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By John Victor
My father-in-law gave my boy a 1999 350 Big Bear. It's been sitting in a barn for a bunch of years. It runs great! My boy has been riding a couple weeks now and it has developed a squeal coming from the front end when you get off the gas at speed. No noise during acceleration. At first I thought brakes. I took it for a ride and I don't think it is the brakes. I feel it is the front prop shaft U-joints, front differential or one/both axles. I pulled the fill plug on the differential and I can't find anywhere how much gear oil should be in there. My gut says up to the fill opening. It doesn't have a manual. It's wet in there, just don't see any gear oil.
#1 Should I fill the differential with gear oil up to the fill opening?
#2 How do I check or know if the u-joints are bad? That looks like a "Big Bear" of a job if they don't need to be replaced.
#3 What else could it be? I don't think it is the front bearings. I jacked the front wheels off ground and no play in the right wheel. Very little play in the left wheel, looks like the lower control bushing is where that play is coming from. The rubber CV boots look original but all still intact. Wheels spin easily without any noise.
Thanks for any help!
By Dra O
posted a while back - it was running at one point - I have all the plastic shroud off - it's down to frame and engine now
-fuel pump: when line from petcock is attached, no fuel comes out other side to carb; the line to the carb is open (can blow through it); I thought when I cranked engine that the pump would spit out fuel on other side but it does not; I removed fuel pump and opened it up - diaphragm looks good - but internal areas had lotsa calcification build up - I cleaned this out and dried it good - the clear plastic pieces (?diaphragms) aren't broken - the spring w/ steel ball on end moves freely; am putting it back on tomorrow; but can anyone answer about the pump? isn't it supposed to pump fuel through it... to other side... to carb? puzzling
-along with fuel pump: I replaced petcock 3 weeks ago (gas tank had rusty fuel in bottom - cleaned it out prior to new petcock); when I turn petcock arrow NOT to on or reserve, fuel comes out of line; when I turn it to on or reserve, fuel doesn't come out; puzzling
-I don't know what's on back of fuel pump - it's a valve that has a hose coming out of it - looks like it goes to engine/carb - I haven't traced this out yet - what is it?
-can squirt gas on air filter and engine will run for 2-3 seconds then stop - fuel in top of carb (under diaphragm) does same
-it likely needs carb rebuild - will get to this - but something isn't allowing fuel to get from fuel pump to carb
-I THINK it has a mikuni model x carb - diaphragm is ID 26mm OD 68mm - hard to find inexpensive diaphragm, I guess because it's a model x
-last thing - I replaced solenoid due to old one clicking; I HAVE to be charging the battery or it won't start/turn over - battery just goes dead; but if charging, it'll turn over nicely; i'm guessing it's a bad battery
-any help appreciated - I've never owned an ATV before - inherited this beast from grandparent in-law
By pablo Blake
Its in pretty rough shape and its gonna be my first atv, I worked on bikes before but nothing to do with quads. Anyways the quad has some problems and im tryna figure out what to focus on first. So the U joints i think are shot. The bike starts first try every time ussually have to give it a lil gas with the throttle and revs right up, idles fine but its running REALLY rich 3 starts and my brand new plug was pitch black
Bike is L model
Its using the original mikuni carb but im not the best at fixing the carbs and wondering if there is anywhere online that would be able to either walk me through it or help me with it i didnt see a air mixture screw so it seems like im gonna half to open it up and adjust like the float and a couple other things
By Dee Morris
I bought my big bear in 2009, never had a bit of problem with it until last year. It quit starting but still would click when I tried to start it. I replaced the solenoid, the cdi module ( it was burned on one corner) and this year replaced the battery. I have all lights but still will not start and I do not have the clicking when I try to start it. Can anyone give me any ideas what to try next? I haven't had any luck finding videos about the 2008 Big Bear. I'm trying to avoid the expense of sending it to the shop.
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By Christopher Williams
i just rebuilt the top end of a 99 Bear Tracker 250 and it can’t get it to hit off of gasoline or starter fluid. Occasionally it will backfire. Right now I’m just trying to get it to fire off without the carburetor like I’ve done a thousand times before with other engines. Usually there is no response, but occasionally I get a backfire through the intake. ISeems like it’s out of time, but I don’t see how that could be possible.
Here’s what I know:
1. compression 120psi
2. all timing marks are lined up after numerous revolutions.
3. Strong spark.
4. Valves adjusted correctly.
Thanks in advance.
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