So...if you haven't figured out the running issue I'd suggest pulling the carb and inspect/rebuild. It looks like a CV (constant velocity), but I could be mistaken. If a CV, it has a rubber diaphragm in there that could have issues or it just needs a good'ol cleaning. Not sure what your experience level is on such things, but that quad has been around for awhile so there should be plenty of "how-to's" on the net...

 

True. Even on some stuff I've done a few times, I've looked over on youtube to see if someone else has found a few short cuts that I haven't seen.

 

I did clean and carb and it seemed like nothing was broken so I didn't replace anything and just put it all back together. We then preceded to try and start it up, We then discovered the fuel pump/fuelshutoff thing on the bottom of the fuel tank is leaky and dosnt seem to be working well at all, Disheartening because that part seems fairly expensive and it also seems the some of the seals in the crankcase and/or starter have failed because it started spewing gas and oil when we got it started (used ether). Going to replace those seals and see how we are doing. (also going to need a new oil filter among other minor things.)

 

Ah...the joys of buying used!! It's a great learning experience!!

 

Ok after a few weeks Im coming back to update This thread (and make a new one About future Restoration/Mods.)

It took a rebuild of the bottom end, a new Swingarm bolt, A-arm and Front wheel bearings and seals to get the bike running and able to drive. (cost ~175CAD)
I then drove it to discover that the front breaks dont work over running speed and so engine breaking (Which is awesome on this bike thank goodness) is all I had, drove it like that maby 3-4 hours a week for two weeks on private property to get the feel of the bike and see what else may be wrong before I started working on it again.

Going back to the lack of stopping power Issue Im considering buying a back break but I would need line rez and caliper so if I dont see a good deal I wont grab it. Ive just ordered an entire front break system (Calipers lines and rez) for the bike off Ebay having tried every conceivable thing to the ones on the bike to get them to function. The first thing I tried was bleeding the breaks, after that didn't work I elevated the calipers higher then the rez while bleeding (worked on my friends Dune buggy when he had this problem) and then after that didn't work I started making sure the pistons weren't sticking, checking the pads for ware and making sure rotor alignment was good. After all that checked out I am stumped and just decided to order parts online, Im hoping that will solve this specific problem.

Ok so before when the bike was running it starved for gas starting at half throttle and got progressively worse as you gave it more gas resulting in a loss of power although you would still accelerate.
To fix this problem I replaced the Fuel petcock (which would leak slightly after use), fuel line and filter (the previous owner was using lawnmower parts from Canadian tire,) and I gave the carb another good cleaning as I had it most of the way apart apart anyways. I replaced the Fuel petcock with an OEM part I found on Ebay, some standard black fuel line and a high flow fuel filter from a 2005 Ninja636 as we could not find a part with listed compatibility so I figured hey its just a tube with a filter in it as long as its got enough flow rate it should be fine. (my friend even suggested I grab a small marine filter and I would have but it was double the price and glass so I didn't know whether or not to trust it and went with the safe bet.)
I go to turn the bike on to make sure its working annnnd it cranks, and cranks, and cranks but wont turn on. So I know you need four things to turn on a corroborated engine: air, fuel, spark and compression. Assuming its a fuel problem I look there first, at a glance it looks to be working so I check the other things. Skipping the long version of this story I ended up having to use ducktape, a socket and friction to get the spark plug out just to find out that it was fuel in the first place. Im sure those of you who are more experienced then me know already what happened, I had checked the flow of fuel at the carb and at the petcock when both were fine I moved on but the problem was some air in the fuel line causing a vacuum effect stopping fuel from entering the carb. The fix? fill the line with fuel 100% and then connected it back to the fuel petcock making sure not to let air in.
After that the bike works great, runs smooth sounds better and revs much higher. The loss of power is also gone and the resulting torque rather then speed caught me off guard, running most bald tires wheel spin was already a bad issue but now? Oh man on anything but hard pack or pavement its drift city.

 

I think the oem petcock on those has a "prime" position which is somewhat unusual on a sport quad. Sounds like it may be necessary based on your described issue, so a stock petcock may be in order eventually. Glad you figured it out!

 

Ok so Same bike, brakes are working good now but it has developed a really bad air locking problem and I'm not exactly sure how to fix it.

If I leave it for more than a few hours it airlocks and then takes a good few min (usually 3-5min of turning it over if I leave it for a day or two, glad I have a good battery) to start as it has to pull the air though again, the only think I can think of to fix this is to like coat the fuel line connections in silicone or glue or something like that.
Im not sure if its related to the fuel locking problem but the bike will also stall at idle whether its warmed up or not and it does not seem to be consistent either which makes it very hard to diagnose.
It starts up no problem so long as you dont leave it longer then a few hours, not sure if this is due to the temp of the engine or just how long it takes the air to seep back into the line. Maby a bit of both but after those few hours pass it takes a good few turns and gets worse from there.