Okay . . . i'm stumped.

Few months back, my cam chain broke.  It broke at idle, and a i didn't hear any smashing sounds, so i crossed my fingers and hoped i didn't have a bent valve or punched piston.

I pulled the motor and dissasembled it.  I was in luck!  Piston looked good (no holes or marks), valves appear to seat properly.  So, i order the replacement parts and put the motor back together.  

Compression is good.  i can turn the motor over by hand (with a 17mm socket, that is), good amount of resistance, but I can turn it over.  

but, i go to start it, and not much happens.  Seems like the starter is trying to turn the motor over, but it seems like there is too much resistance.  So, it doesn't turn over at all.  just makes some clicking sounds.  

So, i'm thinking something is up with the decompression selenoid thingy.  I look at it when i hit the starter button.  It definitely moves a little, but I'm not convinced it's working right.  I tried adjusting it to both extremes, stopping at a few intervals along the way.  But, always the same result . . . seems like the starter can't turn the motor over.

Anyone have any ideas?  

I'm leaning toward the culprit being with the exhaust valves.  Either the decompression thingy is not opening the exhaust valves properly (maybe it's broken, or just not adjusted right?), or with the exhaust valves themselves (maybe they really are bent, or maybe they are adjusted too tightly).  

I'm stuck.  Any help is greatly appreciated!  

No, never took the spark plug out.  I'll take it out to see if the resistance feels right.

Also, i just put a brand new battery in it.  pretty sure it's fully charged, but i'll throw a charger on it tonight to make double sure.  

I'm pretty sure the cam chain is lined up right.  i quadruple checked it.  Although, lemme describle what i did to make sure it's right:

I had both the left and right side covers off.  I turned the engine counter-clockwise until the TDC mark was lined up (it was exact).  then, i put the cam on with the lobes facing downward, and put the chain on to line up the cam so the marks were level.  (the marks could be level with the cam lobes facing upward too . . . but the clymer said to have them pointing down, so that's what i did).

Looked right.  

I didn't take the starter out, but when i had the cover off, both of the small gears on the left side did fall out.  i just pushed them back on.  they seemed to mess correctly.  i noticed marks on both of them.  I installed them so that the marks were facing outward, but didn't see any reason that the marks needed to line up with each other or anything.  Do they?  

Or, is possible i could have put one of the gear on backward?  Will they actually go on that way?

wow!  that sounds like it could definitely be it.

Gonna check that as soon as i get home.

Thanks!

Update:

last night, I pulled the left cover off to make sure the starter gearing was installed properly.  looks okay.

Then, I pulled the spark plug, put the bike in gear, and tried to roll it forward.  back wheel just slides.  

if i'm not mistaken, it should be able to roll forward with the spark plug out, right (no compression)?

So, i'm thinking i must have setup the timing wrong.  valves must be hitting against the piston.  

My question is 2 parts:
 1) is the starter strong enough to damage the valves and/or piston if i setup the timing wrong?  
 2) any other ideas of something i could be missing before i tear the freakin' thing apart again?

Thanks!