Down for the year - sprocket/driveshaft

[ndbaker]

Headed out for a quick ride this evening and before I even left my neighborhood I lost all power to the wheel and had a loud clanking noise down by the transmission. I pushed the bike back home (1/2 mile), clanking all the way. As I pushed it up my driveway I heard the clutch cable snap (clanking noise ended too). Turns out the nut that holds the sprocket came off at some point (nowhere to be found), the sprocket had dropped onto the thread of the counter shaft and was rubbing against the clutch cable, caused it to snap and knocked out a chain link pin. New chain, new clutch cable are not really an issue. What pains me the most is that the sprocket stripped all thread off end of the counter shaft.

Is it possible to rethread the end of the counter shaft and put on a new nut? Or do I have to replace the counter shaft? Haven't looked into how to remove this, but I'm fearing that Ill have to tear about the entire transmission. Thoughts?

Please keep this GS in your thoughts and prayers.

 

[mike_of_bbg]

You should replace the drive shaft. Splitting the cases to get to the shaft is really not that difficult a task once the motor is out. Of course I was in there for crank replacement and left the transmission alone altogether. Lots of parts out there on eBay for not too much scratch, I think she can ride again.

 

[ndbaker]

Here's a picture of my situation. The threads on the counter shaft are completely stripped. At this time I am not cracking the case to replace so I'm looking to either try to rethread, use a shaft collar, or weld sprocket in place. The sprocket is in good shape and I don't see myself replacing for years. I only ride 1-2 k miles a year. Anyone come across this problem? Thoughts?

 

[Guest]

wow, that's crazy. Sorry to hear of your troubles. Never had this problem, I'll be interested to hear of a solution other than your own, that will work for sure. I guess you could always buy a new sprocket for $14 too and then you know you're ok for a long time to come.

 

[koolaid_kid]

Since you refuse to split the cases (the correct solution) I would have the sprocket welded on.

 

[Guest]

I think if it were me I would find a washer to put up against the sprocket and space it over enough so I could drill through the shaft to about 6mm then I would just put a bolt through it with a nylock nut on it. or even a cotter pin [large] All that holds the sprocket on my EX race bike is a snap ring. as long as the sprocket stays on the splines of the shaft there is no strain on the end of the shaft

 

[chedd]

rethread the shaft ,get hold of a nut to match the new thread.space out the sprocket with aflat washer so the chain don't eat the casing.fix the nut with threadlock a new tab washer.worked for me and lasted several years.

 

[ndbaker]

What do you mean space out with a washer? I still have the locktab washer to bend over a new nut if I rethread.

 

[markb]

replacing whole shaft is the right way to do it.

i would find the nut for it. then use washers to space the nut to the end of the shaft. get it as tight as you can, then put a light weld on it. don't go crazy on the weld. if you space it right, you can just grind the weld off and take it all apart.

other option is to find a die that you can rethread the shaft without removing it. you might have to fabricate a tool to move/hold the die that large.

 

[ndbaker]

I measured the shaft and its 18.4mm thick, remember no threads left so its nearly perfectly smooth. I'm going to buy a nut shaped die, but not sure what size to get. Considering 18mm or a 23/32". I'm pretty sure these die's are sized by the major diameter, correct?

 

[ndbaker]

18mm hex die and 2 washers on their way. Hope to be ready by Sunday, although 50 degrees and cloudy is far from ideal riding...wish we had year round riding like you socal folks! Will keep you all posted.

 

[chedd]

What do you mean space out with a washer? I still have the locktab washer to bend over a new nut if I rethread.

the washer is to make sure you get the chain in line with the back wheel,once you cut the new thread.this is what I did when the same thing happened to me anyway,i guess its trial and error.

 

[Guest]

Was looking at the pic of your sprocket and chain, that chain looks like toast, lots of rust on it? Sprocket looks a bit worn as well. If so, would be a good time to up grade the sprockets and chain. Is your stock gear a 630 or 530 set up? If it is the 630, then I would do a 530 conversion.

 

[boontonmike]

I did the same thing in spring. Major bummer. Looking forward to seeing how that works out with the die set.

 

[blackhammer]

did you end up getting the die onto this and re threading? Ive got the same problem with a replacement 1150 i just picked up.

 

[Guest]

How or why are your sprocket nuts coming off in the first place?

 

[blackhammer]

Previous owner of this motor in my case.

 

[ndbaker]

Just ran the 18mm die and the thread came out perfect. I was worried the shaft was too hard of metal for the die but I was wrong. Still waiting on the jam nut frm fastenal and ill be all set! Hoping for at least 1 more ride this year...weather permitting.

 

[ndbaker]

I did the same thing in spring. Major bummer. Looking forward to seeing how that works out with the die set.

How did you fix it?

 

[boontonmike]

How did you fix it?

I haven't. Been sapped for time and space. Where did you get the new tap and nut?