suzuki gs1000 st

[met]

hi all,

amongst the many other things that will follow, im just in the process of replacing the chain and sprocket on my st....

please see video showing what i found after removing the side case.

https://youtu.be/ZjTZuRUBAe4

i have this small sprocket which is held on by 3 phillips screws.
over this is a nut which is freeplaying but doesn't seem to go anywhere, either in or out.
if you look closely it looks like it may have been once welded, as there are two weld marks on it.
as ive never seen this before, my question is:...
is this normal ? .................and if not, what is supposed to be the correct procedure in untightening this nut,
in order to pull out and replace the sprocket...?
and later, the correct procedure in tightening this after finishing with the job?

a little stumped here....

thanks in advance
m

[chuck hahn]

Thats the wrong nut and i would bet your threads are torn to pieces. Your basically screwed unless you weld the nut back on or do some tranny work is my thought.

[fastbysuzuki]

Yes ime with chuck's response. Good luck either way.

[Guest]

That's sad to see! To repair that correctly, it's going to be a big job.

[Guest]

Pull it all off and post a picture. Hopefully it's not as bad as we think.

[uk gs nut]

New output shaft and engine out I think, that is a stock damper held on with 3 screws. Not needed.

[met]

thanks everyone for your input.

after grinding away the weld, i have removed the nut and the sprocket
and added another video of this.

https://www.youtube.com/watch?v=kmq9bnGxqmM

as chuck says, the thread is rooted.

this leaves me with two options:

1. replace chain and sprocket and close of with nut and weld.
2. replace chain and sprocket and close of with nut and split pin after i drill
at the end of spindle.

i didnt want to pull down half the bike to fix this because there is no need at present. i figure i can come back and do it properly, when the tranny goes.

in the meantime, i'm looking for better ideas......?

m

[chuck hahn]

You may be waiting the rest of your life for then tranny to fail. Sereuosly though, you can pull the engine in less than an hour, an hour to pop the bottom end off, and swap out the countershaft. Its not as daunting a task as you may be expecting.

[mnferwerda]

Maybe a bad/dumb idea, but could you re-tap the shaft with a smaller diameter thread and use an appropriate nut? I don't think there is a huge amount of stress going on there. It just needs to keep the sprocket on the shaft. Actually tapping it while on the bike might be problematic though.

[Guest]

Maybe a bad/dumb idea, but could you re-tap the shaft with a smaller diameter thread and use an appropriate nut? I don't think there is a huge amount of stress going on there. It just needs to keep the sprocket on the shaft. Actually tapping it while on the bike might be problematic though.

Running a die over it to refresh threads to the next size smaller is possible and it's the way I would do it if it were mine.
Depending on how inclined you are to do that, you may want a machinist to help out.
I see no side pressure on this but I welcome someone more knowledgeable to correct me.

[met]

thanks folks for the input.....tapping is worth a try.
might be the go....!!!!

cheers

[chuck hahn]

DIE not a TAP.

[met]

sorry, yes a die....

it should be a 20mm thread which is now gone.....
im thinking perhaps a 19mm die with 1 pitch might do it....
perhaps even an 18mm with 1 pitch ....?

and perhaps a right hand thread,
as that sprocket is always spinning to the left....?

[Guest]

With a micrometer or calipers measure where you are at right now. Measure the lowest spot.
Now comes the tricky part. Put the bike on the center stand and start it in a well ventilated area.
Put it in 5th gear and spin the shaft.
Now with a file, carefully file the shaft smooth and straight to the size you are going to thread it (preferably 19 mm).
Put a 2-3 mm chamfer on the end of the shaft.
Find a die like this one http://www.ebay.com/itm/Drill-Americ...IAAOSwPCVX3d4V and a socket to drive it.
Right hand thread is ok.
With the engine off and the transmission in first gear, start the die as perfectly perpendicular to the shaft as possible.
Watch for the welded areas as they may have become hardened due to the heat.
Use plenty of cutting fluid and run the die to the shoulder.

And by the way, don't buy a cheap die, you will only make the job tougher.

[chuck hahn]

Its a right hand thread from then factory. Be sure to get a way to use then stock locking ring deal that you bend over one of the flats on the nut. Idea is to secure the nut so it doesnt loosen when your riding and throw the chain...which is probably what originally happened to lead to the previous owners weld job.