engage and disengage .

[chewy4x4]

So where should I look? Can the bike live like this for a while or is this a do it now kind of issue?

[Bob_Roller]

First thing I would do, is to drain the oil out of the transmission and drive shaft, and see if there is an abnormal amount of metal there, might be able to narrow it down to which is bad .

This is an issue that needs to be taken care of in a timely manner, you're only going to damage parts, and they are a bit on the pricey side .

[chewy4x4]

Well the tranny fluid looked fine just light metal dust and little of that. I havent drained the final drive yet. What gear oil do I use for that?

[Ed Miller]

"What gear oil do I use for that? "  The owner's manual has that listed (gentle hint) but you can use normal hypoid gear lube, something like 75 or 80-90.  Same in the driveshaft tube and gearbox, though I've been told to use straight 50 wt motor oil in the gear box.  I don't do it because I go by the owner's manual, but I've been told.  :-)


If you think the clunking might be in the drive train, try playing around with it by putting the bike on the center stand, in gear, and rotating the rear tire and seeing if you can repeat the sound.  There will be some free play for the tire to turn, so just move it one way and the other against the resistance from the motor.

[chewy4x4]

Ed concerning the owners manual; not all of us are blessed with one of those. Also thank you I will pick up some oil. How do I drain and fill the drive shaft tube?

[Bob_Roller]

There's a drain plug at the forward end of the final drive, at the bottom .

To fill the drive shaft, there's a fill port on the top of the final drive housing in the same area .

You need 150 ml of gear lube of your choice to properly service the drive shaft .

[chewy4x4]

So there is no separate fill for the drive shaft. Good Because I thought I was just missing something.

[Rob Valdez 79 R65]

So there is no separate fill for the drive shaft. Good Because I thought I was just missing something.

There are 3 places gear lube are used:

• the transmission
• the drive shaft (fill/drain on the final drive boss that bolts to the swingarm)
• the final drive - fill/drain holes can vary according to year

Riders handbooks are available from dealers and are invaluable.

[montmil]

Oil types and weights and quantities are spec'ed in both the Clymer and Haynes manuals as well.

Monte

[chewy4x4]

Ok final drive oil fine. Driveshaft oil........Missing [smiley=shocked.gif]. This has been corrected and the clunk is gone but I am afraid the damage might be done I picked up a spare driveshaft lastnight.

[Bob_Roller]

I've seen postings on the drive shaft oil migrating to the final drive, via the final drive input seal .

Not quite sure how it does this, all I know, is that it does happen .

You may want to periodically check the drive shaft oil level,and see if it goes down over a period of time, if it does, the final drive input seal will probably require replacement .

If you're wondering how to check the drive shaft oil level, my advice would be to make sure the final drive oil is serviced to the over flow port, at the back side of the final drive housing, then, in 500 or so miles, remove the over flow plug, on a 'cold' bike, and see if you get oil draining out of the port, if it does, good chance you have oil migrating past the input seal . .

[Rob Valdez 79 R65]

Did anyone mention being VERY CAREFUL not to tighten those fill/drain screws on the driveshaft?

They are very easily stripped, and then you have another problem.

If the drain is leaking oil, you need to perhaps try a different crush washer.  
I like the copper ones that Hucky's sells, myself.

[chewy4x4]

I will keep up on it. No leaks so far and I tightened to just past snug. But thanks Rob I keep it in mind.