Joe Toup

J. Fulciniti - After doing some digging on the engine, I believe you are correct. Found some info using the engine family from the identiplate under the seat on the frame rail (Shows displacement, spark plug gap, timing, etc). Turns out there is a company called Taizhou Nebula Power Co., Ltd., located in Taizhou City, Jiangsu Province, China. They make a series of UTVs that is nearly identical (minus badging) to the Massimo, Bennche, Linhia, and Cazador. They have a model # XY450U-A. The engine model family (KMMMX.391XYB) can be seen on the attached spreadsheet line #884. The irony is, the engine is nearly identical to a Hisun the best I can tell. I have not been able to find anything yet that convinces me it is made any differently. They may have sold the series to Taizhou. Not sure since Hisun is still in production. In theory, they should operate the same and be repaired and maintained similarly as a Hisun. The website for Taizhou Nebula Power Co is here: http://www.tznebula.com/eng/ Some of their links, while not specifically named "Massimo", do provide some great info that should be beneficial as we build a repository of owner background info on these Massiomo/Bennche/Cazador/Linhai 400's. Stinks we have to do this kind of searching to overcome the shortfalls of the company. But it is what it is. off-road-mc-atv-utv-recveh-2006-present.xlsx

I wouldn't necessarily say that. I go up and down some steep hills in high and low. Have never had the CEL. But that doesn't mean I won't. Your problem is one that may affect many of us. Will be interesting to see what the real cause it. Many of us curious. This kind of stuff is in my veins!

Did you drive down the hill in low at all?

The Fumoto would probably make it much easier to drain the oil before pulling the screen to check for particulates. Changing oil makes a mess unless you have a funnel right up next to the plug. Great concept. My preference would still be to remove the screen after draining.

No need to give me credit. It’s educational info only. I make no money from it. Just sharing what others have put out there in other forums, technical pages, and some guides and handbooks. I added some of my own experience to it and reworded a lot of it so it made more sense to me instead of fragments from all over the place. This legal reference covers what is posted to our forum when it is being used as educational, teaching, or research material...and not for profit. "17 U.S. Code § 107.Limitations on exclusive rights: Fair us", retrieved from https://www.law.cornell.edu/uscode/text/17/107 Therefore, it is my opinion that there would be no issues with printing a copy for personal use.

Using info that is out there for public knowledge and use is not an infringement on copyrights as far as I am aware. Especially if it is for educational purposes and not for profit. You should be okay to print it. I copied it from multiple sources and combined the stuff into a sequence that made the most sense to my binary mind.

The engine does have an output shaft. The belt is internal (you can’t see it) and drives the clutch. sounds like you may be close to figuring out the CEL. The oil pickup tube seems extremely logical. Keep at it and let us know what you find out.

No doubt the manual stinks. There is no filter on this engine. The manual is misleading. It was probably written for the 500 model that has an oil filter. The engines in the 400’s don’t use a filter which equates to no real filtration. They should have updated the manual as such with better intervals IMO. The HISUN engine is a finicky little beast. Like most single cylinder engines, it breaks in fast. While doing so, there is a significant amount of microscopic gunk that gets caught in the oil. No filter other than a screen means it gets recirculated thru the engine and has the potential to carry harmful particulates inside places it should not remain. My first oil change at 25 miles...I found all kinds of little bits in the oil. The second change not so much, but some nonetheless. Had I not changed it for 250+ miles, no telling how many of those little foreign bits and flakes of metal would have recirculated through the engine causing damage. The solution is, we need to exercise a little more due diligence during break-in periods. Oil changes need to be done more frequently. Extremely doubtful you did any damage to your engine. Just get the oil freshened up before anything else. Change it often. It’s your machine’s underwear. Don’t let it get funky! - JT

J. Fulciniti - Great clues. Change your oil before you do anything else. And start driving in low gear when you take those hills. Up and down. Not only will it extend your belt life, it will help you see if the issue is specifically tied to high gear only. If it is and does not happen in low, your belt is most likely stretched. These CVT clutches will wear a belt out fast if you only run in high gear. No joke. And if you haul a bunch of gear and/or people (do you have the dump bed or the golf cart rear seat) the extra weight will play a significant factor. If you have the golf cart rear seat, and you have been hauling 4 people....you may have stretched the belt running only in high. It happens. But...we are still troubleshooting. I am interested in knowing what happens when you roll down hill in neutral...and in low gear too. Give it slight throttle going down hill. You won't hurt it more than already have if the belt is the issue. If you are running 5, 10, 15 mph consistently, you should always be in low gear. High gear on a CVT is meant for 25mph and/or flat land, no mud, and no loads. 268 miles...you should have changed the oil three times by now. 25 miles, 100 miles, 250 miles. Then every 500 and your machine will last forever. 1 - I only drive in high, all we do is cruise around our community roads at varying speeds. 2 are rather steep 2 - I have not as I did not want to build too much speed 3 - 268 miles no heavy loads 4 - no backfire - I'll try neutral today if I can. Ran around the lake last night 3.8 miles on basically flat roads - just 2 small hills. (I can easily avoid the steeps) with flawless performance.

You can get this oil at Walmart for around $3 a quart. Meets spec for the Hisun engines in the Massimo/Cazador/Benche 400. And it won't break the bank. It's in the motorcycle section. Don't overthink oil. The key to oil is buying one that meets spec, changing it frequently, and checking the screen for particles, loose metal, shavings, etc. These are indicators of wear or something about to fail. Oil will often tell you if you have an internal problem just like knocks and pings. If you feel more peace of mind by spending extra $ on full synthetic, rock on. I do not. I buy conventional and change it frequently. The detergents in conventional help these engines. They are designed to run with conventional. But you will always find folks that swear by synthetics. I can rebuild an engine that has synthetic and one that has run conventional its whole life with regular changes...and there is seriously no difference. The only time there is a difference is when people do not change it when needed. Like when they skip the break-in oil change interval and put 268 miles on a new machine. 🙂

Hey guys - Sorry for chiming in so late. Haven't been on here in a while. There is a LOT going on in this thread. I'll see if I can help some. Couple things I noticed. 1) @strike250 did not reply to my request for a manual, so I ended up buying one. He may be like me and got too busy check this site frequently. Regardless, the manual was not worth the $75 I spent. It does little to give you useful info to troubleshoot much. It is a paperweight. The HISUN manual for their engine is much better. That is where I get most of my info for troubleshooting these machines. I can send you a digital copy if you send me a private message. 2) The low oil pressure connection may not be worth chasing. It is a logical thing to consider, but I seriously doubt it will result in the fix since you have good oil and you are not having a light at any other time. I think you have something else going on. 3) The oil for the wet clutch is a possible candidate...but I am still not convinced the 400 machines have a wet clutch. I have not been able to confirm it is a true wet clutch. If it is, and your oil is over due a change, that very well could be a contributing factor. Think of the wet clutch oil as a friction modifier that is similar to what is used in a hypoid rear end differential for a limited slip set of gears. If the friction modifier breaks down over time, you loose the friction capability of the oil. Changing it does help. At 1.25 quarts, changing the oil in these machines is the easiest and cheapest thing you can do first to rule it out as a suspect. But more likely, you may have a belt issue. When a vehicle, ATV, UTV, etc, is going down hill, the engine is not carrying the same output load that is required to drive it. It is basically "floating", for lack of a better way to explain it. The wheels spin (assuming no throttle applied) thus causing the engine to be turned slightly. Meaning, the engine is not pushing the machine...the wheels are pushing the engine through friction in the driveline. Make sense so far? The reason the CEL might be coming on could be a few different things. If the U-joint has play in it, or if the belt is too tight or too loose, the engine speed may have a slight variance on the output driveline. The crank position sensor would potentially see this slop and send a false signal to the ECU that might believe the engine is experiencing a miss fire. You could check the fault codes on the dash for a misfire (code 0351) by following the process I posted in an earlier thread for fault codes. If you have a fault code, you can clear it using the process in the same thread. However, I would need more information to continue troubleshooting. 1) Are you in high gear or low gear when this happens? Does it happen in both gears or only one? Knowing this would help isolate it to more of a belt issue. 2) Have you tried applying throttle when going down hill instead of coasting to see if the light comes on? If so, did it make a difference? 3) How many miles are on the machine? The belt might be worn already if you are riding it to climb hills in high gear only...with heavy loads and/or towing. If it is loose, you may have all kinds of slop in the driveline that is causing strange things to happen when going down hill. Just a hunch. 4) Does it backfire when going down hill? Try putting it in neutral and see if the light comes on while going down hill. If you have a problem with the angle of your engine and suspect oil starvation, it would most likely still do it in neutral. I doubt it will in neutral. 5) My last and probably most favorite suspect for weird things that happen when engines have back pressure issues....valves! if they lashed them incorrectly you may be having a higher than normal amount of pressure when going downhill due to the driveline load. Think in terms of jake braking. As for the fault code reader and reading live outputs, that is tricky. There are some methods out there that allow you to observe functions with your laptop. Most are new and still being payed with. The one I did find seems to be promising but the USB to 6-pin connector under the seat is the hard thing to find. I will see if I can locate a source and the software needed. The reader I built works but only to see and clear codes. Does little else. You can do the same thing with the key sequence on-off-on-off-on (3 times - leave on) to get codes....then on-off-on-off-on-off-on-off-on-off (5 times - fast - turn off) to reboot the ECU. Hit me back with the extra info and I will see if I can help you peel the onion back a little further. - JT

Hey Folks There are not a lot of good sources out there for troubleshooting and diagnosing ECU problems with the Massimo Buck, Bennche Bighorn, Bennche Cowboy, & Cazador machines that use the Delphi MT05 ECU. They are all basically the same with different badging, so I thought I'd share some info that I found during some searches. I was trying to help someone diagnose and repair a hard starting issue. The ignition coil was throwing a 0351 code. I discovered how to read codes without an OBDII code reader. The following procedures should help you check your fault codes and clear them if needed. Fault Code Troubleshooting for Delphi MT05 ECU on the Massimo Buck 400, Bennche Bighorn 400, Bennche Cowboy 400, and Cazador 400 *NOTE: The MT05 ECU is not really OBD 2 compliant. It is much more similar to an OBDI system. The MT05 ECU controls either 1 or 2 cylinder engines commonly found on Massimo, Bennche, and Cazador. Much of the ECU info was found here: https://netcult.ch/elmue/HUD ECU Hacker/Delphi MT05 Manual.pdf Delphi EFI System Design Delphi EFI employs 5 sensors to monitor engine performance. 1. Crankshaft Position Sensor 2. Coolant Temperature Sensor 3. Oxygen Sensor 4. Throttle Position Sensor 5. Manifold Air Pressure/Manifold Air Temperature (MAP/MAT) Sensor Delphi EFI employs the following system components. 1. MT05 Engine Control Unit (ECU) 2. Fuel Pump 3. Multec 3.5 Fuel Injector 4. Idle Speed Control Valve (Idle Stepper Motor) 5. Multec Ignition Coil 6. Fuel Vapor Canister Purge Valve Using the Digital Dashboard to Decipher EFI Trouble Codes In addition to commercially available diagnostic scan tools (Big $$$), you can use the engine warning light of the Siemens dashboard to diagnose most of your EFI problems. The digital dashboard receives signals from the MT05 ECU, and the engine warning light will flash a diagnostic trouble code (DTC) if the ignition key is switched on/off for three cycles. When you turn on the ignition, the engine warning light will illuminate, which indicates the EFI system is operational. After the engine is started, the engine warning light will extinguish if the EFI system is working properly. However, if the engine warning light remains illuminated, it indicates the EFI system is not working properly, and there is a system component failure. Deciphering Diagnostic Trouble Codes To read the diagnostic trouble code (DTC), open and close the ignition key three times in rapid succession, as follows: open/close—open/close—open. At this point the engine warning light will flash a DTC which indicates the fault in the EFI system. Refer to the attached fault code table to identify the corresponding problem. The engine warning light will emit a sequence of flashing lights. If the light flashes 10 times, the translated number is 0. If the light flashes one time, the translated number is 1, et cetera. For example, if the MAP/MAT sensor is disconnected, or the connector is shorted to ground, the engine warning light will flash in the following manner (This is an example only). The engine warning light will flash 10 times: The first number of the DTC is 0 After an interval of 1.2 seconds, the engine warning light will flash 1 time: The second number of the DTC is 1 After an interval of 1.2 seconds, the engine warning light will flash 10 times: The third number of the DTC is 0 After an interval of 1.2 seconds, the engine warning light will flash 7 times: The fourth number of the DTC is 7 The resulting DTC is P0107. NOTE: For the system I was helping to troubleshoot, I suspected an ignition coil failure due to the code that was thrown. When it was checked, it was flashing: 10, 3, 5, 1. The 10 represents a 0. So the actual code was 0351. After finding the code, the coil wire was checked and discovered loose at the spark plug. Once it was pushed fully on, the problem was fixed. Most likely, this problem was created after the owner had pulled the spark plug to check the gap. The ECU was rebooted using the procedures detailed below with no more codes being thrown. If there are other fault codes, the engine warning light will flash the next code in 3.2 seconds after finishing the first sequence. After all existing fault codes are flashed, the engine warning light will repeat the fault codes in a loop sequence, until the ignition key is turned off. To clear fault codes you either need an OBDII Fault Code reader and a Delphi 6 pin connector adapter cable that you have to order from China and wait 8 weeks…OR....you can simply reboot the ECU using the instructions detailed below. Rebooting the ECU Perform the following steps to reboot the ECU. 1. Turn off the ignition for 15 seconds. 2. Turn the ignition on/off for 5 cycles. Make sure each cycle lasts about ½ second, verifying the start of the fuel pump for each cycle. If the fuel pump doesn't start during any cycle, begin the entire reboot procedure from the beginning. 3. Turn off the ignition for 15 seconds. TPS (throttle position sensor) re-learn procedure after rebooting ECU. This should be done after replacing the TPS or the ECU....and it is advisable to check proper idle after rebooting an ECU too. Source: ECU Hacker (Reworded process slightly to make it a more sensible flow in my mind): 1. Turn the idle screw one full turn clockwise before starting 2. Start the engine, and run at low idle until the engine warms. Maybe a couple of mins. 3. Idle should be above 1500 rpm. If it isn’t, turn it up to 1700 then shut the engine off. Do another reboot of ECU. 4. Restart the engine and let it stabilize at 1700 rpm. Then turn the idle screen down to 1500 rpm and let it stabilize for a few seconds. Once it stabilizes, set to the final recommended idle speed for your machine. The placard under (or behind) your seat should show idle speed, valve adjustment, spark gap, etc. Typically the 390 cc engines in the "400" machines run at 1600 rpm idle. 5. Shut it down. Wait 10-15 seconds before restarting. The procedure is now complete. Final Notes: I have included pictures of an OBDII connector and the Delphi 6 pin connector in case anyone wants to go buy stuff off ebay or local parts suppliers and build a connector to use for an OBDII reader. But...you can save money and simply do the same thing with code reading and resetting using the check engine light on your dash. Some folks prefer to do it with code readers. Hope the information provided helps if anyone ever needs it but cannot find it in repair manuals. I discovered most of this in some motorcycle forums. The source for the diagrams is here: https://netcult.ch/elmue/HUD ECU Hacker/ Be advised: I am not a service technician. I do not endorse any manufacturers. I do not get paid to help, nor do I want to. This is just a hobby of mine. I enjoy working on things and solving problems. If you run into a weird problem that stumps you, give me a shout. I may be able to give you some ideas...or not. Just know, that troubleshooting thru emails can be challenging. The more info you can provide, the better. Otherwise, I will probably ask you a ton of questions. The good news is, the Delphi system used on these machines is essentially an OBDI and it is very simplistic. If you are methodical and patient, most of your "problems" can be figured out thru a process of elimination. Always go for the simple things first before throwing money and sensors at a machine. Take care - JT