Broken Front Sprocket! -- New Pictures

Blue · January 06, 2010, 09:01:48 AM

Not much tech, but I thought I would share with everyone what I found yesterday when looking over the scoot (winter inspection/modification).
Anyone else experience this?

On another note; the stock gearing is 15/38 and I am currently running 15/40. I am thinking about going with 14/40 since I did not ride on the interstate once this last season and I rarely get the bike into 5th as it is. Any issues with the shorter gearing other than shifting more often?

erkishhorde · January 06, 2010, 09:18:12 AM

Check your chain for tight spots. Broken sprocket teeth generally means bad chain wear like tight spots or loose/broken links. I'd say you're due for a new chain along with that sprocket. If you really want to, you can continue to ride on that but if you don't have to you shouldn't. Don't listen to tunes while you ride, though, and when you're taking off from a stop listen for a pop. If you hear one, it means you broke another tooth.

Another thing, that muck looks kinda liquidy. Did you spray cleaner in there before taking the picture? If not, I'd check for an oil leak.

Some people have noted extra chain wear from doing the 14 front because it puts the chains closer tot he swing arm. Others haven't noticed it at all. *shrug*

Duck-Stew · January 06, 2010, 09:31:17 AM

Also, your rubber booty to keep dirt/grime out of the slave cylinder has expired. Either replace your slave cylinder w/a newer style aftermarket unit for better feel and lighter effort, or get a new rubber booty if you're OK w/the lever effort and clutch feel.

The chain looks new enough same w/the sprocket from the angle of the photo... so maybe a defective sprocket?!? It would be the first I've seen (other than did not fit on the output shaft) but could be...

+1 on the grime comment above. Clean it up and then see what you've got going on in there.

Blue · January 06, 2010, 09:34:28 AM

Quote from: erkishhorde on January 06, 2010, 09:18:12 AM
Check your chain for tight spots. Broken sprocket teeth generally means bad chain wear like tight spots or loose/broken links. I'd say you're due for a new chain along with that sprocket. If you really want to, you can continue to ride on that but if you don't have to you shouldn't. Don't listen to tunes while you ride, though, and when you're taking off from a stop listen for a pop. If you hear one, it means you broke another tooth.

I should have said that the chain is in excellent shape as is the rear sprocket and rest of the 14 teeth on the front. It just looks like the front tooth just let go. I have never seen this before (I have been riding for 14 years and have only ever owned chain drive bikes). This is my first Ducati so that is why I posted this question.

QuoteAnother thing, that muck looks kinda liquidy. Did you spray cleaner in there before taking the picture? If not, I'd check for an oil leak.

I did just lube the chain as part of my winter maintenance. That is how I discovered this. Also, I did spray cleaner in there to get rid of the built up chain junk.

QuoteSome people have noted extra chain wear from doing the 14 front because it puts the chains closer tot he swing arm. Others haven't noticed it at all. *shrug*

I always prefer adding teeth to the rear, but the chain and rear sprocket is still in good shape.

Blue · January 06, 2010, 09:36:34 AM

Quote from: Duck-Stew on January 06, 2010, 09:31:17 AM
Also, your rubber booty to keep dirt/grime out of the slave cylinder has expired. Either replace your slave cylinder w/a newer style aftermarket unit for better feel and lighter effort, or get a new rubber booty if you're OK w/the lever effort and clutch feel.

Yes, I noticed that too. It is on the list along with a new front sprocket. Actually, I haven't noticed an issue with the stock slave yet, but I do not have to deal with stop and go traffic in my daily life.

QuoteThe chain looks new enough same w/the sprocket from the angle of the photo... so maybe a defective sprocket?!? It would be the first I've seen (other than did not fit on the output shaft) but could be...

This is my thought and the first I have ever had.

NAKID · January 06, 2010, 10:22:52 AM

Is it possible you get a rock kicked up into it and that's what broke the tooth?

erkishhorde · January 06, 2010, 10:37:25 AM

Ah, I was wondering what that thing was in the top muck that contacted the chain. Since you're digging around in there anyway, now is as a good of a time as any to put in a case saver. It helps keep some of the muck away from the slave too.

Blue · January 06, 2010, 10:40:24 AM

Quote from: NAKID on January 06, 2010, 10:22:52 AM
Is it possible you get a rock kicked up into it and that's what broke the tooth?

I guess it is possible, but I had the sprocket cover on all season.

I would think it would be hard for rock to get in there?

Blue · January 06, 2010, 10:42:49 AM

Quote from: erkishhorde on January 06, 2010, 10:37:25 AM
Ah, I was wondering what that thing was in the top muck that contacted the chain. Since you're digging around in there anyway, now is as a good of a time as any to put in a case saver. It helps keep some of the muck away from the slave too.

Yeah, I saw those on the CA-Cycle Works website. I am going to pick one up. On another bike I had, the chain snapped and the case saver saved the clutch pushrod and cases.

erkishhorde · January 06, 2010, 10:43:39 AM

Maybe front and rear sprocket aren't aligned?

battlecry · January 06, 2010, 10:44:47 AM

Gee, Blue, so you have a 14 tooth sprocket that won't wear on the swingarm!

Speeddog · January 06, 2010, 10:57:14 AM

I'd say that broken tooth was from a rock or other debris.

Check the inside of your chain for damage, if something got pinched in there hard enough to break that tooth, it might have damaged the chain as well.

stopintime · January 06, 2010, 01:52:08 PM

Is it just me, or does it look like the "teeth" inside the sprocket do not connect to the grooves correctly (I'm not sure that's what they are called, but...) Are they eating their way into where they shouldn't be?

battlecry · January 06, 2010, 02:13:33 PM

No, it's fine, stopintime. The splined plate is there to lock the sprocket from coming out. So the teeth should hit the splines in the sprocket. What you do not see is the groove where the spline plate sits. You insert the plate until it seats in the groove, then rotate it until the teeth are caught by the splines, securing the sprocket (in the in-out direction), then you make the assembly solid with the two bolts.

stopintime · January 06, 2010, 02:19:28 PM

Quote from: battlecry on January 06, 2010, 02:13:33 PM
No, it's fine, stopintime. The splined plate is there to lock the sprocket from coming out. So the teeth should hit the splines in the sprocket. What you do not see is the groove where the spline plate sits. You insert the plate until it seats in the groove, then rotate it until the teeth are caught by the splines, securing the sprocket (in the in-out direction), then you make the assembly solid with the two bolts.

It has been a good day for me and now it's completed with new knowledge

News:

Broken Front Sprocket! -- New Pictures