Hope it last for several more years now..

 

One more question...... is there a good starting point for the carb adjustments? I have a larger spring loaded screw that is a phillips bit and a smaller flat head screw to the bottom left of the larger one. I have looked online and it seems to be all over the place.

Also, can you recommend a mix ratio? Im thinking about running mixed with the new top end just to keep things safe

 

Always run a tank of 50-1 premix on breaking in a new engine even if you use the oil pump also.Will smoke a little more than usual. Same as what Polaris recommended on ones straight out of the crate. The small screw is the air adjust screw, normally around 1-2 turns out from a lightly seated position. The big knurled screw is just the idle speed adjuster. Turn it to where you have a steady idle,but not too high to where you have gear clash when you shift.

 

Awesome! Thanks again for all the help

 

Man...... There is a little barb fitting on top of the case behind the pull start. It looks like a vent to me. I went riding some trails this afternoon and noticed stuff coming out of the barb fitting that smelled like antifreeze. Please tell me there should be a hose on that barb fitting and not that the head gasket is leaking!!!!!!!

 

Looks like your work isn't over yet.. This fitting is the counter balancer cavity vent and yes should have a hose on it that terminates under the tank area. Counter balancer only holds about 100ccs(3.5 ounces) of 30 weight oil. If coolant is pouring from the vent ,the water pump seals are leaking coolant into the cavity. It can be repaired with the engine in the frame,BUT the cover is hard to work around the frame down tube because the inlet cooling hose nipple hits it. Flywheel,stator,water pump impeller,plus outer case need to be removed. Item #38.Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse
Water pump seals,case seal,bearing and gasket have to be replaced.Hopefully the counter balancer shaft the seals ride on hasn't been corroded by the antifreeze. Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse
The manual is really helpful on water pump seals and bearing replacement.It is important not to block the small hole in the water pump housing when installing the seals and bearing.

 

Dang...... Do u think I did something when I pulled the cover and checked the woodruff key?

 

Nope,the water pump seals/housing is behind the stator and outer cover. Common problem on seals leaking on the 400 2 stroke.

 

Good deal. Time to order more parts

 

Don't forget to order a new gasket for the outer case. Hard to reuse/save this one. I'd tear it down before I ordered the parts.IF the counter balancer shaft is corroded,a couple places on ebay that can repair them along with replacing the big bearing behind the counter balance if needed.http://www.ebay.com/itm/Polaris-ATV-400-350L-counter-balance-shaft-water-pump-REPAIR-balancer-/300941567648?pt=Motors_ATV_Parts_Accessories&hash=item461183e6a0&vxp=mtr