Engine had an air leak so I tore it down and replaced the case gasket, seals with double lips and the leaking homemade base gasket with same thick black felpro stuff as the previous one that worked fine before leaking. I replaced the head gasket too but it didn't like that one and just huffed and chuffed and blew lot of air at the carb. Actually amazed it started with that giant gap. The head has a 2x2mm ring that presses into the gasket (I'm guessing here, not going to pull head to measure or take pictures at the moment) so I looked at the old one and put it back on with the high side on the intake side and no more huffing and chuffing. Ran it a few times and re torqued the head bolts after cool down and each time it wanted more idle screw. The hotter she got the more screw she wanted until it was all the way in and had to resort to the throttle cable adjuster to raise the slide even more. The only thing out of the ordinary is the amount of throttle it wants to idle. I can tune it like normal, I can get it to four stroke or two. Removing filter makes no difference and full choke still kills it and partial didn't seem to do much at idle. Gonna have to try partial choke under load but thats a pain on an NT carb so might have to rig a handle bar control, I have before but its a pain too. Sprayed some carb cleaner around it and no change other than it dying when sprayed near the carb, though not really sure it didn't just die on its own since it wasn't an immediate response. Will try that again when not raining and a different plug, have a 7 in it and should have a 6 and a 5 around here somewhere (numbers refer to NGK heat range). Also has no power over 25-26mph was 30-32 when I had the air leak but would probably be higher if the clutch wasn't slipping and no not from a seal leak. I think the hole clutch is moving left to right a few mm, so when it gets up there it starts moving back to the left and pushing in the bucking bar a bit making it slip. New gasket was pretty thin and didn't pay attention to the old case gasket thickness but the problem existed before changing it. I tried 3 different internal clutches, 3 sets of pads and 2 sets plates. Even tried a new spring since the other 3 were old and sat for 4 years or more in light states of compression since they were assembled. No mods other than an old SBP expansion pipe. I've got ideas on the clutch but the idle has me stumped. Engine is mixed Dax lower and BGF upper. I messed up the case on the BGF so figured why not get the balanced lower. Both are 40mm rods and I cant remember if the piston was an A or B but I'm sure its the correct one. Its been years but I'm sure it ran fine before the air leak. I just took it off the my Delmar after I got my trike going then starting building my 62 Corvette shifter but that got stalled and buried for a several years. She came out the factory a 5spd was a single when I got her and now shes a 7spd with motor.