Hey we imported a pit bike that was 110cc, it was a good lil bike, steel frame USDs, then we sold it and got there next model, which is the 2005 Thumpstar Pro Replica, I did thrash it, jumping big etc but I dont think this should have happened. Read below and let me know if you have heard this happen or if you know how we can solve.
First it started with the chain adjusters on bike bent within 10-30min riding on the Left/Chain side of bike, so we had high quality chain adjusters built.
Next problem was chain kept coming loose/stretching and snapping, so we got a Top Quality RK chains
Next problem, we noticed bent swing arm to the Left/Chain side and rear wheel tight, so pulled to bits and found that swing arm axle and rear wheel axle were bent both on Left/Chain side. So we got better quality axles(12grade steel)
Next problem, engine cracks on bike and drops all oil, main shaft( front sprocket) has been pulled back. 12grade steel axles have also bent again.
Option 1. The most likely reason is because swing sits on a almost 45 degree angle of swing arm the engine is putting to much load on chain and engine which has caused faulty parts and engine crack.
Option 2. There is a opposite effect when suspension is compressing and decompressing. On Honda's, Yamaha etc, when suspension compresses chain goes from loose to tight. On these New Era bikes because swing arm sits on almost 45 degree angle it gives opposite effect, chain goes from tight to loose. When suspension compresses chain will go loose and bike will take up the slack in chain, so when suspension decompresses chain goes tight which may be putting excessive force on bike.
Option 3. We had none of these problems on our 110cc, so maybe 125cc engine is to powerful and putting to much stress on bike and parts.
Option 4. Bad quality material.
Lower rear end on bike, this will take 45 degree angle away and hopefully all the load. Test a 110cc engine.
What do you guys think? everything on bike seems to be well made, seems to be some sort of design fault????