jeffz
Full Member
Posts: 215
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Post by jeffz on Aug 4, 2008 19:31:15 GMT -5
I bought a new tire and decided to check the swing arm bearings and replace the chain as long as I had everything apart. I took the cover off only to find the sprocket had been welded to the counter shaft! Previous owner must have stripped the threads on the end and decided that welding it was the easiest fix. I've come up with a couple different ideas on how to fix it. I'd like to just reweld it to get me by until this winter when I have the engine out to replace the base gasket. I'm either going to try and fix the old one, or buy a new/used one. One way I was thinking of fixing it, is to drill and tap the end of it and use a large spacer and a bolt to hold the sprocket on. Another thought is to turn the old threads off and chase new smaller threads on and make a new nut to fit. One thing I'd like to know before I try this is if the shaft is case-hardened. Makes things a little harder (pun?) but not impossible. I'll probably end up replacing it, but I'm trying to weigh my options. I was going to upload a pic, but can't get my host to cooperate, so if someone wants to host it, I can email it to them. Thanks!
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Post by G Man on Aug 4, 2008 19:46:11 GMT -5
... I was going to upload a pic, but can't get my host to cooperate, so if someone wants to host it, I can email it to them. Thanks! No need to mess with fussy pic hosting sites Jeff. I know you usually use putfile. Just use www.tinypic.comQuick upload of your pic to tinypic, copy the url and paste it here with your img tags. Now let's see what you've got going on there... G Man |
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Post by solo2racr on Aug 4, 2008 21:13:52 GMT -5
Yes, The shaft is hardened. There isn't much of any side load here so, almost any method to keep it on the shaft will work. Drilling and tapping the end of the shaft is one fix. It's normally easier to do internal threads than external ones. One other way would be to cross drill the shaft and use a cotter pin to retain the sprocket. Take up the excess space with a spacer.
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pcnsd
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Posts: 113
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Post by pcnsd on Aug 4, 2008 21:42:16 GMT -5
In the short term -
You can grind the old weld and use a puller to remove the sprocket. You can pound a new sprocket back on the shaft and weld it in place. The shaft is (was) hardened. Now, in the weld effected zone there is no telling what has happened to the metal, but probability suggest for me that it is annealed or close to it. Along the borders of the heat zone the metals are now different and will likely crack if given enough time and load.
In the long term -
The output shaft is junk. You can still purchase new from Yamaha for a small fortune or find complete transmissions on E-bay at a reasonable price if you are patient.
Good luck
PC
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jeffz
Full Member
Posts: 215
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Post by jeffz on Aug 5, 2008 12:24:34 GMT -5
Forgot to say that the weld is already broken, and the sprocket can move back and forth very slightly. It still catches on the spline and everything. I don't know how long it's been broken, but when I get the swingarm and wheel back on, i'm just going to weld it back on. If it breaks again because of the difference in steel, i'll grind the welds off and tap the end of the shaft. Link to picture because it's huge. ;D tinypic.com/view.php?pic=2euilp1&s=4 |
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Post by StewRoss on Aug 6, 2008 3:41:57 GMT -5
There is a seal behind the sprocket and an O ring on the shaft as well...not conducive to heat being applied during welding! SR  |
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Post by caferacercarl on Aug 6, 2008 4:10:39 GMT -5
llisten to the wise Stew, can't count the welded on sprockets I've seen, even bought one myself, a Z750 twin from the wreckers, thought i was smart getting it running and re spraying it, etc, untill i took the cover off......... oh welll.....
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jeffz
Full Member
Posts: 215
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Post by jeffz on Aug 6, 2008 12:23:42 GMT -5
I've found XT countershaft assembly's on ebay for less than $75, so I will probably go that route. Otherwise, the shaft itself from Yamaha is $150!
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