1964 Honda c100 starting problem ( re posted with better info)?

Right before I start this is a repost I didn't put enough info in and accidentally posted it early. I was given this bike. It had been in a shed since the 80's I managed to get it running (rough) I then began restoring it. Focusing on the engine and carb now. All bearings and gaskets have been changed replacement carb was ordered (second hand) as the choke valve was broken. Carb was cleaned and replaced what parts I could. Put new piston rings on piston wich measured ok. The top end was wet blasted and re-painted (bore was plugged up) valves cleaned and re-seated. Then back together and the valve clearances were set. The points contactor was set and a new exhaust was purchased. Now I can't get it to start. I have since changed the point contactor and still the same. Best I can get is a very slow lower than tick over splutter for about 20 seconds with the throttle and choke open. I have tried the old carb, same thing. I have checked all timing marks valve clearances contact gap. Also after taking the exhaust of there was black gunge in there. So being concerned I took the head apart and rebuilt replacing all but the head gasket (original one as the new one is a bit pricey). But I had no reason to believe it to be bad. Still the same. I machined my own headgasket, that's the same with same results. Its driving me crazy. Broken 2 kick start shafts with constant kicking over. Tryed original spark plug and a new one. Anyone got any ideas.

I'm not sure how I can add more info other than via an answer, when I set the valves I noticed there's an ammount of play in the inlet valve as I can move the rocker up and had to do this to set the gap. The exhaust valve barely moves atall mayb .02mm. Were as the inlet mayb 1mm. I'm now assuming that mayb this is the problem? If so wich part is sugested to be at fault? Also assume the rest of the bike is like new as most of it is now.

I don't think you have a valve problem but do a compression test to be sure. That will at least tell you if there's enough compression to get it to run. You said it does barely run for a few seconds but then stops. That is why I say not a valve problem. I'm thinking a fuel problem. It might be a fuel supply to the carb problem. You do have a very old bike and there could be rust in the tank blocking the fuel line. Take the fuel line off at the carb and run the gas into a gar it should pour right out.
Being old you might want to add if it is a two stroke or four. There could be crazy things like the wrong type of bearings on the crank if it is a two stroke, they need to be sealed bearings.

It's pretty hard to get the cam wrong on that engine, but make sure it's timed right. Never re-use an old head gasket. It will not run without a battery.

Number 1- The fuel system is clogged. That old of bike has years of fuel-varnish build-up in the tank, that varnish gets dislodged into tiny flakes, especially if adding E-fuel (the alcohol in the fuel melts the varnish). Install an in-line fuel filter AFTER the tank/petcock has been thoroughly cleaned.

Make sure the 6V battery is FULLY charged, a weak spark is like kissing your fat Aunt Betsy, its not going anywhere.soon.

The C and CL 100-110 are pretty strong engines for their size so keep at it.
You may wish to visit an online forum for the CL110, which basically is the same as your C100, there are plenty of CLs out there running (they are motor-home need-bes).

So how does the spark look?

If the valves aren't moving perhaps the valve guides need cleaning/replacing.

But for the black gunge in the exhaust is it oil residue, if so it might be oil getting past your rings have you positioned the rings correctly, did you replace the o-ring on the cylinder head?

http://www.mopedarmy.com/forums/read.php?6,1822667,1822746#msg-1822746

Best thing to do is to join an owner's club - there are millions of Super Cubs there must be hundreds of clubs.

Try this guy he knows bikes