Topic: SL100 Won't turn over, need help

[sl100]

Need help.  I rebuilt my 1972 Honda SL100 k2 and can not get it to start.  Will not even backfire.  It has a spark when you kick starter, it is getting gas (we can see/smell wet spark plug after kicking).  we've changed out gas in tank.  we've rebuilt, cleaned carburetor 2x.  We've checked valve clearance and points gap.  I've had 3 guys who have rebuilt Honda's look at it and they are stumped.  Everyone feels it should at least get an ignition or backfire.  I did see that sprocket on cam chain can be flipped, and we checked to make sure "O" mark is at TDC.  I've tried other forums but no one has any suggestions.  Any help or ideas you can provide is appreciated.

Stumped in Texas.

[HondanutRider]

The timing cam sits on the end of the valve cam with a little keyway or slot (or something...can't remember exactly set-up), that allows it to be mounted 180 degrees either way.  Try rotating that a half turn around so that the firing will be on the compression stroke, rather than the exhaust.

[754]

That is what I would look at first, or the advance cam was off the pin and turned 180 deg.