front end knocks

You should fix this right away as it could be dangerous. Take the front end out of the frame and inspect the bearings and races for wear, grease (or lack of), pitted races, etc. It might just need some grease and an adjustment (tighten).

Take the bars and top triple clamp off. Tighten the spanner nut (looks like a ring with square notches in it) under the triple clamp until it is snug. Your bike might have a regular hex nut instead of the spanner, no biggie. It will be the only nut underneath the top triple clamp. Grab the forks and turn the front wheel side to side. It should be smooth, not "bumpy". If you feel any bumps, your races (the hardened steel surfaces that the bearings roll on) are worn and need replaced. You can drive them out with a hammer and a punch (after you drop the forkes out of the head tube). It's pretty basic stuff that anyone can do, IMO.

Whether you just need to grease and adjust, or change parts, when putting back together, adjust so when fully assembled with bars on, there is no slop like you have now, but the bars turn smoothly, even falling to one side if on a center stand. FYI-I use channel lock pliers to loosen or tighten that spanner nut with no ill effects. :cool:

It could be as simple as the upper triple clamp being loose on the stem, but, like biglou said above, it should be taken off the bike so that you can check it all. If the upper clamp got loose, who knows what else did.

He is also right in that the front end is nothing to take lightly. The first time a steering stem bearing fails in a big way and the front end locks into some turn angle, or the upper clamp separates from the forks and the handlebars and all come off in your hands you will wish you had taken some time to check it over.

I have seen both happen, the second example up there is especially drastic as the throttle cable gets stretched so it is wide open, steering control is lost....well, it aint pretty.

^All of the above.

I bet your bearings collapsed. It wil lfeel smooth, but will rock. When you turn with the wheels off the ground can you rock it? Will it knock them?

If you don't fix it now, it will be issues very soon! I would fix it right away.

The nut on top of the triple clamp won't tighten up the steering head bearings. That nut is a spanner type and is directly below the top triple clamp. Sometimes you can get a punch or a screwdriver and tighten it without disassembly, but I'm not sure about your bike.

The way to check for loose steering head bearings is to but the bike on the stand with the front wheel off the ground (a friend weighting the back of the bike helps) and tug forward on the fork tubes. If you feel that clunk, the bearings are loose and/or hosed. If it's loose, tighten the steering head nut (the one under the top triple clamp) and check again. If it still thunks or it doesn't rotate smoothly, you'll have to disassemble and check it out.

I would guess the bearings are rusted and toast. "Greased from the factory" and Japanese bikes are mutually exclusive.

www.powersportspro.com has a Parts Fish parts finder with parts diagrams for your bike if you want to see what's what. Look at the Steering Stem and Handlebar Top Bridge diagrams.

1981- I am sure the bearings are gone- the races are probably worn too. Sounds very dangerous .

Get some new bearings top and bottom and read the manual on how to install and adjust and you should be good to go.

put the bike on a stand to get the wheels off the ground. then, grab the fork legs near the axle, and pull them in and out. I think you will find that the bearing in the stem is loose. loosen all the bolts for the upper triple clamp, then see if that center cap nut is loose. you may need to tap it lightly with a deal blow hammer to snug it back together. jumping can put ALOT of torsional strain on those stock triples, so they may just be loose. Don't forget to torque all those bolts back up too!
good luck!