Kawasaki Mule

strike250, Thanks for the info.  I'll look into having the head ported, a performance cam and exhaust.  

I just got off the phone with Hisun. So, the MSU 700 is a mix of parts from the Yamaha parts bin. They are using a Rhino 660 cylinder head and it has 5 valves instead of the Yamahas 4 valve head on the Rhino 700. They had to use a mix of yamaha parts to keep Yamaha happy. This way they can say they didnt copy their engine. There is no real way to know if the kit will work.  If you are looking for additional power, I would perhaps get a Rhino 660 performance cam, port your head and have a good exhaust system. The fastest way to power is how fast you can get the air and fuel through the engine, per the cylinder head. This will do more for you than any big bore kit. Porting alone will increase your power. Porting can be done by almost anyone who you trust in your area. The cams are available online almost everywhere as well. This is just my 2cents.  Another way is to program your ECU for additional fuel curve. They have their own bore size. engine size: 686cc bore and stroke:102×84.0mm compression ratio: 9.2:1

Is it ok to post a link to the kit on here? Also, just from looking at pictures the MSU 700 head appears to be the Rhino 660 head, it has 5 valves, where the Rhino 700 head has 4 valves.  Again, that's just looking at pictures, I haven't torn mine down.

In order to keep Yamaha happy, Hisun had to change the design by 5%. The clutch can use a Yamaha replacement or any aftermarket clutch that will fit the rhino 700 as well. As for the cylinder head and cylinder it is slightly different. Not sure if the aftermarket kit will work. what does the kit come with? Is it just a larger piston and you bore out your cylinder? or does it come with more parts.

I just purchased a 2020 Stampede 4 XT EPS about 30 days ago.  Like you I really couldn't find any reviews or information outside of the Arctic Cat website.  I think this is because Textron who bought Arctic Cat back in 2017 recently decided to bring the Arctic Cat name back to their UTV's after originally only using it on the snowmobiles post acquisition.  From the best I could tell this is the same 4 stroke engine that Textron had in the Recoil and Ambush models.   It's now being built in one of their MN facilities after moving production from Germany so it appears the whole machine is now built in MN.  I ended up purchasing the Stampede because I am familiar with the reliability of the Arctic Cat snowmobile brand from growing up in the north, the great standard features it comes with and the significant rebates that Artic Cat is currently giving.  I will say that down in Texas where I live they are extremely difficult to get.  I ended up having to go up to OK to pick one up.  I was told this was because this is a new model and the plant has been shut down due to the Pandemic.   So far I really like the Stampede.  I only have about 20 hours on it but so far it's been a great vehicle.  Have mostly used it around our property to haul fencing equipment and other misc items.  I have taken it out in the mud a few times, once with a buddy who has a smaller Razor.  Obviously the Razor is more designed for off road so it was more nimble but overall it didn't blow my doors off by any stretch of the imagination and I was able to hang on it's tail almost all the time.   For me the real test will be in the long term durability of it because so far the initial performance and quality have been really good.  So far it's been well worth the long drive to pick it up and the money.