kgs

I had the same problem, it was my valves that got to tight. Adjusted both valves to 3 thousands and now starts right up and idols good.

I would think it should go a little faster but not much, I got a hisun 550 sector which has a different motor then the 500 but I can get it up to 45 before the limiter kicks in and has it cut out, that's so you don't blow your motor up.

While you got it apart, I would check the rear differential to make sure there isn't a spring behind that nut.

Yes I agree, those splines inside it are probably got some rust on them.

Yes that's normal, unless you want to blow the oil out of the oil cooler,then it would be 3 quarts. I personally don't do it, I add just 2 quarts.

I run high range most of the time, only use low range if I have to go up hills off road below 20 MPH.

Yes I keep mine greased on a regular basis, especially the drive shafts, I use mine to carry corn to feed deer and most of driving is on gravel road, just changed tires on it so should get another three years on them, mine is a 2019 and just add to adjust valves because they didn't have any lash or play in them. Now it starts and idols like new.

I got over 500 hours on mine and change oil probably about every 500 miles, when I change oil it isn't real dark so probably change it before it's really needed, but this time it cost me $34.00 for two quarts of oil. Used to get it for about 6 dollar's a quart.

I got the hisun sector 550 with out the oil tube extension, when I change oil I don't empty the lines on oil cooler. I got about 6000 miles on mine and add two quarts of oil when I change it and it is a little above the full line. Over filling can cause damage on motor, causing seal's to blow from pressure I would think. Here's the oil I use and has worked well for my hisun.

Your welcome, glad you got it figured out.

Number 8 9and 47 is all that goes in there.

Yes, but the splines inside that housing is probably stripped, the spring behind that nut doesn't belong in there, throw it away. Here's a diagram

Your welcome, if you look what you got sticking out, it's about a perfect match to mine gear you see what was sticking out. Should still be under warranty, hisun will give you the parts for free if you take it back where you bought it. But could take months before you get it back. Those two pieces isn't that expensive. But hisun knows some utvs went out that way. I bought mine in 2019 I would of thought that problem wouldn't happen on new models. I got 5900 miles on my now and it's running good, just had to adjust valves last week because they got tight.

That gear shouldn't be sticking out, when you put Greece in your driveshaft it will expand, but I got a hisun sector 550 that was put together wrong from factory. Mine had a spring behind the nut in the differential, only way to know is remove driveshaft and look at that gear, and make sure they didn't add a spring behind your nut, it will keep that gear from going all the way in. That's probably about the same amount of miles on mine before it happened to me, here's picture of bad parts, don't put the spring behind the nut if yours has one behind it.

Sounds good because I know what you mean, my 550 sector is the same way. Can't have a conversation while driving it with wife.

Yes I agree it could be that, easy thing to do before you tear things apart is put it in 2WD and have your buddy look at the universal joint while giving it a little gas to make it move. If the universal joint turns and the driveshaft doesn't then one of the splines is stripped out.if the universal joint don't move at all then the problem is spline going into universal joint on back of motor. If that's not stripped then it's in side like stated above. I hope it's just a stripped spline on your drive shaft.

Yes that other spline goes into the universal joint on one end, the other end of the universal joint is attached to the back of the motor. That's where the worse case could be. So if you put it in 2 WD and the universal joint on the back of the motor doesn't move then it's internal problem's. But I agree take the universal joint apart so you can inspect the main shaft on rear then look at the one on back of motor.

Being in 2 WD and you say it wont move isn't good, because if it was the gear I'm talking about the rear driveshaft would still turn but utv would just set there making a noise. So it could be a gear inside the motor that put the power to the rear driveshaft, which sounds like a big job. With that motor mount bolt being out could of put the motor on a angle which caused something to go out in the rear driver train. I hope I'm wrong but need to look it over and see if the another motor mount is missing. Let us know what you find out when you're neighbor looks at it.

Yes you need to put a bolt back in that hole, you see that black rubber Peace on the rear end. You can fold that down to see if that gear is messed up or not, that rubber Peace keeps dust out of there. It fits pretty tight. But it's probably ok if you can turn wheels and don't hear anything.While you are at it try and jack up the front and turn the wheels. That bolt needs to be put back in, motor under power with that bolt out could cause your motor to move around under load which is not good.

Yes it made loud clunky noise with the gear catching and slipping unit I got it home. If you look at the back drive shaft you should not be able to see that gear, if you can see that gear sticking out some you could have the problem I had. Your friend will be able to tell real quick by looking at mine and looking at yours with out tearing it apart.

Here's my parts removed, the spring was not supposed to be behind the nut. In the rear driveshaft connecting seat.

Yes check the rear driveshaft and see if the gear is inside the rear driveshaft connecting seat. My hisun was put together wrong from factory, someone somehow put a spring number 45 behind the nut number 8 which I don't know how they did it because it's so tight in there with just the nut. But it causes the number 6 drive shaft sleeve to only be in the connecting seat about 1/2 a inch. Hisun did give me the parts free to fix it but I'm sure there could be a few out there that was assembled this way. Here's picture of there diagram that shows the numbers I'm talking about. Hopefully this is your problem it's an easy fix with the new parts, just don't put the spring behind the nut when putting it back together, hope this helps. I got my old parts to show if op want to see it.

Yes I hope I do, I only use it to haul corn to feed deer, so it don't get abused driving it hard in woods. I've been told the motor in the sector 550 is the same motor in the sector 750 and supposed to be a good motor in the hisun utvs.

So if you have a hisun sector 550 it's a 4 stroke, which means the piston goes up twice before you get the compression stroke. Set piston TDC on compression stroke then adjust both valves to 5 thousands clearance. My utv runs like the day I bought it from this fix.

Well adjusted the valves to 5 thousands, now it runs like when I first bought it. Turn the key fires right up and idols on it's own, very happy man. Thanks for all the help.