I dont know if you've ever ridden a DRZ400 but they are not fast bikes at all. I would still be able to ride with my GF no problem but have the option of wheelies without having to install my modified oil pump. I mean I have all the parts to make my grom do it. The part Im starting to get frustrated with is chasing my tail. I have everything needed and now have overheating issues. I'm struggling with having to part with another $700 for a side cover and oil cooler. I mean I've come this far so whats another $700? I dont know. Its still a struggle I guess. I'll definitely give you and Ninelives first crack at anything I sell if I do decide to part ways with this bike.Phoenix, I hate to hear that you might stop Groming. I figured you needed that bike to ride with the girlfriend.
If you do decide to part your bike out, let me know. I could probably use an aRacer or Hindle or whatever. As long as they are not scratched up...lol. My OCD and all...
I agree with you on the fact that it looks like a factory defect failure. I think Im with you on switching to the Takegawa. The Koso may have been a fluke but if it happened again you'd be kicking yourself.The alignment of the sprocket to chain was great, the shim actually throws it off which is why you only use it if necessary. I am positive that I did not need the shim, there was no binding or drag whatsoever. If it had binded, the sprocket would have been up and safely tucked out of the way instead of sheared off and fully bottomed out.
Yes, the transmission gears did clearance the tensioner arm when it fully extended the tensioner. Not much, but it definitely removed some aluminum.
I do not feel like replacing the chain was needed, at my power level that chain will probably live forever. You would notice excessive stretch a long time before failure. It appears to me that the bolt that secured the wheel to the tensioner sheared, due to defect or being over torqued. That allowed the chain to get loose and the piston smacked the exhaust valve bending it. That locked the cam sprocket which then broke the chain.
It is definitely a crappy situation, the Koso unit "looked" nice. I was not concerned with the metal idler, both cam and crank sprockets are metal....... so no issues there. I do not know if it is a bad design or I just won the manufacturing defect lottery. I can not afford to take the risk again by buying another Koso. I will step up to Takegawa most likely, since the upgraded valve springs will surely tax the oem tensioner even more. I could fix the engine cheaply with a new exhaust valve, new chain, and new tensioner. Probably 150 bucks, but why? Ported head and hi-comp piston, with 34mm throttle body and manifold sound like fun!