Hey thanks again everyone for helping me with my original question.. Bear with me, but I am still confused as to how all of us that bought 2017 or newer units can get back to the prior models performance where the top speed was much faster. (up to 50 mph per magazines reviews) .
If any Advanced Members can make it really clear what Hisun exactly did to slow the machine down, then the the rest of us with 2017 machines have a chance at getting the top speed back.
I have been told that the EFI module (Delphi MT05) has been reprogrammed and a spark cutoff has been added at 7000 rpm. I can confirm the cutoff with my machine! It makes it extremely annoying for anyone to ride behind this machine on the trails and roads while the engine continuously hits up against the cutoff. It does not just happen once and a while, but all the time while riding! It's terrible! Sounds like the machine is constantly backfiring! If this is really true, then we should be able to replace the current 2017 ECU with an older pre 2017 version with the old software, right? If anyone can answer this question, that would be really good to know. Not a cheap solution, but at least gets us back to where we expected the machine to perform and eliminates the extremely annoying lower spark cutout at 7000 rpm... Also, for anyone that has a pre 2017 machine, can you confirm what is the max RPM you get off the dash when you have the machine at full throttle? Is it 7500, 8000, 8500 or what? This will help us understand what else was changed on the machine to effect the top speed.
I have also been told by people in the blog that the final ratio on the machine has been changed as well on the 2017. I currently have 11 tooth drive gear and 42 teeth on the final sprocket. It has been suggested to change the final sprocket to 38 to get some speed back. Unfortunately when I do the math, you only gain 3.1 mph. This helps a bit, but I am still way off in my mission to go from 30 mph to 50 mph... So I am still confused. See the math and the speed table I have attached. I am not very smart, so if anyone can show me the error in my calcs, feel free to correct. Note: Since I was not able to count the gear teeth in the gear transmission, I solved backwards for the gear transmission ratio in high gear to be 4:1. At engine an speed of 7000 rpm, 4:1 ratio in the transmission, 11/42 ratio on the final sprockets, and a 22 in dia. tire, it gives me my current measured speed off the machine (gps) of 30mph. Just to be sure, if anyone can confirm the transmission ratio to be 4:1 in high, that would help as well as what is the tooth count for the Drive and Driven sprockets on machines pre 2017. This would also be huge because then in addition to changing out the ECU, we could simply just buy the older sprockets (and chain) with the original ratio and get our speed back!
Now, I still have one more area that we did not address.. The CVT. Did they change it to effect the top speed? On my little 90 cc Kawasaki ATV, they put a spacer in the primary clutch to prevent it from closing all the way and get the final ratio. I heard this was common on the smaller kids machines to slow them down when the kids were small, and could be removed by parents as the kids got older. Can anyone comment as to whether Hisun would have modified the primary clutch on the 2017 models, limiting the travel of the two sheaves? I still think about this one because when I ride the machine, it seem to climb to 7000 rpm very quickly and then cutout. It definitely feels there should be more top speed prior to hitting the cutoff. It feels as thought the clutches cannot get to their final ratio. (belt highest on Drive clutch, lowest on Driven clutch) Any insights?
The last question I have is related to the response I got from Strike 250 Advanced Member:
Hello there, there are a couple of things to address here. First off is to make sure when the throttle peddle pressed all the way down, that the throttle is also opening all the way. You can check this by removing the center cover. When you press down on the throttle, reach over to the butterfly valve and see if you can open the throttle any more on the throttle body. If so, adjust the throttle cable. But you need to make sure when the throttle is released that the throttle also closes as well. Meaning you will have just a little bit of slack in the throttle cable. You don't want the throttle body hanging up causing the engine to rev. After that, there is come control in the ECU, but there is also a electronic speed limiter, located under the dash by the winch control box. Try to make sure the throttle is adjusted properly first and let me know. Matt
I have not got a chance to adjust the throttle cable yet, but I will follow your advice. Since I was accelerating good up to 7000 rpm and the cutout was kicking in, it did not seem like my issue was a partial throttle condition, but I will chack any how. The big questions I have is the "electronic speed limiter under the dash" that you mentioned... What exactly is this and what does it look like? Is this the real problem? Nobody else could confirm this existed.. Could not find it the first time I looked. Any more information you can give on this would be AWESOME!!
BTW, my dealer has been totally useless since I gave him the check, so it anyone can recommend a good place to get parts for the unit, let me know. Thanks!
Please, if anyone can help out and make this speed thing simple, it would be great for the rest of us! Even better would be if someone was to offer a kit will all the components to get the machine to perform at pre 2017, I bet everyone would buy it!!
Love the machine, hate the performance!
Strike 250 Speed Calculations.xlsx