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Welded front sprocket
Posted: 09:24 am Jul 15 2019
by Parney
Some clown has brazed the front sprocket to shaft on my kids 220 only noticed it yesterday any body advice on removing it at home
Re: Welded front sprocket
Posted: 10:24 am Jul 15 2019
by KDXGarage
Air die grinder,
may need a new shaft and sprocket, splitting the cases of course
Sorry to hear it
Re: Welded front sprocket
Posted: 11:03 am Jul 15 2019
by kdxsully
Dremel cutoff wheel... maybe.
Re: Welded front sprocket
Posted: 12:38 pm Jul 15 2019
by KDXGarage
Yeah, go with that first.
Hold off on the big stuff.
Re: Welded front sprocket
Posted: 01:43 pm Jul 15 2019
by Molly's 70
Is it brazed or welded?
If brazed, it could be melted off with a torch. Brazing rod melts around 900 to 1000 degrees. Use a wire brush to help remove the brass or bronze, then pull it off & cool it down before it melts the seal.
If welded, I would sand or grind down the weldment as much as possible. Steel melts around 2700-2800 degrees. The fiber cutoff wheels work great as already suggested. A hammer can help compromise what's left sometimes. Depends on penetration. It can be done. Just take your time.
I can tell you what your up against with a picture.
Re: Welded front sprocket
Posted: 04:44 pm Jul 15 2019
by kdxsully
Molly's 70 wrote: ↑01:43 pm Jul 15 2019
Is it brazed or welded?
If brazed, it could be melted off with a torch. Brazing rod melts around 900 to 1000 degrees. Use a wire brush to help remove the brass or bronze, then pull it off & cool it down before it melts the seal.
If welded, I would sand or grind down the weldment as much as possible. Steel melts around 2700-2800 degrees. The fiber cutoff wheels work great as already suggested. A hammer can help compromise what's left sometimes. Depends on penetration. It can be done. Just take your time.
I can tell you what your up against with a picture.
True, if brazed then an oxygen torch might be the ticket. I’d also recommend using that cooling gel stuff near the seal so it doesn’t melt and you have to replace that seal.
Re: Welded front sprocket
Posted: 08:33 pm Jul 15 2019
by rungrandpa
My son runs a welding business. He said he would pull the shaft out and use an acetylene torch to melt the braze job and that it would come right apart. His opinion is the seal is already ruined by the heat generated by the original braze job.
My nephew welded a shift pedal on a Honda 90 I restored. I took it off with power tools and it wasn't pretty.
Re: Welded front sprocket
Posted: 10:45 pm Jul 15 2019
by Parney
As always you kind people are right i took 3 hours to remove it and not a single slot left on shaft arrrrr that’s why it’s welded on ordered new shaft seals etc will up load pictures shortly what was left when I have calmed down
Re: Welded front sprocket
Posted: 11:56 pm Jul 15 2019
by kdxsully
Parney wrote: ↑10:45 pm Jul 15 2019
As always you kind people are right i took 3 hours to remove it and not a single slot left on shaft arrrrr that’s why it’s welded on ordered new shaft seals etc will up load pictures shortly what was left when I have calmed down
Were they filled in with weld? Did the slots get sheared somehow?
If they were filled in, I would guess it’s possible to carefully cut them back out. No way of knowing what’s really going on without pictures. Glad you got the sprocket off, the world of used bikes is unlike anything else.
Re: Welded front sprocket
Posted: 02:30 am Jul 16 2019
by KDXGarage
I don't think anyone is going to pull a shaft through that hole... or recut sprocket slots. New shaft, sprocket, collar, seal and o-rings is the way to go.
Re: Welded front sprocket
Posted: 03:12 am Jul 16 2019
by Molly's 70
KDXGarage wrote: ↑02:30 am Jul 16 2019
I don't think anyone is going to pull a shaft through that hole... or recut sprocket slots. New shaft, sprocket, collar, seal and o-rings is the way to go.
Agreed.
Re: Welded front sprocket
Posted: 11:54 am Jul 16 2019
by KDXGarage
Check the chain tension when it is all back together. Sorry that someone did that to the bike.
Re: Welded front sprocket
Posted: 07:21 pm Jul 16 2019
by Kdxfan4130
The heat treating might have changed after all the brazing and reheating if you chose to clean up the splines any ways. One of those amazing backyard fixes that possibly left the seal leaking a lot earlier in its life.
Re: Welded front sprocket
Posted: 02:45 pm Jul 17 2019
by Parney
Engine on bench just waiting for my case splitter tool due tomorrow. Not a bad job as long as you look at what people have experienced on this site did the swing arm bearings when engine on bench no need to take swing arm out as just enough room to pull a a threaded bar through and tube
Re: Welded front sprocket
Posted: 03:53 pm Jul 17 2019
by Molly's 70
Just out of curiosity, are you going to fix only the affected parts, or is this going to be a full on rebuild?
Re: Welded front sprocket
Posted: 02:20 pm Jul 18 2019
by Parney
Not a full re build but got all seals and bearings for the side case which I am lifting off and new shift bar.just waiting on case splitter got rubber hammer ready and eaten my frozen pizza so room in freezer for bearings
Re: Welded front sprocket
Posted: 02:35 pm Jul 19 2019
by Parney
Where have my spines gone that’s why it was welded when I turn this shaft the input shaft does not turn straight away seems to turn a little bit first is this normal
Re: Welded front sprocket
Posted: 03:00 pm Jul 19 2019
by Molly's 70
Ouch! That parts got to go.
Re: Welded front sprocket
Posted: 03:08 pm Jul 19 2019
by Kdxfan4130
Dang. Wonder what the splines look like on the cs sprocket. Heat treating gone awry?
Re: Welded front sprocket
Posted: 03:51 pm Jul 19 2019
by KDXGarage
chain tension may have gone awry
I assume one is not going to grab that with a hand and turn all the parts inside.