By Emilios garage
Just bought a new Sector 750. It's slightly better looking and equipped than the Axis 700 models they sell at Lowes or the RK and other versions but there's very little difference in the frame and drive train. Seems to be a good machine to use around the farm and riding around the neighborhood. If you own any of these Hisun made machines, you may have similar issues. After driving this around on some country roads doing some break in riding, an extraordinary amount of radiant heat was emitting out from behind the seat and under the dump bed. The engine temp was showing normal on the gauge. The source of the extreme heat was mainly the muffler, and it was even hot enough to soften the plastic underside of the dump bed. You could smell the plastic was almost at that melting temp. I've never seen anything like this on any brand of machine. This could possibly qualify for a safety recall. Back at the shop afterwards to study the situation revealed some suspected bad exhaust designs to be the main cause. The pipe going into the muffler from the engine is 1 3/4 inch in size. The pipe coming out of the muffler is 3/4 inch. A one inch difference! That's a lot of very hot gases going in through a large opening, compressing inside the chambers of that muffler, and trying to get out through a much smaller hole. Simple science will tell you that even cool air when compressed gets hot. Science has also shown that hot air flows faster than cool air. This muffler by design is causing already hot gasses emitted from the engine to be accumulating, compressing and therefore amplifying that temperature to far greater temps than what the engine itself was emitting. I'm sure all that back pressure is also causing the engine to labor some too and wasting HP. The same muffler appears to be used on the 550, 700, or 750 Hisun variants. The exhaust tip on the back of the muffler is removable and when you do there will be even more engineering issues revealed. The 3/4 inch pipe extends inside the rear chamber of the muffler about 3 inches. There is a metal case over and around the internal 3/4 inch pipe section with a steel screen around that. If the 3/4 inch outlet wasn't bad enough, that case and screen cause even more restriction and back pressure compression. Those of us who turn wrenches already know that screen is only in there because of certain mandated requirements, but now we're talking about outflow that would be around the equivalent to a 1/2 inch outlet with all this. The first attempt to reduce the extreme exhaust temps was done by just removing the screen and cage from the internal section of the exhaust tip. The 3/4 inch tip was reinstalled as just the pipe and the machine test driven again. No longer had quite the extreme scorching heat but still felt like the exhaust temp was still too high. I did notice that the radiant heat from the lower exhaust pipe section which is about 4 inches from the drive shaft was enough to melt and burn the rubber boot that covers the shaft yoke just behind the u-joint. Don't know yet if the rubber parts of the u-joint were compromised. The next attempt to mitigate this problem was to manufacture a new exhaust tip with greater outflow. One that would have the same size pipe on the outflow side to relieve this engine of back pressure and fix the heat problem. My car, my riding lawnmower and other brand UTVs have mufflers designed this way, why not this Hisun machine? I could not find any aftermarket companies that already make this part, so now I do. If you are handy with a mig welder, a drill and some hole saws, then you can make this part too for around $20 worth of materials. (Bi-metal hole saws not included) It's up to you what angle you want coming out of the tip. I went with 90 degrees and a slight downward angle, but 45 degrees will work too. The exhaust outlet is now also a 1 3/4 inch pipe. This seems to have fully solved the extreme exhaust heat problem. The engine idles smoother now, and I do not notice any louder exhaust noise than what I had before. In fact, it's actually quieter now because the high-pressure air release noise the original tip made is gone. The issue of the lower pipe heat next to the drive shaft is still being evaluated. Possible fixes for that if still needed would be a shield wrap on that section of the exhaust pipe or a clamp-on aluminum shield. People, this is an engineering issue, no warranty can fix this. Attached are some pictures I took during this project. Good luck with your Hisun machines.
Safe trails, E
Ive searched and cannot find any performance parts that fit my machine.
I have a 2020 coleman ut400.
Im looking for machined sheave kit, programmers, cdi, exhaust and intake.
I know these are yamaha rhino clones but are they rhino 450 clones?
Any info is appreciated.
1 1/2 years ago I was riding along in my 2018 Coleman 550 Outfitter when the CVT belt broken. Just prior to that I was having some shifting issues that I now understand can be part of the clutch. Finally a few months ago I sent it in to a shop who put in a new belt as well as a new wet clutch (drum, one way bearing, etc and an oil change) He fired it up and it turned on fine, sounded fine and I took it home. It was an auto shop but not a UTV specific shop. So get it home and after a half hour or so it started making some noises with my 10 year old driving it around. I get home and he said theres noises again and I played around a bit. Within a short bit of trying to drive it around I started having noises that I now understand was my One Way Bearing being destroyed. Aka metal noises from the bearing falling apart. Of course, after the cost of $800 to take it to a shop plus $200 in gas, trailer rental etc to take it in and back (it was a friends shop that was a bit of ad istance) I was quite ticked and pushed the UTV back into my garage and left it for a while. Then this past weekend i watched a bunch of Youtube videos along with a mechanic friend to pull things apart. We found the spindle was loose, opened it up further and found the one way bearing fell apart in my hand and the little bearings were already worn, no longer round and this was from less than a hour of use. THerefore leading me to believe it had very quick failure after the new wet clutch was put in. We looked things to look for damage further. Nothing really scratched/grooves etc so I ordered a new OEM bearing and we put it in, sealed it back up, followed the specs of everything and was 110% sure we put the One Way Bearing in correctly. We rode it around for a hour, sounded fine. Next day used it, sounded fine for a half hour. Third day I turned it on and let it idle a little bit and found that I was hearing metal scraping again like I did right after getting my utv back from the shop. Therefore I am 99% certain the One Way Bearing is about to break again (already breaking) Its a brand new OEM belt. Nothing looks off on the spindle. I do not know for sure if the shop touched the inner race for which, in my understanding, the One Way Bearing spins. I know I may be sounding ignorant here. I am not a mechanic by any means but I have learned a bit with the recent Youtube videos and attempted repairs. Whatever that "ufo" looking object is, we replaced the bearings (those black things that spin) I replaced the whole "Ufo" lol... as the original had some wear/tear that prevented it from spinning perfect. Nothing currently
visibly looks off... and the issue is mostly when the machine is more in an idle. It was at an idle when the One Way Bearing sorta went kaput the last time. THe noises is at an idle... but if I can get it drive, its fine. It also affects the ability to shift the gears.
I know I will have to replace the One Way Bearing again... I just dont know what might cause the issue that is destroying the bearinga nd so quickly. Again, this all started when the belt snapped when I was going about 15 mph down a road on a warm day. It has higher miles. The wet clutch was in bad shape and its replaced. The paperwork says "wet clutch assembly kit") Is there something that the belt can do to cause damage that might not be as visible but would directly create an issue that lets the bearing get ate right up?? Help me! I hate this machine and I really want it to run well ... so I can sell it and find something else haha..
While installing the High lifter lift kit in my 2015 Mule 4010 I nicked the piston, strut rod, the shiney rod in the middle that I cant remember the name (no coffee yet this morning). I knew the nick was deep enough to eventually tear up the seal and she'd let loose. Well 3 months or so down the road here we are, its blown out.
My question is how do I know which strut I have? I see 2 listed in the exploded 45023-1006 and the 45023-7503. The difference is the spring rate or K value. Seeing as I have high lifter springs does it matter the K value? And if that's the case can I use any of the 45023 prefix struts from various other models?