2017 Massimo MSU500 Thermostat Malfunction

[NewCadetOwner]

What did you order?  I have received things pretty fast from the dealer out west

[Joe Breaux]

the shop ordered a complete  new  Cylinder Head assembly .. Was promised to be there last Tuesday.. still waiting .. At this rate, it may never see 400 miles 

[Travis]

Seems pretty pathetic on mAssimo's end...

[Joe Breaux]

lol  that's an UNDERSTATEMENT.. everything about mAssimo  is pathetic.. I wish someone had told me before I spent $8K on one.. the worst company I have ever seen ..

[Joe Breaux]

still waiting on parts …. talked to 2 other shops, both now refuse to even work on Massimo products because parts take so long and if its warrenty, 4 months to get paid is ridiculous .. they wont touch one anymore .. its just sad … Talked to an ATV /UTV engine  Rebuider , he says he thinks one of his rebuilt  Rhino engine would work on it , if not, he would let me return it.. So if this pattern continues,  RHINO here I come 

[NewCadetOwner]

Did you try Motorcycle Doctor in MO?  They have been awesome and have parts in stock.  I have had great luck with them.

[Joe Breaux]

no, the shop doing the work ordered it.. I just called him, he says he got shipping confirmation finally... be here in 3 days... maybe .. any luck resolving your overheating problem yet?

[NewCadetOwner]

Not yet.  Just got off phone with the shop trying to get it in.   Im pretty sure it is same issue as you either a gasket or head.   Thing runs fine with no signs of a problem other than antifreeze disappearing and then overheat.  Sadly I love the machine just not the headaches.

[Joe Breaux]

well, when we get both fixed, maybe can go riding together .. for about 30 minutes till they break again ..lol  ….Its really sad, it runs great for 20 -30 minutes.. then overheats and will not cool down  .. also we   have bypassed the temp switch on radiator to make fan run continuously now when key is on .... maybe that will help some by keeping the temps down all the time .. You might consider it too 

[Joe Breaux]

we[l, shop called, parts came in, installed running good, but now waterpump took a crap.. so here we go again 

[NewCadetOwner]

Thats more than odd!  Did waterpump not work before causing the overheat and cracked head?  Was the waterpump leaking for them to say it is bad?

[Joe Breaux]

Waterpump appeared to work before but was weak after new head install.. Did it cause the head problem? who knows?  EVERYTHING is  replaced now.. Got it back this morning.. drove it for about 40 minutes around my yard, but that's only 2 acres.. did not run hot.  RAN PERFECTLY!  has more zip , maybe it was losing compression. .. NOW, with the fan running 100% , the engine seems much cooler and way less heat from behind seats ..  . Tomorrow I ll go to my camp at Whiskey Bay on Sherburne Refuge.. I ll put it to the test there, got about 15 miles of trails to ride for UTV ,ATVs …. HOPEFULLY  I can get another 300 miles out of it …   Any progress on yours?  I would check pump and bypass fan switch.. Good Luck

[Joe Breaux]

well, theres no joy in MUDDVILLE tonight..it took about 5 miles on the trail , and BAMM .. we are back to square one... I am just disgusted with this pile of crap 

[NewCadetOwner]

What did it do this time?

[Joe Breaux]

same thing it always does everytime I use it... same thing Massimo is world famous for....IT OVERHEATS … Dropped it off this morning.. I ll let you know what they find 

[Joe Breaux]

Well, I got it back.. Its running fine, but it always ran fine ..TIL IT OVERHEATS ................. so far , one day and its still working... Maybe I can get more than 10 miles this time before it breaks again ... 

[Joe Breaux]

Well fellows, there JOY IN MUDDVILLE TONIGHT.. I ran it all day saturday and half of today.. it was 95* outside.. It ran perfectly, and NEVER OVERHEATED!!!  Finally after months of frustration, and trips to the shop, it is working properly  .. We do have the fan switch on radiator bypassed to run continuously when key is on.. Theres far less heat coming up behind the seats now.. It did develope a small exhaust leak, but I dont even care ..  cheers 

[NewCadetOwner]

Awesome news!  What did they find this last time around.  Mine is in shop now with head coming off next.

[NewCadetOwner]

Well got report back on my 750.  Blown head gasket and warped head.  The mechanic found the head bolts were not torqued correctly and thinks it caused the head to warp and gasket failure.  

[Joe Breaux]

thats exactly what I had.. I suggest you replace the waterpump and bypass the temp switch for fan to run 100% or you will be back there again 

[NewCadetOwner]

Yeah based on your experience I ordered the waterpump with the head.  What was the problem that yours had to go back after they replaced the waterpump?

[Joe Breaux]

defective chinese gasket .. ask if they can use Yamaha .. shop warranteed it tho.. no cost .. Its running really well now.. but who knows how long  

[NewCadetOwner]

Great.  I have the gasket kit already.  I will see about getting the yamaha one.  Thanks for the tip.

[Joe Breaux]

Good Luck... btw, took mine out yesterday again to the trails at the River... ran absolutely perfectly .. never got hot at all with fan running 100% now.. and I dont have all that hot engine air coming up behind the seats now..  And it was brutally hot outside. in the swamp .... 96* with a 110* heat index.. ran at least 25 miles... My mechanic did a good job.. hopefully this will end my problems from a couple years ... NO THANKS TO THE "EXCELLANT" SERVICE DEPT AT MASSIMO RIPOFF MOTORS .... ps  I removed the winshield  completely ,,, MUCH BETTER FOR DRIVER 

Edited August 16, 2020 by Joe Breaux
dropped my beer

[NewCadetOwner]

Grewt to hear!  I just dropped new head and water pump off at the mechanic.  He is swamped but hoping to get it back in a week.  He is going to get a Yamaha gasket and see if it will work in lieu of the Hisun.   Fingers crossed.  Did they figure what caused yours to go bad in the beginning?

[Joe Breaux]

Well, another weekend of fun in the sun.. right after Hurricane Laura theres lots of mud! and the damn thing did not run hot!!!  WOO HOOO  finally working properly and so far appears RELIABLY!  And once more I would like to give a great big  middle finger salute to the ahos at Massimo Motors Service Dept who refused to help me in any way... 

[NewCadetOwner]

Well wish me luck.  After a new head, waterpump, intake manifold cover and Yamaha head gasket I pick the beast up tomorrow.  Told it runs great and should be ready to go.  Have my fingers crossed!

[Joe Breaux]

With the Yamaha gasket, I ll bet you wont have any more issues if yu run the fan 100%

[NewCadetOwner]

Fingers crossed!  Mechanic says its running great so only time will tell.  I think I will add a heat gauge so I can watch it and not have to wait on a light.

[Joe Breaux]

I thought about that too, but its running so much cooler now I m not worried.. Even the heat that used to come up behind the seat is gone ,... Good Luck, and enjoy if it works.. They are a lot of fun when they run right