I just finished having 250 bored out and new piston rigs, replaced both both crankcase seals.
I was trying to free the bolt and nut for clutch arm and was unsuceesful. Is that a reverse thead? I removed it from the left case and tried to break away the nut and screw. 

the other issue is i start it after i rebult carb and it only likes to run with the carb choke on. could this be the idle jet? it is clear and no blockage. I wouldnt think it the main jet issue. Any suggestions? on other thing i noticed when i sprayed starter fluid at the base of the head it would stall. i put new cylinder gasket and head gasket when i bored it out. i even rechecked the torques.

Any help or suggestions would be greatly appreciated.


 

Better totally dismantle the carb right down to removing pilot & also the needle jet 'emulsion tube' where slide needle runs.
I had stale fuel residue grow up inside my needle jet but had sat fpr a year or more & our fuel is rubbish.
Remove main jet from the holder as stuff can get behind it as they flow in reverse in the jet holder.
Don't forget that small Oring on the jet setter that seals into the bowl although your problem is opposite to 'that' leaking & would be rich if leaking.
Not sure about stopping when spraying engine start at the 'base of the head'--just stop spraying it i guess but sounds like ya looking for a leak.
Unlikely for the head to leak although i grease mine on assembling & also the base gasket. If base was leaking i'd think you'd see it looking like it's leaking or sucked in--or sticking out.
Set idle mixture at 1.5 turns out, but to prove a point could screw it lightly fully home to see if it richens the idle or has no affect.
Above idle speed everything comes through the main jet to get to the needle jet which is why i said remove the jet & look behind it.
Could lift the needle, "clip down" to richen it up but main jet inspection is important first. Sorry i do go on a bit lol & probably forgotten something--manifold leak etc.

The clutch actuator adjustment nut and screw are not reverse thread. The nut can become frozen and difficult to remove. It's easily damaged if you put it in a vise. Also the nylon spiral is likely to be cracked if it's original. I use a cordless 1/4" impact driver while securing it in a vise wrapped in a rag. I also have newly manufactured actuators with new old stock screws and nuts.

I've been lucky not to damage anything by just forcing it at the limit which is probably either pushing the pressure plate into the clutch cover or coil binding the springs but worked for me. I've also turned it out & carefully grabbed it in the vice on the piece that the cable pulls, just grab across the centre & push down while turning to stop it jumping out of the jaws. It'll crack free. Other way I only just thought of is, pull the pushrods out but first measure the rod overhang & place a block of wood in there & tighten cover. Then actuator has nowhere to go moving in so has to crack free. Yep that'd work, forget my other ideas lol.