carguydave

The chain tension is correct, and it rolls fine in neutral.  Another weird thing I found today after I took the belt off and put it in gear is that it will roll with resistance for about four feet and then the rear tires lock like it has hit the compression stroke on the engine. This isn't the case because the belt is off, but that's what it acts like. If I rock it a little it will free up again and roll with resistance for another four feet and repeat.  And I still wonder wether the secondary clutch should spin independently of the rear disc. As it is now, if I rev it way up in neutral and hit the brakes hard it takes the rpm out of the engine. I thought I should be able to hold the brake and rev the engine at the same time, I just don't know for sure. Oh, and I made a mistake, it's an '89 not a '90, if that makes a difference. I really don't want to dig into the trans. but it's looking like that may be what I have to do.

I can see why you might think that, but this four wheeler isn't in 4wd unless you put it in.

Hello, I have a 1990 Trail Boss 250 that is in very nice shape. I think it has been very well maintained from all indications. The problem I am having is that the four wheeler seems to take an inordinate amount of throttle to make it go. Once rolling, the second I take my thumb off of the throttle it slows down like it has engine breaking instead of just coasting. The brakes aren't binding, as it rolls easily in Neutral. I have changed belts to see if that would help. The belt also seems to have correct deflection. The transmission has the correct fluid, and is full. When I pulled the clutch cover and found a green spring so I replaced it with the blue/green that is recommended. The primary clutch seems to work correctly. I have not watched the secondary. The other thing that I am curious about is that the input shaft seems to be tied directly to the output shaft even in Neutral. If I put the ATV in neutral and rev it up the rear disc spins, which in itself may not be too unusual, but if I pull the brake lever it decreases the rpm like it is putting a load on the engine. So as it sits, it looks like I have an issue with either the secondary clutch or the transmission. My gut says transmission, but I hope not. I would appreciate any insight as to wether this is a normal condition or, if not, how to fix it. Thanks in advance, Dave

I had a Bayou 300 with the same issue. It would randomly start with the electric start, but always would start with the pull start. Unless you've had similar problems, it's not fun to diagnose.

Glad you found it.

Oh, one other thing, check that there isn't a small vacuum leak in the hose to the fuel pump and that the lines are routed correctly.

I still think it's running out of fuel. The fuel pump runs off of vacuum. If the baffle or spring in the pump is too stiff, it would give the symptoms you describe. I would hook up a gravity feed external fuel source and see if it will stay idling. The other thing that is a possibility is that the engine isn't producing enough vacuum. Try the external tank first, then we can go from there.

Left front caliper not releasing? Jack the front up and see if both tires spin with equal force.

Also, maybe something to do with the left cv axle.

They should be available in the aftermarket. Do a search on eBay or Amazon.

Idle is too high, belt is grabbing or clutch isn't fully disengaging. Those are the easiest things to check.

The only thing I've found is that synthetics will reveal any oil leaks, even those that may not be visible with conventional oil.  I think it is due to the smaller molecular structure.

Probably, but I didn't know just how little would come out.

Just did a top end on a 2000 Xplorer 250. I premixed the first gallon so I could check the oil pump. At idle it fills the tube and drips very very slowly. When I rev it up and hold the lever open the oil runs out very slowly. I checked, and it does make pressure when I hold the lever up, but it doesn't really seem to at idle. Do you guys think my pump is OK? Also, what years used the plastic pump gear? Thanks for your help, Dave