In reverse the rev limiter is set much lower than forward . So thats most likely the cause of the sputtering. If you want to eliminate the rev limiter in reverse, search the past postings for explainations and how tos.
Compression is supposed to be 163 PSI minimum, for stock motor. Hows the compression on that motor? And yes there is a decompression device for the motor , but the only way to check it is when the cam is out. But if its sticking, the compression will be way low .
The timing chain adjusts automaticly...until its adjuster is worn out. and at that point, its very noisey.

 

I know somebody that had this problem and it ended up 2 hours of use after he heard the knocking in the head that a whitish smoke was coming out of the exhuast and it ended up leading to a scored piston and cylinder. He got it fixed be changing the piston and and cylinder. now there is no knocking on the head.

 

off topic kind of but did he get water in his air box and got sucked into the carb ?

 

Thanks HondaBuster! That was the info I needed!! I guess I have to take the cam out. How do I free the decompression valve up? I do the test with the throttle open or closed? Since I don't have my manual, what the best way to check for a worn timing chain and should I change the timing gears even if there is no wear? i.e. "shark fin looking teeth" hope u understand that term.

A little off topic here: How many of you Guys and Gals use a Stethascope (hope I spelled it right), to check for engine noise? I use it all the time from bad bearings to worn out injectors and cam shafts