So my brother in law has had a polaris 250 2x4 sitting in his field for 8 years, not running once in those 8 years. Ive taken the whole atv apart to clean, repair, repaint etc but I am trying to get it to run before putting too much time into it. So I know where the fuel line goes into the carb, then you have a the black 90 degree elbow that points straight up ( this is the breather...correct?), then you have another black plastic fitting on the bottom that is the float overflow. My question is.....if you look at the intake port, there is another brass tube that points to the right....is this an oil feed line or is this another breather/vacuum line, ive been told both and trying to figure it out so I can get it running. If someone could verify what I have said I would greatly appreciate it. Thanks

 

Just have a tube at the bottom of the carb bowl for the overflow/drain. Both openings at the top of the carb are vents. Just run separate vent lines,run em up along the throttle cable/choke cable,zip tie em on the cable and let em tuck under the tank. Good luck on getting this machine running!Plus here's a couple of videos on Mikuni carb cleaning.

 

Thanks for the quick response and thank you for being on this forum as you seem to know everything about everything. If I spray gas in the spark plug hole on the compression stroke it does fire which is good. Im gonna try the starter relay test tomorrow, the BMC needs rebuilt, and I should probably do a compression check as well but I dont want to dump a bunch of $$$ into it just to part it out.

 

Sitting in a field for 8 years is hard on all parts especially crank seals if it had any gas in the tank or crank case during this time.Plus even hard on them if it didn't! I'd definitely do a compression check before I sunk any money into it. If it's 100 psi or lower you'd be wasting your time if you don't plan on restoring it..

 

Checking back in, and the news....is not good. The compression on the third pull was 110 PSI which was surprising, but I failed to fix the carb and the engine still wouldnt fire, I took the head off and got a nice surprise as the piston has been melted and is no longer a perfect circle although enough so that the piston rings can still hold some compression. There is also slag melted to the piston head and what looks to be like a piece of metal protruding from the bottom through the head and is sticking out. SO....right now im deciding on whether to rebuild or scrap, and the rebuild would be full as it needs a new starter, brake system, engine parts, gaskets, carb items, and idk if the tranny is any good yet either although it does move freely. I do have the budget to rebuild but just not sure yet.

 

Hardest part is having a new rod kit installed and the crank trued up along with the cylinder boring.A good machine shop can do this if you don't have the tools.It's a fairly simple engine. Hot Rods are one of the best and reasonable rod kits I've found along with Vesrah. I've used them both a lot over the years.Plus I'd go with a Wiseco piston if you do decide to rebuild. Good luck!

 

If I have it bored out, what would be good 72.5/73/73.4/74? or does it depend on the performance I want out of it? Also would I need to up grade carbs or just upgrade the jets?

 

Don't waste cylinder bores for a few ccs increase. Just have the cylinder measured to where the cylinder will clean up whether it's first over,2nd over or whatever.

 

Cylinder is actually pretty clean and smooth but i will see what they can do. Just asking, but if I rebuild am I just dumping a bunch of time and money into something that will never run? I dont want to waste either and would like this to be about a 500$ build which can get alot done actually but I want it to run and not sputter, or is it all just chance?

 

You could be dumping money into if you don't rebuilt it completely! You'll spend more doing it right,but if you intend on keeping it ,it would be worth it. If you buy the parts,have the rod installed,cylinder bored,new bearings,seals,gaskets,carb kit and you put it back together,then yes around $500-$600 should cover most of the engine,but other things could be needed on a machine sitting in a field for 8 years such as a new drive chain,axle bearings/seals,suspension parts,etc,not including tires?. Any old machine can turn into a money pit.