Fix what? The front sprocket. It wears the spline on the counter shaft & starts to "wobble along the shaft." A surprise; but it should not be. This is the 3rd time round @ 320,000 kms. The first two times 100,000 kms apart & # 3 is 92,000 kms. Eventually you need to replace the counter shaft & that is the very last piece to come out of the motor when you strip it down = ouch! And "laugh" the gasket kit costs more than the shaft. As I'm off to Laos I need a quick fix for 1,500- 2,000 ms. let's try welding the locking plate on. Price 350 baht at Somchit's Daeng Glon Pratu Will it work? Yes, if done properly, I hope. The next week or two will tell. What causes it 1. chain too tight 2. lugging the motor in low a gear too much 3. any more ideas? or is it just 100,000 kms per countershaft?