Could you direct me to somewhere that would tell me how to find that needle you mentioned in the first suggestion? I think that's my problem, because my spark plug is pretty much black. I bought a new plug and I think I just need to adjust that needle, but I can't seem to find it
I think you are probably right about it being the carby. I will tell you how to fix it but I'm sure there is a thread showing how to dismantle and reassemble the HT Carb. Try searching for a thread using "HT Carby"
To change the needle setting you don't need to even take the carby off the bike. Just loosen the carby on the intake pipe and turn it towards yourself for easier access.
Then unscrew the cable holder at the top of the carb and the cable, holder, and grey cyclinder with needle will pull straight out of the top of the barrel.
Remember that it only slides back in if the cylinder is lined up with the little air/fuel mix screw. It's easy if you look inside to see and look at the cylinder itself.
Don't drop anything and pul a white towel under where you are working in case you drop a small washer or spring.
You will see that the cable end slots into the cylinder quite easily - to remove it you just depress the spring and slide the cylinder up so the end of the cable can be pulled out and off the cylinder.
At the bottom of the inside of the cylinder is a little slotted washer (DON"T LOOSE IT) and below that is the needle and with C-clip attached.
Turn the cylinder upside down and both will drop out.
You will notice 5 grooves (sometimes 4 grooves) on the needle and the C-clip will probably be on about the third one up from the pointy end of the needle.
Pull the C-clip off using pliers and push it back onto the lowest groove (that's the one nearest the pointy end of the needle) using the same pliers.
Wipe the needle clean and drop it back into the cylinder pointy end down. Then drop the round slotted washer in and get the slot to align with the gap in the wall of the cylinder.
By depressing the spring with your fingers you can slot the cable straight back into the cylinder and let the spring expand back down the inside of the cylinder.
Put the whole unit back (don't forget the cable barrel holder that you first unscrewed cos it holds it all back in place) taking care to slide the needle and cylinder back down the carby barrel the way it needs to go so the little groove at the bottom lines up with the air fuel mix screw and the gap lines up with the tiny brass screw you can see sticking out of the inside of the barrel.
Screw the top back on tight and turn the throttle grip listening to make sure you hear the needle and cylinder moving freely in the barrel. Then turn the whole carby back upright on the engine intake pipe and tighten it using the clamp screw.
I reckon this will solve your bogging problem. Let me know if it doesn't.
When you get practiced at this the whole exercise takes about 3 minutes and is actually very easy.
If this doesn't work we'll get youto clean the other needle valve but it probably won't be necessary.
Oh yes, you must have a good fuel filter installed between the tank and the carby and stay away from Ethanol fuel or dirty cheap fuel of any type.
Good luck.
