Again if you haven't done a compression check,that is one of the first things to do.Low compression can cause the hard starting or no starting problems. Gotta have good compression(along with good crank seals) good spark,fuel and air.

 

Evening,
Worked on this thing most of the day. Compression was good (110). Put brand new (freshly charged) battery on it cranked right over. Shut it down to out back together and would not start again. So, took battery off and put on charger and battery was drained? Put my other battery on, attempted to start and blew cdi box. Everthing I have read now says that I am dealing with a grounding issue. Tore whole thing apart and I see two ground wires. On that hooks to the battery and goes to bottom of motor. The other is on top of motor to the frame. Shouldn't there be a ground wire (to the frame) on the starter? Also reading that I could have a short in the switch box on left handlebar. Just seems there should be more grounds than what I am physically seeing. Thanks again

 

Battery ground to engine and frame to engine ground as you've noticed is on the motor mount. All the other smaller grounds usually terminate on the coil mounting bolt. Starter is grounded to the engine so no other ground is necessary on it. Again 110 is minimum on compression,plus you say you blew out the cdi? No spark now? Plus again if you get spark back and it still doesn't crank,try a shot of ether in the carb and see if it at least tries to fire up on that. If it doesn't then either compression is still a problem or a crank seal problem.

 

After placing the second battery on it, the only thing I could hear was the starter spinning. This is what happened prior to me changing out the cdi box the first time (after purchasing the quad) After changing it out it was able to turn over. As of now I have no spark. Think its about time to tear it down and replace seals.

 

If you just hear the starter motor only,the bendix could be just spinning and not kicking out to to engage the flywheel.

 

Ok thanks. Will check that out when I start pulling things apart.

 

Removed the engine today and have ordered parts to repair. Rings were shot on the piston and the gearcase did not even have a gasket on it. So, since I am taking this thing apart and rebuilding, thinking of removing the oil inject and blanking it off. For those that have done this, I have read that some remove the gear and put a "blank" gear in and then a blank plate. Others have simply pulled the gear and blank plated over it. Having problems finding "blank" gear to fill the space. What is best? Thanks

 

The "gear case" or engine cases don't have a gasket. It uses Three Bond,Yamabond or similar product to seal the cases.Have the cylinder measured and bored out to the next over size piston and rings. Don't just install new rings on an old piston.Plus check the rod and crank bearings for any wear. These pumps are practically bullet proof on the 250 engines,but if you want to go to the trouble of premixing,you could leave the pump in place,drain the oil tank and cap off the injector nozzle at the cylinder base. If you want to remove it entirely,this place has block off plates,single throttle cables,etc. Aaen Performance - Polaris ATV Two Stroke - Top End Pipes

 

Thank you for the info. Just want to make sure that after the engine rebuild that the pump does not go out and blow the engine. I have read that some people have had this happen and others have had no issues.

Thanks again

 

Some early 300 models yes along with 400 oil pumps simply because they were located at the front of the engine and could freeze,rust up from water. Most people waited too long before they had a new top end done and when disaster happened,they blamed it on the oil pumps,not themselves.