TylerP

Older bikes are prone to leaky intake manifolds. You can check by spraying something flammable around the manifolds and see if the engine reacts to it. Contact cleaner works good.

The factory puts these in with Loctite so they can be a pain to remove. Here's what to do. Get an 3/8" air impact gun and an allen socket the size you need. Heat the bolt about a minute with a propane torch. Have someone pull the inner tube out while you pull on the heated end and with the bolt with the impact gun. Sometimes you dont have to pull the forks apart and the bolt will come out. I have also used the fork spring to hold the dampening rod while I remove the bolt.Just turn the fork upside down with the spring in it and mash down while you use the impact. An air powered impact gun is THE way to get that bolt out. Be sure to reapply some Loctite to the bolts when you put them back in and watch for the brass washer under the bolts when they finally come out.

Are there any restrictions in the air intake? Could the fuel level be to high? If it has brass floats make sure they do float. Air mixture screws? Are you sure they do not control fuel? If the screw is on the engine side of the slide it controls fuel and they will be open way to far. 2-3 turns out from bottomed should be close.

They handle ok. Vibrate pretty fierce. They run good but need jetting work to run better. About as reliable as your going to get. Be sure not to run it with the air filter gone!

Those numbers dont sound familiar to me but if it has a .50 on top it should be 1/2 mm over bore,or 70.5mm. A 70mm piston will be to small now.

Is water getting into the air filter somehow? I would start by unplugging every electrical connector and applying some dielectric grease in the plugs and plug them back up. Also make sure the plug caps are not shorting out in the wet conditions.

If the black wire coming from the points is grounded anywhere it will not spark. It could be grounded under the flywheel to.

An impact gun will buzz the main nut off. The other screw is held in by the lock nut on the outside. If it's stuck you may try applying heat to the case.

What year Firebird does he have!

You mean like thru a clear fuel line or fuel filter? As long as the carb gets fuel it wont matter if there is air in that.

You dont have a Yamaha dealer near by? My job ships out daily. www.leesinc.com

Hoe about using a multimeter and checking the charging output?

Good luck finding a condenser! No longer available @ Yamaha and neither KK or Parts Unlimited carries anything. I ended up enlarging the hole where it fits in and used a Suzuki condenser with success. I had to do a little soldering but it got the bike running. Point gap should be right at .013".

Never heard that one before. All I have ever seen are a straight slot or are fixed and wont come out. Use a jet cleaning tool and run it thru the hole in the jet while it's in the carb. At least you can still get it clean and you wont chance damaging anything trying to remove it.

Some bikes do idle up high with the choke on. If the motor is warmed up the choke needs to be off anyway.