bottom end click/clunk

[kamesama980]

Just noticed the noise today sitting at a stop light. harder than a click but not hard enough to feel in the seat, frame, or engine. It's most noticeable at idle (~1200rpm), goes away ~1500rpm. Pretty sure it's not in the crank/rods/pistons or head because it's about 1/second at idle.

My bike's a '77 GS400x. odometer says 13,500mi but the speedo gear in the hub is broken. I got it last summer, got it working this summer, and have been riding the last month or so, 200 miles wild guess. Cleaned carbs, did valves, and head gasket. It's due for an oil change. I use the clutch to shift except I tried running through the gears without it about twice (yesterday). Also, the 2-1 downshift gets stuck in neutral. I give it a nudge, barely more than a touch, to go back to 2nd then kick down to 1st just fine.

Should I just change the oil and see how it goes?

[ryonker]

Change your oil (use something good like amsoil 20w 50 or Rotella 15w 40).

Keep an eye on things. I don't think I would continue shifting without the clutch.

Some of the shifting issues could be just you getting used to the bike. A couple times I had the same deal where I would get into neutral and have to fiddle a bit to get it back into gear. It was mostly me just getting used to shifting my bike. I know have a rythem of shifting that works well with few miss shifts.

As far as the sound, it's hard to tell. If you do a search, there are a few issues that result in weird engine sounds. I am not sure of any that relate specifically to your bike. Just be aware and listen. I now have a cheap auto-stethoscope to pinpoint sounds if they come along.

Good luck!

Rick

[kamesama980]

That's about what I figured. I haven't been shifting w/o the clutch since and the 2-1 shift was fine till this started. it actually feels more like it gets stuck between N and 1st like the shift drum goes cockeyed or something. Oils getting changed tmw afternoon, anything but fram I have to order

[rustybronco]

anything but fram I have to order

That's what I have on the shelf and in my bikes. have you had a problem with them?

[chuck hahn]

I had a " MYSTERY " clunk a month ago too.. I have a 77 and a 78 GS 750. after going thru everyting i could think of i discovered that BOTH of the side engine mounts had vibrated loose and were letting the motor vibrate.. Check yours and if they are loose take them out all they way and put some thread locker on them and reinstall... should be a tear drop shaped lock that fits into a pocket on the sides of the motor that the bolt fastens too..

[kamesama980]

The best thing I've ever heard about Fram filters is that it's OK (and only OK performance) if you change them on time every time and don't do anything other than moderate driving. Every study on filters I've read says about the same. Fram is a decent baseline, nothing more. there are worse but there are many better.

As for the noise, I think I found it... was at leaving the parts store (picking up the WIX filter for those who care). started it, kicked it into 1st, and the bike died like I hit the kill switch (not like it ran into a mechanical wall like something jammed it up). so I try to go back to neutral to start it again (kick start only) and the shifter doesn't do anything. still stiff and normal range of motion but no satisfying kachunk and slight resistance of the transmission doing it's thing. so, walk home, got the truck, load the bike up and now it's sitting in the driveway waiting for me to figure out what to do with it.

*update*
Drained the oil and found a little machined pin. Just a guess but I don't think it goes there. Everything's unbolted, now I just have to find the right angle to lift the engine out of the frame. Guess I can do it a piece at a time

*update again* didn't have to pull the engine out of the frame... hooray. after pulling off the clutch side engine cover found a little disk loose. did some looking in the book, looks like the pin goes in the end of the shift drum and is what the shifter moves. the disk holds it in. Also found the screw that holds the disk onto the shift drum... looks like it broke too