Hello all, new member and first post. I have gone through ever post I could find when rebuilding the quad and have tried everything I can think of. I am having an issue after the rebuild and was hoping someone could help. I have set the timing four times at this point and still have a no start and recently had two backfires that knocked the carburetor off the intake manifold. My issue is every time I align the lines on the cam sprocket to the block I have a good amount of play in the cam (like an sixteenth of a turn) it was the same on the old cam and new cam (niche performance cam). The reason I did the rebuild was to get rid of the cam chain knock noise with a Part # 14401-MEB-671 cam chain for a CRF 450r. I read in multiple posts that it was the best cam chain to use for this application. Could this be the issue? I also replaced the tensioner with a manual tensioner. The decompression pin was not used when I took the engine apart and I didn’t put one in as I used an aftermarket cam. I set the valve lash and replaced the coil and cdi. The fuel might be degraded but I tried staring it with staring fluid and it didn’t start. Any advice would be appreciated, thanks.