Recently got a 2000 big bear 400 that needed a few thing( brakes, the carb backfired, and it was in rough shape in general) well the night I got it it ran fine, just a little back firing in the higher rpms. Then i had taken all the plastic off to fix a wiring issue, the previous owner had wired the fan to a switch and it had stopped working, come to find out it was a bad ground).

Once I got it back together the next night it took 5-10 minutes to start. Then it started running fine till it ran out if gas that night.

Well now it's not starting, it's a good spark(blueish white) and and getting gas( you can pull the plug and smell gas on it) so I pulled the carb cleaned it up some. It looks like it was recently rebuilt) I fixed the float level since it was off and everything else looked ok. When you try to start it with starter fluid it will backfire some out of the carb.

So I have no clue what it is.

FYI: the previous owner had the pilot screw turned all the way in, in guessing because they had the float level so high?. Also I changed the spark plug and the old one was black and sooty. When trying to start it, it would grind. Come to find out now that it's the starter clutch bearing that makes that noise I believe? And that it could cause it not to start.

The only other thing I can think of is that it jumped time?

Thanks

 

No one has any ideas?

 

black with soot spark plug indicates is running WAY TOO RICH. that needs adjustment.
you said you cleaned the carb some. What? if you ran out of fuel, it is possible that some solids/debris got past a fuel filter and plugged a jet. really clean the thing.
starter issues? sorry, not my forte.

 

I would check compression..prolly an tight intake value....Alot of time the air filter as been bad an this will let dirt into carb to intake port an sand blaster the back side of intake value, If its has an new air filter then there your sign of an bad air filter before..Good compression should be 120 to 160 pounds.

 

Ya when I bought it, it had a new air filter. But would this make it not start all of the sudden? And how do you readjust the valves on it? Is there a write up or instructions somewhere? Or will it be in the FSM?

 

Here is a video on how to adjust the valves. The 350 is the same motor as your 400 but with a shorter stroke. May want to make sure the valve clearances are the same.
Part #3

 

Alright thanks!

 

I had same type of issues with my big bear 400 few years ago. mine would backfire while trying to start and make grinding noise. I had to pull leftside crankcase cover off and found woodruff key on crank broke and spun around and caught again on itself. this made the timing off slightly which lead to backfiring and not starting. Also one of my idler gears for starter broke couple of teeth and had to replace that. If u decide to fix this yourself, I would advise you to get manual. I had haynes manual when I did it and was very helpful. You also will probably need flywheel puller to pull flywheel off crank, even though woodruff key was broke still needed puller to get it off. You might not need it but mine wouldn't come off without it. Once you pull flywheel off there is one-way clutch on inside of flywheel, check and make sure that it spins freely in one direction. If it doesn't then that needs fixed or replaced. Mine was stuck and it cost a good bit to replace. The dealer told me I had to replace it along with many other things totaling $500. I was able to get clutch out and stuck it back in and has been working for 2yrs now. I don't always believe what they tell u. I just bought new woodruff key and idler gear for under $50 and all is good now. I hope this helps you out and keep us informed with progress. Im not sure but your situation sounds alot like mine was doing. Good luck and if I can assist in anyway just let me know.