can anyone shed any light on why the sprocket has lost some teeth? over tensioned? it looked new when i bought the bike in sept last year.
If that's the original sprocket then I'm not surprised that it's knackered. I seldom see chains and sprockets lasting much more than 17,000 miles. The front sprockets wear twice as fast.
Once the chain has worn beyond a certain point the sprockets go quite quickly. You should renew the chain and both sprockets.
You're doing well at 17K. I rarely get past 15. My KTM 1190 is typically 12K. I put that down to that particular bike having a long chain run and long travel suspension. More sag from the weight of the chain and more lash as the suspension works. Good point about the front sprocket. I suspect many people rarely if ever inspect the front. They go by rear wear. I check mine because I'm OCD about keeping gunge at bay around the front sprocket area so I frequently have the front cover off for a deep clean. I wonder how may regularly check for tight spots too. They accelerate wear rapidly. Chain maintenance is a pita but has to be done. I had a chain snap on me once (not lack of maintenance but poor fitting by the workshop that fitted it). It is not an experience I recommend.
The aluminium ones go in a flash once they reach a certain point. I think the hard coating only penetrates the surface a small amount.
Maybe the sprocket was replaced without the chain? Many years ago, I had a Ducati 250 Scrambler, the front sprocket wore so badly that it was skipping chain teeth under load. The chain and rear sprocket looked OK to me and, as I didn't know any better I just replaced the front sprocket. It was just a matter of weeks until it wore down the same as before due to the worn/stretched chain eating it away. That was when I found out you should change the whole chain/sprocket combo at the same time.
Its a Ducati, more likely cheese! OE chain and sprockets were only of Dairylea standard on my 2013 Multi, not even mature cheddar grade…
Twins will take out sprockets and chains more so than fours. I know a rider with a cbr 500r, the sprockets and chain needed replacing by 10 k. Standard Honda items. I have used Renthal on a few bikes to alter the gearing, with a new chain, can't say I've had a problem with them. However lubrication and correct chain adjustment is a must. If you want to change one part you should do all.
I've been using Renthal alloy rear sprockets on my 916, they last for a good few years/miles and hold up well. On that basis, I tried the same on my Monster but it munched through it in little over a year, now it is only a 520 vs. a 525 setup so not quite as strong as on the 916 but the increased wear rate was incredible. The Monster also gets through rear tyres, chains, clutches and even gearboxes (stripped 4 teeth off 6th gear) far, far quicker than the 916 does despite being 30hp down on the 916. Can only assume it's down to the less 'sophisticated' way in which it delivers that power?
