If it turns over fast it is not the battery or charging system. If it turns over fast but does not like to start when motor is warm it is probably running rich. If it ran good before and the carb has not been messed with i would check the air filter. It needs to be nice and clean.
if the o2 sensor is still in the pipes , it is ok
if not have the adaptor fitted to the pipes and it will be ok
the sensor reports the gas composition to the ECM to adjust the air/fuel mixture
if the new pipes are pollution control compliant the adaptor should be already there
if they are not then you are achieving nothing with the different pipes but are actually decreasing fuel economy
Try taking a look at the starter and flywheel while attempting to start the engine. Does the small gear at the end of the starter move forward and engage the flywheel when you try to start the engine? Could it be stuck? The small gear must move forward to engage the flywheel. Keep your fingers away from the moving parts.
Your 4 wheel drive may be working, but it is a torque-sensing front
differential for reduced steering effort, that supposedly sends power to the wheel with the most traction. Many owners have found that just the opposite is true. Your problem may mean that the differential is working, but because it doesn't lock up both tires in the front and only one tire is getting all the traction you can't see it work as advertised. The link to the video is great for showing what may be happening. The front differential may be worn out and need to be fixed or it may just be that it is not working as you expected:
https://www.youtube.com/watch?v=KF-iD4pmmoA
Sounds like it may need some carburetor work. If you've stored it without any fuel stabilizer added, mixed well, and ran through the carburetor a little, even for as little as 30 days, the fuel can break down and leave deposits on the small mixture jets inside. Spraying some carb cleaner while starting and running will sometimes loosen up those deposits, but more often than not the carb will need to be taken apart and cleaned.
You need to first determine whether the problem is fuel or electrical. Remove the sparkplug and pour in a small quantity of gas. Replace sparkplug and high tension lead. Crank it over. If it does start and run a bit then your problem is fuel and not electrical. If it does not fire and the sparkplug is wet, then start be replacing the sparkplug with a new one.
Take the float bowl off the carb. Pull the pin that holds the float on. The needle is attached to the float. The needle just came out of the needle seat. The needle seat can now be pulled out. This is the fun part. Are you really sure it need replaced? If it is needing a good cleaning, take some Mother's aluminum polish and a cotton swab and put it in the seat and spin the heck out of it. It will polish up nice. Be sure to clean with carb cleaner to get any extra polish out before use.. reassemble.
btm is neutral .all the way down i believe. all up from neutral position pull brake lever and push button to put in reverse ? from neutral pos. reverse is past neutral only gear lower than neutral is reverse
Sometimes you need to adjust your clutch cable. as the disks wear out you have to tighten it to get it to disengage. if the cable is adjusted too tight then it will slip because it is not taking all the pressure off the disks so they can fully grab. That is where i would start
