Have an 1999 Big Bear 2wd..Friend bought an aftermarket CDI.and was wondering if yal have had any problem with some of them having problem with them causing Ignition to be out of time? If put an timing light on"F" mark an when ignition fires the "F" mark isn't there...Atv wasn't firing before the aftermarket CDI was installed..Fires fine now but when put plug in head ready to start up sound like igniton is off an causes engine lock down...Sometimes with the timing light on to check spark seem like its skips afew rounds before fires again...It does this while under an load..ALL ignition parts..stator,pulser generator all in specs.Has new starter,new OEM starter clutch spur gear and one way already installed because one way bearing went out an broke gear tooth off spur gear,also ate up starter shaft splines...Thanks in advance

 

Not that familiar with the Big Bear,but sounds like what an engine would do if timing is too far advanced. Ignition as the piston is still traveling upwards. Can cause one to lock up as it's fighting against itself. Has the stator been messed with or is this stator adjustable or fixed. If not the stator then possibly it's the aftermarket cdi itself?

 

Thanks OPT...No the stator is OEM...Never been messed with. and stator is fixed not adjustable....One owner atv..

 

Check that the flywheel has been put back properly and that the key is sound. I have had a Suzuki flywheel come loose and broke the key, altering the timing. It would still fire at F though as the F mark and timing sender are both on the flywheel. Any broken bits stuck to the flywheel or hit the pickup coil?