How do I  check to see if the  carb float level is correct on a 1969 L5T Trailmaster? 

Greetings from Tennessee  
That’s a great looking bike!!

THere 'is a measurement with it lightly sitting on the spring loaded pin in the center of the float needle. I'll go look for the measurement. But i'd be VERY worried about the squashed float. If it floats in a bowl of water it'll be ok. I've had bikes running on one float. Shake it to see if fluid inside. Might rattle with solder but won't be much.
 Ok, nearest i can find is the road going version but i think your carb would be the same 18 mm carb venturi size [they list a 20mm carb too but same float level]. So float level as it happens is 17.9mm--say 18mm. Looking at the pic it looks too high [looking inverted in the pic] so too low i fact--not enough fuel in the bowl. From what i can see of the arm angle at the needle valve it looks best to push on the arm surround to get the surround & tang on an even plain. Then might need to bend the floats up to get your 18mm level. Only saying 'that' because on the far side it looks like the float stop [when inverted corectly & float drops] is just about touching the post, so the way it all looks is that fuel will be about shut off with that stop touching the post so very little fuel will get in before it stops flowing. I'm overcomplicating it all sorry. tell us the story--what's been going on in there. Ignore my complicated woffle if ya happy with things as they are as i guess she was running.
Also, should measure from the carb body to the float with float tang lightly touching the spring loaded pin in the needle, not compressing it.

might be a little wrong in reference to angle of the tang. Check ebay number below to view a new float. Or even to buy it, cheap enough if you need it. I'm no good at linking Ebay direct so hope number comes up. Has good pics at all angles.
eBay item number:184417984551
ok that doesn't work for me putting it in search bar. [& now it does, just me i think first time].

WOW! thanks for the reply. Idid check the floats for leaks and they are sound.  also noticed that the tang is not flat against the needle, is that a must before checking for 18mm?
Maybe you can help me with another issue. Can you identify this part? I found it in a bag labeled schock and muffler parts. I have looked at parts break downs for both the frame (shocks) and the exhaust and don't see anything similar. It might not be for this bike.
Thanks
Brian

That looks like the seal from exhaust header pipe to cylinder.

You're right, I just installed it. When I first looked at it I thought that it might be a header gasket but when I looked at the parts diagram it did'nt show.
Thanks