Joe Breaux

Hopefully the previous owner got all the problems worked out before you bought it.. .. enjoy it ..When mine actually runs, its fun to drive.. problem has been ,its in 20 minute increments, then back to the shop.. now I m waiting on a new Cylinder head to replace the cracked one mine has ..

take your pick...factory defect, poor quality material, multiple episodes of overheating [ altho I never ran it after hot light came on] .. inadequate cooling system to begin with. Engine runs way too hot from factory settings.. ALL OF THE ABOVE? .. and now we know why Massimo dumped HISUN motors.. I wish I could find a reasonably priced, quality rebuilt or new old stock Yamaha Rhino engine to replace it..

update.. more misery from this disaster called Massimo with only 300 miles on it..... Not head gasket.. CRACKED HEAD .. more money down this bottomless pit .. waiting for new head now

mine as well as several others I have talked to , are plagued with constant overheating issues, resulting in blown headgaskets… and clutch/trans issues .. Massimo admitted to me in email that these 500 and 700 HISUN engines were not good and they discontinued them, went to another Chinese Company for engines .. But refuse to help any of us that were dumb enough to buy them.. I bought mine in 2018 new.. its been in shop 5 times , only has 300 miles.. I hope you have better luck. ….oh, and its in the shop right now.... HEAD GASKET

Welcome to the site.. I truly hope you do not have the never-ending problems that so many are having with these Massimo machines..

So, I talked to the shop owner today, he says it will be ready next week. Should be Ok , no water got in the oil .. FOR NOW at least. He also recommended bypassing Temp switch on radiator for cooling fan.. he said it comes on at 210* and goes off at 190* which means the engine is near 220* all the time.. The fan will now run when engine is on, keeping the temps down 20-40 degrees lower. Maybe head gaskets will survive longer? Who knows....It sure has been a disappointment owning this thing... anyone know if a YAMAHA Rhino motor will interchange with the Hisun junk motor? Or where I could buy a new or remanufactured Rhino Engine? Its supposed to be a copy of a Rhino

I did threaten legal action since it broke the first time on its very first day.. They laughed and said I wouldn't be the first! .. apparently they don't really care about their customers or their reputation. All I want is for it to work properly but it seems the HISUN motors 500 and 750 are incapable of that... Anyone know if a Yamaha engine will work on these ? I m told Hisun copied the Rhino motor.. will it bolt up? and where would I get one?

thanks for the reply... I am just disgusted by the whole mess.. BTW this is the response I recently got from MASSIMO MOTOR SPORTS home office... The business stated:

I put a negative complaint on Dallas BBB . heres . Massimos response ……….."Mr. B&*(* , You are correct we did end our contract with HiSUN because of engine problems. We ended that relationship in 2018 and have not looked back sense. I am sorry if you have had an issue with our customer service department in the past...… " ..................................................................yet they will do absolutely nothing to help those of us that got shafted with Hisun motors

haven't gotten it back yet.. hopefully I can get another 300 miles before it breaks again.. I called local Honda dealer about trade in.. nope … I ll let you know how it goes next week.. waiting on parts to come in .. new gasket, new bolts

after the experiences I have had with Massimo I would STEER CLEAR of anything they sell.. and forget any warrenty..its non-existent .. and Tractor Supply will laugh in your face

UPDATE.. brought it to a shop.. Head gasket is leaking causing air in coolant, vapor locking system.. Shop says headbolts were not even torqued .. poor quality gasket.. MASSIMO refuses to even talk to me even tho it has overheated repeatedly since the very first mile I drove it and I called then that day. .. has been in 4 shops, ALL AT MY EXPENSE!!! Massimo has refused to do anything since day one.. It had only a cup of coolant in it from Tractor Supply when NEW .. Tractor Supply said ...NOT OUR PROBLEM... it currently has 300 miles on it.. has overheated since day one.. Massimo would never repair it. WARNING..DONT BUY MASSIMO .. EVER

STAY AWAY FROM ANYTHING FROM MASSIMO ..trust me on this , or you will regret it

well, after a dozen phone calls and emails to customer service at Massimo Motor Sports, someone finally called me back.. First he claims he never go my emails and messages , then said well its out of warranty, even tho its been overheating since the day I bought it new at Tractor Supply, and Tractor supply and Massimo have record of it, I was just out of luck.. They wont even give advice.. Great company eh? When I pressed him about all the 500 and 750 MSU s overheating, he admitted the Hisun motors are junk and they stopped using them 2 years ago.. his phone call was recorded ... So any of you with MSU 500 or 750s, be aware Massimo could care less how much they break down, THEY GOT YOUR MONEY.. so its now going to repair shop for its 5th time in just 300 miles on it

I took it to the local Massimo authorized shop, he kept it 3 days . Said it was just air lock.. brought it home, first 2 hours or so was fine.. then light came on and radiator was ice cold again.. This thing only has less than 400 miles on it . it runs perfectly otherwise... I guess it must be the gasket allowing gas into cooling system, but it shows no evidence of leak in the exhaust or oil.. it must be a very tiny leak. I will bring it back to him tomorrow .. I found out, Hes the only one in the area that will work on them... I wish I had bought the Honda instead. We have 4 Honda machines. thousands of miles on them, never any issues on any of them..

well so far no joy on overheating.. got water circulating at idle for an hour and a half .. radiator warm, no hot light.. run it down the trail half throttle, 10-15 minutes , HOT LIGHT ON... radiator cold again.. someone please tell me what the hell is going on... no water in oil, no misfire on start, no white smoke at start or running down the road.. driving me nutz

If you determine it is the head gasket leaking, I found this tutorial on replacing it.. seems fairly simple ..https://www.vectorutv.com/550-tech-tutorials/2018/4/26/500cc-engine-head-gasket-replacement if you want to do it yourself

sorry to hear that. ...Is water circulating? Any misfire or white smoke on start up? That's a dead giveaway, air bubbles in radiator while idling ? / check oil for signs of water dilution

I bought mine new in 2017.. it has always run perfectly.. It goes thru anything in 4 WD Lock... You are right the T-Stat is on the bottom of engine .. a real pita to get at .. Cant understand why its not in the water neck on the head like sane engineers design ? Thanks for the info.. I ll run it on the trails next weekend.. I hope its cured..

thanks a lot .. I will do that after T-Stat is done.. how does air enter a closed system, I wonder .. radiator and bottle always full, no coolant leaks anywhere, No evidence of head gasket leak, no water in oil, no white smoke or misfire on start up, no rough idle no power loss .. The machine runs perfectly all the time.. just no water circulating. This is the first issue its had in 3 years

found no air in system.. water is not circulating.. will remove thermostat today.

Massimo Tech finally called me back just now .. There IS a Thermostat. underneath the engine..... I asked about air pocket being the cause , they advised to jack up machine in front , remove caps on Radiator and recovery bottle and run it . watch for burping . I ll try that first ..

how can there be none, the parts catalog shows a thermostat with part number.....just no location .. I have tried calling Massimo but they never call me back

Got a 2017 Massimo MSU500 UTV with thermostat malfunction.. hot light comes on in 4-5 minutes but radiator is ice cold... where exactly is it? The hose neck on the head has nothing in it. I was told it was down by oil drain plug.. only thing I see is water pump.. Is in inside pump housing? Cant find any exploded diagrams that show it.. how to I remove it? any help would be appreciated